Removed Trace

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/MilliSpan.java

@@ -45,12 +45,32 @@ public class MilliSpan implements Span {
 	private final String processId;
 	@Singular
 	private final List<Log> logs = new ArrayList<>();
+	private final Span savedSpan;
 
 	public static MilliSpan.MilliSpanBuilder builder() {
 		return new MilliSpan().toBuilder();
 	}
 
+	public MilliSpan(Span current, Span savedSpan) {
+		this.begin = current.getBegin();
+		this.end = current.getEnd();
+		this.name = current.getName();
+		this.traceId = current.getTraceId();
+		this.parents = current.getParents();
+		this.spanId = current.getSpanId();
+		this.remote = current.isRemote();
+		this.exportable = current.isExportable();
+		this.processId = current.getProcessId();
+		this.tags.putAll(current.tags());
+		this.logs.addAll(current.logs());
+		this.savedSpan = savedSpan;
+	}
+
 	public MilliSpan(long begin, long end, String name, long traceId, List<Long> parents, long spanId, boolean remote, boolean exportable, String processId) {
+		this(begin, end, name, traceId, parents, spanId, remote, exportable, processId, null);
+	}
+
+	public MilliSpan(long begin, long end, String name, long traceId, List<Long> parents, long spanId, boolean remote, boolean exportable, String processId, Span savedSpan) {
 		this.begin = begin<=0 ? System.currentTimeMillis() : begin;
 		this.end = end;
 		this.name = name;
@@ -60,6 +80,7 @@ public class MilliSpan implements Span {
 		this.remote = remote;
 		this.exportable = exportable;
 		this.processId = processId;
+		this.savedSpan = savedSpan;
 	}
 
 	//for serialization
@@ -70,6 +91,7 @@ public class MilliSpan implements Span {
 		this.spanId = 0;
 		this.processId = null;
 		this.parents = new ArrayList<>();
+		this.savedSpan = null;
 	}
 
 	@Override
@@ -120,4 +142,9 @@ public class MilliSpan implements Span {
 		return Collections.unmodifiableList(this.logs);
 	}
 
+	@Override
+	public boolean hasSavedSpan() {
+		return savedSpan != null;
+	}
+
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/Span.java

@@ -19,6 +19,7 @@ package org.springframework.cloud.sleuth;
 import org.springframework.util.Assert;
 
 import java.math.BigInteger;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
@@ -31,6 +32,16 @@ import java.util.Map;
  */
 public interface Span {
 
+	String NOT_SAMPLED_NAME = "X-Not-Sampled";
+	String PROCESS_ID_NAME = "X-Process-Id";
+	String PARENT_ID_NAME = "X-Parent-Id";
+	String TRACE_ID_NAME = "X-Trace-Id";
+	String SPAN_NAME_NAME = "X-Span-Name";
+	String SPAN_ID_NAME = "X-Span-Id";
+	List<String> HEADERS = Arrays.asList(SPAN_ID_NAME, TRACE_ID_NAME,
+			SPAN_NAME_NAME, PARENT_ID_NAME, PROCESS_ID_NAME, NOT_SAMPLED_NAME);
+	String SPAN_EXPORT_NAME = "X-Span-Export";
+
 	/**
 	 * A human-readable name assigned to this span instance.
 	 * <p/>
@@ -152,4 +163,15 @@ public interface Span {
 			return new BigInteger(hexString, 16).longValue();
 		}
 	}
+
+	/**
+	 * The span that was "current" before this span was entered
+	 */
+	Span getSavedSpan();
+
+	/**
+	 *
+	 * @return true if there was a "current" span before this span was entered
+	 */
+	boolean hasSavedSpan();
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/Trace.java

@@ -1,71 +0,0 @@
-/*
- * Copyright 2013-2015 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.cloud.sleuth;
-
-import java.util.Arrays;
-import java.util.List;
-
-import lombok.Value;
-import lombok.experimental.NonFinal;
-
-/**
- * A wrapper around the current span with context for a possible hierarchy or stack of
- * spans being monitored.
- *
- * @author Spencer Gibb
- */
-@Value
-@NonFinal
-public class Trace {
-
-	public static final String NOT_SAMPLED_NAME = "X-Not-Sampled";
-
-	public static final String PROCESS_ID_NAME = "X-Process-Id";
-
-	public static final String PARENT_ID_NAME = "X-Parent-Id";
-
-	public static final String TRACE_ID_NAME = "X-Trace-Id";
-
-	public static final String SPAN_NAME_NAME = "X-Span-Name";
-
-	public static final String SPAN_ID_NAME = "X-Span-Id";
-
-	public static final String SPAN_EXPORT_NAME = "X-Span-Export";
-
-	public static final List<String> HEADERS = Arrays.asList(SPAN_ID_NAME, TRACE_ID_NAME,
-			SPAN_NAME_NAME, PARENT_ID_NAME, PROCESS_ID_NAME, NOT_SAMPLED_NAME);
-
-	/**
-	 * the span for this trace
-	 */
-	private final Span span;
-
-	/**
-	 * the trace that was "current" before this trace was entered
-	 */
-	private final Trace saved;
-
-	public Trace(Trace saved, Span span) {
-		this.saved = saved;
-		this.span = span;
-	}
-
-	public Trace(Span span) {
-		this(null, span);
-	}
-
-}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/Tracer.java

@@ -61,7 +61,7 @@ public interface Tracer extends TraceAccessor {
 	 *
 	 * @param name The name field for the new span to create.
 	 */
-	Trace startTrace(String name);
+	Span startTrace(String name);
 
 	/**
 	 * Creates a new trace scope with a specific parent. The parent might be in another
@@ -73,7 +73,7 @@ public interface Tracer extends TraceAccessor {
 	 *
 	 * @param name The name field for the new span to create.
 	 */
-	Trace joinTrace(String name, Span parent);
+	Span joinTrace(String name, Span parent);
 
 	/**
 	 * Start a new span if the sampler allows it or if we are already tracing in this
@@ -81,12 +81,12 @@ public interface Tracer extends TraceAccessor {
 	 *  @param name the name of the span
 	 * @param sampler a sampler to decide whether to create the span or not
 	 */
-	<T> Trace startTrace(String name, Sampler<T> sampler);
+	<T> Span startTrace(String name, Sampler<T> sampler);
 
 	/**
 	 * Pick up an existing span from another thread.
 	 */
-	Trace continueSpan(Span s);
+	Span continueSpan(Span s);
 
 	/**
 	 * Adds a tag to the current span if tracing is currently on.
@@ -100,7 +100,7 @@ public interface Tracer extends TraceAccessor {
 	 *
 	 * @return the saved trace if there was one before the trace started (null otherwise)
 	 */
-	Trace detach(Trace trace);
+	Span detach(Span trace);
 
 	/**
 	 * Remove this span from the current thread, stop it and send it for collection.
@@ -108,7 +108,7 @@ public interface Tracer extends TraceAccessor {
 	 * @param trace the trace to close
 	 * @return the saved trace if there was one before the trace started (null otherwise)
 	 */
-	Trace close(Trace trace);
+	Span close(Span trace);
 
 	<V> Callable<V> wrap(Callable<V> callable);
 

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/bootstrap/TraceBootstrapEnvironmentPostProcessor.java

@@ -21,7 +21,7 @@ import java.util.Map;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.env.EnvironmentPostProcessor;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
@@ -35,9 +35,9 @@ import org.springframework.util.ClassUtils;
 public class TraceBootstrapEnvironmentPostProcessor implements EnvironmentPostProcessor {
 
 	private static final String PROPERTY_SOURCE_NAME = "defaultProperties";
-	private static String[] headers = new String[] { Trace.SPAN_ID_NAME,
-			Trace.TRACE_ID_NAME, Trace.PARENT_ID_NAME, Trace.PROCESS_ID_NAME,
-			Trace.NOT_SAMPLED_NAME, Trace.SPAN_NAME_NAME };
+	private static String[] headers = new String[] { Span.SPAN_ID_NAME,
+			Span.TRACE_ID_NAME, Span.PARENT_ID_NAME, Span.PROCESS_ID_NAME,
+			Span.NOT_SAMPLED_NAME, Span.SPAN_NAME_NAME };
 
 	@Override
 	public void postProcessEnvironment(ConfigurableEnvironment environment,

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/TraceCallable.java

@@ -18,7 +18,7 @@ package org.springframework.cloud.sleuth.instrument;
 
 import java.util.concurrent.Callable;
 
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 
 import lombok.EqualsAndHashCode;
@@ -43,7 +43,7 @@ public class TraceCallable<V> extends TraceDelegate<Callable<V>> implements Call
 	@Override
 	public V call() throws Exception {
 		ensureThatThreadIsNotPollutedByPreviousTraces();
-		Trace trace = startSpan();
+		Span trace = startSpan();
 		try {
 			return this.getDelegate().call();
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/TraceDelegate.java

@@ -16,12 +16,10 @@
 
 package org.springframework.cloud.sleuth.instrument;
 
-import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
-import org.springframework.cloud.sleuth.Tracer;
-
 import lombok.Getter;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.Span;
+import org.springframework.cloud.sleuth.Tracer;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 
 /**
  * @author Spencer Gibb
@@ -45,18 +43,18 @@ public abstract class TraceDelegate<T> {
 		this.parent = tracer.getCurrentSpan();
 	}
 
-	protected void close(Trace trace) {
+	protected void close(Span trace) {
 		this.tracer.close(trace);
 	}
 
-	protected void closeAll(Trace trace) {
+	protected void closeAll(Span trace) {
 		trace = this.tracer.close(trace);
 		while (trace != null) {
 			trace = this.tracer.detach(trace);
 		}
 	}
 
-	protected Trace startSpan() {
+	protected Span startSpan() {
 		return this.tracer.joinTrace(getSpanName(), this.parent);
 	}
 
@@ -65,6 +63,6 @@ public abstract class TraceDelegate<T> {
 	}
 
 	protected void ensureThatThreadIsNotPollutedByPreviousTraces() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/TraceRunnable.java

@@ -16,7 +16,7 @@
 
 package org.springframework.cloud.sleuth.instrument;
 
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 
 import lombok.EqualsAndHashCode;
@@ -40,7 +40,7 @@ public class TraceRunnable extends TraceDelegate<Runnable> implements Runnable {
 	@Override
 	public void run() {
 		ensureThatThreadIsNotPollutedByPreviousTraces();
-		Trace trace = startSpan();
+		Span trace = startSpan();
 		try {
 			this.getDelegate().run();
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/hystrix/TraceCommand.java

@@ -20,9 +20,8 @@ import com.netflix.hystrix.HystrixCommand;
 import com.netflix.hystrix.HystrixCommandGroupKey;
 import com.netflix.hystrix.HystrixThreadPoolKey;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 
 /**
  * Abstraction over {@code HystrixCommand} that wraps command execution with Trace setting
@@ -72,7 +71,7 @@ public abstract class TraceCommand<R> extends HystrixCommand<R> {
 	@Override
 	protected R run() throws Exception {
 		enforceThatHystrixThreadIsNotPollutedByPreviousTraces();
-		Trace trace = this.tracer.joinTrace(getCommandKey().name(), parentSpan);
+		Span trace = this.tracer.joinTrace(getCommandKey().name(), parentSpan);
 		try {
 			return doRun();
 		} finally {
@@ -82,7 +81,7 @@ public abstract class TraceCommand<R> extends HystrixCommand<R> {
 
 	// TODO: Do more analysis why this is not removed properly
 	private void enforceThatHystrixThreadIsNotPollutedByPreviousTraces() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	public abstract R doRun() throws Exception;

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/integration/TraceContextPropagationChannelInterceptor.java

@@ -18,7 +18,6 @@ package org.springframework.cloud.sleuth.instrument.integration;
 
 import org.springframework.aop.support.AopUtils;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.messaging.Message;
@@ -50,7 +49,7 @@ public class TraceContextPropagationChannelInterceptor extends ChannelIntercepto
 
 	private final Tracer tracer;
 
-	private final static ThreadLocal<Trace> ORIGINAL_CONTEXT = new ThreadLocal<>();
+	private final static ThreadLocal<Span> ORIGINAL_CONTEXT = new ThreadLocal<>();
 
 	public TraceContextPropagationChannelInterceptor(Tracer tracer) {
 		this.tracer = tracer;
@@ -101,12 +100,12 @@ public class TraceContextPropagationChannelInterceptor extends ChannelIntercepto
 	protected void populatePropagatedContext(Span span, Message<?> message,
 			MessageChannel channel) {
 		if (span != null) {
-			ORIGINAL_CONTEXT.set(this.tracer.continueSpan(span).getSaved());
+			ORIGINAL_CONTEXT.set(this.tracer.continueSpan(span).getSavedSpan());
 		}
 	}
 
 	protected void resetPropagatedContext() {
-		Trace originalContext = ORIGINAL_CONTEXT.get();
+		Span originalContext = ORIGINAL_CONTEXT.get();
 		this.tracer.detach(originalContext);
 		ORIGINAL_CONTEXT.remove();
 	}
@@ -128,16 +127,16 @@ public class TraceContextPropagationChannelInterceptor extends ChannelIntercepto
 			Map<String, Object> headers = new HashMap<>();
 			headers.putAll(message.getHeaders());
 
-			setHeader(headers, Trace.SPAN_ID_NAME, this.span.getSpanId());
-			setHeader(headers, Trace.TRACE_ID_NAME, this.span.getTraceId());
-			setHeader(headers, Trace.SPAN_NAME_NAME, this.span.getName());
+			setHeader(headers, Span.SPAN_ID_NAME, this.span.getSpanId());
+			setHeader(headers, Span.TRACE_ID_NAME, this.span.getTraceId());
+			setHeader(headers, Span.SPAN_NAME_NAME, this.span.getName());
 			Long parentId = getParentId(span);
 			if (parentId != null) {
-				setHeader(headers, Trace.PARENT_ID_NAME, parentId);
+				setHeader(headers, Span.PARENT_ID_NAME, parentId);
 			}
 			String processId = span.getProcessId();
 			if (StringUtils.hasText(processId)) {
-				setHeader(headers, Trace.PROCESS_ID_NAME, processId);
+				setHeader(headers, Span.PROCESS_ID_NAME, processId);
 			}
 			this.messageHeaders = new MessageHeaders(headers);
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/scheduling/TraceSchedulingAspect.java

@@ -19,7 +19,7 @@ package org.springframework.cloud.sleuth.instrument.scheduling;
 import org.aspectj.lang.ProceedingJoinPoint;
 import org.aspectj.lang.annotation.Around;
 import org.aspectj.lang.annotation.Aspect;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.scheduling.annotation.Scheduled;
 
@@ -46,7 +46,7 @@ public class TraceSchedulingAspect {
 
 	@Around("execution (@org.springframework.scheduling.annotation.Scheduled  * *.*(..))")
 	public Object traceBackgroundThread(final ProceedingJoinPoint pjp) throws Throwable {
-		Trace trace = this.tracer.startTrace(pjp.toShortString());
+		Span trace = this.tracer.startTrace(pjp.toShortString());
 		try {
 			return pjp.proceed();
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/TraceFilter.java

@@ -32,13 +32,12 @@ import javax.servlet.http.HttpServletResponse;
 import org.springframework.cloud.sleuth.MilliSpan;
 import org.springframework.cloud.sleuth.MilliSpan.MilliSpanBuilder;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.event.ServerReceivedEvent;
 import org.springframework.cloud.sleuth.event.ServerSentEvent;
 import org.springframework.cloud.sleuth.instrument.TraceKeys;
 import org.springframework.cloud.sleuth.sampler.IsTracingSampler;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
@@ -49,15 +48,15 @@ import org.springframework.web.filter.OncePerRequestFilter;
 import org.springframework.web.util.UrlPathHelper;
 
 /**
- * Filter that takes the value of the {@link Trace#SPAN_ID_NAME} and
- * {@link Trace#TRACE_ID_NAME} header from either request or response and uses them to
+ * Filter that takes the value of the {@link Span#SPAN_ID_NAME} and
+ * {@link Span#TRACE_ID_NAME} header from either request or response and uses them to
  * create a new span.
  *
  * <p>In order to keep the size of spans manageable, this only add tags defined in {@link TraceKeys}.
  * If you need to add additional tags, such as headers subtype this and override
  * {@link #addRequestTags} or {@link #addResponseTags}.
  *
- * @see TraceManager
+ * @see Tracer
  * @see TraceKeys
  * @see TraceWebAutoConfiguration#traceWebFilter(TraceFilter)
  *
@@ -106,32 +105,32 @@ public class TraceFilter extends OncePerRequestFilter
 	protected void doFilterInternal(HttpServletRequest request,
 			HttpServletResponse response, FilterChain filterChain)
 					throws ServletException, IOException {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 
 		String uri = this.urlPathHelper.getPathWithinApplication(request);
 		boolean skip = this.skipPattern.matcher(uri).matches()
-				|| getHeader(request, response, Trace.NOT_SAMPLED_NAME) != null;
+				|| getHeader(request, response, Span.NOT_SAMPLED_NAME) != null;
 
-		Trace trace = (Trace) request.getAttribute(TRACE_REQUEST_ATTR);
+		Span trace = (Span) request.getAttribute(TRACE_REQUEST_ATTR);
 		if (trace != null) {
-			this.tracer.continueSpan(trace.getSpan());
+			this.tracer.continueSpan(trace);
 		}
 		else if (skip) {
-			addToResponseIfNotPresent(response, Trace.NOT_SAMPLED_NAME, "");
+			addToResponseIfNotPresent(response, Span.NOT_SAMPLED_NAME, "");
 		}
 
 		String name = "http" + uri;
-		if (hasHeader(request, response, Trace.TRACE_ID_NAME)) {
-			long traceId = Span.IdConverter.fromHex(getHeader(request, response, Trace.TRACE_ID_NAME));
-			long spanId = hasHeader(request, response, Trace.SPAN_ID_NAME) ?
-					Span.IdConverter.fromHex(getHeader(request, response, Trace.SPAN_ID_NAME)) : this.random.nextLong();
+		if (hasHeader(request, response, Span.TRACE_ID_NAME)) {
+			long traceId = Span.IdConverter.fromHex(getHeader(request, response, Span.TRACE_ID_NAME));
+			long spanId = hasHeader(request, response, Span.SPAN_ID_NAME) ?
+					Span.IdConverter.fromHex(getHeader(request, response, Span.SPAN_ID_NAME)) : this.random.nextLong();
 
 			MilliSpanBuilder span = MilliSpan.builder().traceId(traceId).spanId(spanId);
 			if (skip) {
 				span.exportable(false);
 			}
-			String processId = getHeader(request, response, Trace.PROCESS_ID_NAME);
-			String parentName = getHeader(request, response, Trace.SPAN_NAME_NAME);
+			String processId = getHeader(request, response, Span.PROCESS_ID_NAME);
+			String parentName = getHeader(request, response, Span.SPAN_NAME_NAME);
 			if (StringUtils.hasText(parentName)) {
 				span.name(parentName);
 			} else {
@@ -140,14 +139,14 @@ public class TraceFilter extends OncePerRequestFilter
 			if (StringUtils.hasText(processId)) {
 				span.processId(processId);
 			}
-			if (hasHeader(request, response, Trace.PARENT_ID_NAME)) {
-				span.parent(Span.IdConverter.fromHex(getHeader(request, response, Trace.PARENT_ID_NAME)));
+			if (hasHeader(request, response, Span.PARENT_ID_NAME)) {
+				span.parent(Span.IdConverter.fromHex(getHeader(request, response, Span.PARENT_ID_NAME)));
 			}
 			span.remote(true);
 
 			Span parent = span.build();
 			trace = this.tracer.joinTrace(name, parent);
-			publish(new ServerReceivedEvent(this, parent, trace.getSpan()));
+			publish(new ServerReceivedEvent(this, parent, trace));
 			request.setAttribute(TRACE_REQUEST_ATTR, trace);
 
 		}
@@ -179,14 +178,14 @@ public class TraceFilter extends OncePerRequestFilter
 				return;
 			}
 			if (skip) {
-				addToResponseIfNotPresent(response, Trace.NOT_SAMPLED_NAME, "");
+				addToResponseIfNotPresent(response, Span.NOT_SAMPLED_NAME, "");
 			}
 			if (trace != null) {
 				addResponseTags(response, exception);
-				addResponseHeaders(response, trace.getSpan());
-				if (trace.getSaved() != null) {
-					publish(new ServerSentEvent(this, trace.getSaved().getSpan(),
-							trace.getSpan()));
+				addResponseHeaders(response, trace);
+				if (trace.hasSavedSpan()) {
+					publish(new ServerSentEvent(this, trace.getSavedSpan(),
+							trace));
 				}
 				// Double close to clean up the parent (remote span as well)
 				this.tracer.close(this.tracer.close(trace));
@@ -196,8 +195,8 @@ public class TraceFilter extends OncePerRequestFilter
 
 	private void addResponseHeaders(HttpServletResponse response, Span span) {
 		if (span != null) {
-			response.addHeader(Trace.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
-			response.addHeader(Trace.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
+			response.addHeader(Span.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
+			response.addHeader(Span.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
 		}
 	}
 

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/TraceHandlerInterceptor.java

@@ -16,14 +16,14 @@
 
 package org.springframework.cloud.sleuth.instrument.web;
 
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.ModelAndView;
 
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
 /**
  * @author Spencer Gibb
  */
@@ -42,8 +42,8 @@ public class TraceHandlerInterceptor implements HandlerInterceptor {
 			Object handler) throws Exception {
 		// TODO: get trace data from request?
 		// TODO: what is the description?
-		Trace trace = this.tracer.startTrace("traceHandlerInterceptor");
-		request.setAttribute(ATTR_NAME, trace);
+		Span span = this.tracer.startTrace("traceHandlerInterceptor");
+		request.setAttribute(ATTR_NAME, span);
 		return true;
 	}
 
@@ -56,7 +56,7 @@ public class TraceHandlerInterceptor implements HandlerInterceptor {
 	@Override
 	public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
 			Object handler, Exception ex) throws Exception {
-		Trace trace = Trace.class.cast(request.getAttribute(ATTR_NAME));
-		this.tracer.close(trace);
+		Span span = Span.class.cast(request.getAttribute(ATTR_NAME));
+		this.tracer.close(span);
 	}
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceFeignClientAutoConfiguration.java

@@ -36,7 +36,6 @@ import org.springframework.cloud.netflix.feign.FeignAutoConfiguration;
 import org.springframework.cloud.netflix.feign.support.ResponseEntityDecoder;
 import org.springframework.cloud.netflix.feign.support.SpringDecoder;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.event.ClientReceivedEvent;
@@ -123,14 +122,14 @@ public class TraceFeignClientAutoConfiguration {
 			public void apply(RequestTemplate template) {
 				Span span = getCurrentSpan();
 				if (span == null) {
-					setHeader(template, Trace.NOT_SAMPLED_NAME, "");
+					setHeader(template, Span.NOT_SAMPLED_NAME, "");
 					return;
 				}
-				template.header(Trace.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
-				setHeader(template, Trace.SPAN_NAME_NAME, span.getName());
-				setHeader(template, Trace.SPAN_ID_NAME, span.getSpanId());
-				setHeader(template, Trace.PARENT_ID_NAME, getParentId(span));
-				setHeader(template, Trace.PROCESS_ID_NAME, span.getProcessId());
+				template.header(Span.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
+				setHeader(template, Span.SPAN_NAME_NAME, span.getName());
+				setHeader(template, Span.SPAN_ID_NAME, span.getSpanId());
+				setHeader(template, Span.PARENT_ID_NAME, getParentId(span));
+				setHeader(template, Span.PROCESS_ID_NAME, span.getProcessId());
 				publish(new ClientSentEvent(this, span));
 			}
 		};
@@ -166,12 +165,12 @@ public class TraceFeignClientAutoConfiguration {
 		newHeaders.putAll(headers);
 		Span span = getCurrentSpan();
 		if (span == null) {
-			setHeader(newHeaders, Trace.NOT_SAMPLED_NAME, "");
+			setHeader(newHeaders, Span.NOT_SAMPLED_NAME, "");
 			return newHeaders;
 		}
-		setHeader(newHeaders, Trace.TRACE_ID_NAME, span.getTraceId());
-		setHeader(newHeaders, Trace.SPAN_ID_NAME, span.getSpanId());
-		setHeader(newHeaders, Trace.PARENT_ID_NAME, getParentId(span));
+		setHeader(newHeaders, Span.TRACE_ID_NAME, span.getTraceId());
+		setHeader(newHeaders, Span.SPAN_ID_NAME, span.getSpanId());
+		setHeader(newHeaders, Span.PARENT_ID_NAME, getParentId(span));
 		return newHeaders;
 	}
 

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceRestTemplateInterceptor.java

@@ -16,7 +16,6 @@
 package org.springframework.cloud.sleuth.instrument.web.client;
 
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.event.ClientReceivedEvent;
 import org.springframework.cloud.sleuth.event.ClientSentEvent;
@@ -62,14 +61,14 @@ ApplicationEventPublisherAware {
 			ClientHttpRequestExecution execution) throws IOException {
 		Span span = getCurrentSpan();
 		if (span == null) {
-			setHeader(request, Trace.NOT_SAMPLED_NAME, "");
+			setHeader(request, Span.NOT_SAMPLED_NAME, "");
 			return execution.execute(request, body);
 		}
-		setHeader(request, Trace.TRACE_ID_NAME, span.getTraceId());
-		setHeader(request, Trace.SPAN_ID_NAME, span.getSpanId());
-		setHeader(request, Trace.SPAN_NAME_NAME, span.getName());
-		setHeader(request, Trace.PARENT_ID_NAME, getParentId(span));
-		setHeader(request, Trace.PROCESS_ID_NAME, span.getProcessId());
+		setHeader(request, Span.TRACE_ID_NAME, span.getTraceId());
+		setHeader(request, Span.SPAN_ID_NAME, span.getSpanId());
+		setHeader(request, Span.SPAN_NAME_NAME, span.getName());
+		setHeader(request, Span.PARENT_ID_NAME, getParentId(span));
+		setHeader(request, Span.PROCESS_ID_NAME, span.getProcessId());
 		publish(new ClientSentEvent(this, span));
 		return new TraceHttpResponse(this, execution.execute(request, body));
 	}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/zuul/TracePreZuulFilter.java

@@ -19,7 +19,6 @@ package org.springframework.cloud.sleuth.instrument.zuul;
 import com.netflix.zuul.ZuulFilter;
 import com.netflix.zuul.context.RequestContext;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.event.ClientSentEvent;
 import org.springframework.context.ApplicationEvent;
@@ -61,15 +60,15 @@ ApplicationEventPublisherAware {
 		// N.B. this will only work with the simple host filter (not ribbon) unless you set hystrix.execution.isolation.strategy=SEMAPHORE
 		Span span = getCurrentSpan();
 		if (span == null) {
-			setHeader(response, Trace.NOT_SAMPLED_NAME, "");
+			setHeader(response, Span.NOT_SAMPLED_NAME, "");
 			return null;
 		}
 		try {
-			setHeader(response, Trace.SPAN_ID_NAME, span.getSpanId());
-			setHeader(response, Trace.TRACE_ID_NAME, span.getTraceId());
-			setHeader(response, Trace.SPAN_NAME_NAME, span.getName());
-			setHeader(response, Trace.PARENT_ID_NAME, getParentId(span));
-			setHeader(response, Trace.PROCESS_ID_NAME, span.getProcessId());
+			setHeader(response, Span.SPAN_ID_NAME, span.getSpanId());
+			setHeader(response, Span.TRACE_ID_NAME, span.getTraceId());
+			setHeader(response, Span.SPAN_NAME_NAME, span.getName());
+			setHeader(response, Span.PARENT_ID_NAME, getParentId(span));
+			setHeader(response, Span.PROCESS_ID_NAME, span.getProcessId());
 			// TODO: the client sent event should come from the client not the filter!
 			publish(new ClientSentEvent(this, span));
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/zuul/TraceRestClientRibbonCommandFactory.java

@@ -24,7 +24,6 @@ import org.springframework.cloud.netflix.zuul.filters.route.RestClientRibbonComm
 import org.springframework.cloud.netflix.zuul.filters.route.RestClientRibbonCommandFactory;
 import org.springframework.cloud.netflix.zuul.filters.route.RibbonCommandContext;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.event.ClientSentEvent;
 import org.springframework.context.ApplicationEvent;
@@ -91,15 +90,15 @@ public class TraceRestClientRibbonCommandFactory extends RestClientRibbonCommand
 		protected void customizeRequest(HttpRequest.Builder requestBuilder) {
 			Span span = getCurrentSpan();
 			if (span == null) {
-				setHeader(requestBuilder, Trace.NOT_SAMPLED_NAME, "");
+				setHeader(requestBuilder, Span.NOT_SAMPLED_NAME, "");
 				return;
 			}
-			setHeader(requestBuilder, Trace.TRACE_ID_NAME, span.getTraceId());
-			setHeader(requestBuilder, Trace.SPAN_ID_NAME, span.getSpanId());
-			setHeader(requestBuilder, Trace.SPAN_NAME_NAME, span.getName());
-			setHeader(requestBuilder, Trace.PARENT_ID_NAME,
+			setHeader(requestBuilder, Span.TRACE_ID_NAME, span.getTraceId());
+			setHeader(requestBuilder, Span.SPAN_ID_NAME, span.getSpanId());
+			setHeader(requestBuilder, Span.SPAN_NAME_NAME, span.getName());
+			setHeader(requestBuilder, Span.PARENT_ID_NAME,
 					getParentId(span));
-			setHeader(requestBuilder, Trace.PROCESS_ID_NAME,
+			setHeader(requestBuilder, Span.PROCESS_ID_NAME,
 					span.getProcessId());
 			publish(new ClientSentEvent(this, span));
 		}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/log/Slf4jSpanListener.java

@@ -18,7 +18,6 @@ package org.springframework.cloud.sleuth.log;
 
 import org.slf4j.MDC;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.event.SpanAcquiredEvent;
 import org.springframework.cloud.sleuth.event.SpanContinuedEvent;
 import org.springframework.cloud.sleuth.event.SpanReleasedEvent;
@@ -38,9 +37,9 @@ public class Slf4jSpanListener {
 	@Order(Ordered.LOWEST_PRECEDENCE)
 	public void start(SpanAcquiredEvent event) {
 		Span span = event.getSpan();
-		MDC.put(Trace.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
-		MDC.put(Trace.SPAN_EXPORT_NAME, String.valueOf(span.isExportable()));
-		MDC.put(Trace.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
+		MDC.put(Span.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
+		MDC.put(Span.SPAN_EXPORT_NAME, String.valueOf(span.isExportable()));
+		MDC.put(Span.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
 		log.trace("Starting span: {}", span);
 		if (event.getParent() != null) {
 			log.trace("With parent: {}", event.getParent());
@@ -51,9 +50,9 @@ public class Slf4jSpanListener {
 	@Order(Ordered.LOWEST_PRECEDENCE)
 	public void continued(SpanContinuedEvent event) {
 		Span span = event.getSpan();
-		MDC.put(Trace.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
-		MDC.put(Trace.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
-		MDC.put(Trace.SPAN_EXPORT_NAME, String.valueOf(span.isExportable()));
+		MDC.put(Span.SPAN_ID_NAME, Span.IdConverter.toHex(span.getSpanId()));
+		MDC.put(Span.TRACE_ID_NAME, Span.IdConverter.toHex(span.getTraceId()));
+		MDC.put(Span.SPAN_EXPORT_NAME, String.valueOf(span.isExportable()));
 		log.trace("Continued span: {}", event.getSpan());
 	}
 
@@ -63,13 +62,13 @@ public class Slf4jSpanListener {
 		log.trace("Stopped span: {}", event.getSpan());
 		if (event.getParent() != null) {
 			log.trace("With parent: {}", event.getParent());
-			MDC.put(Trace.SPAN_ID_NAME, Span.IdConverter.toHex(event.getParent().getSpanId()));
-			MDC.put(Trace.SPAN_EXPORT_NAME, String.valueOf(event.getParent().isExportable()));
+			MDC.put(Span.SPAN_ID_NAME, Span.IdConverter.toHex(event.getParent().getSpanId()));
+			MDC.put(Span.SPAN_EXPORT_NAME, String.valueOf(event.getParent().isExportable()));
 		}
 		else {
-			MDC.remove(Trace.SPAN_ID_NAME);
-			MDC.remove(Trace.SPAN_EXPORT_NAME);
-			MDC.remove(Trace.TRACE_ID_NAME);
+			MDC.remove(Span.SPAN_ID_NAME);
+			MDC.remove(Span.SPAN_EXPORT_NAME);
+			MDC.remove(Span.TRACE_ID_NAME);
 		}
 	}
 

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/sampler/IsTracingSampler.java

@@ -17,7 +17,7 @@
 package org.springframework.cloud.sleuth.sampler;
 
 import org.springframework.cloud.sleuth.Sampler;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 
 /**
  * @author Spencer Gibb
@@ -28,6 +28,6 @@ public class IsTracingSampler implements Sampler<Void> {
 
 	@Override
 	public boolean next() {
-		return TraceContextHolder.isTracing();
+		return SpanContextHolder.isTracing();
 	}
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/template/TraceCallback.java

@@ -16,8 +16,8 @@
 
 package org.springframework.cloud.sleuth.template;
 
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 
 public interface TraceCallback<T> {
-	T doInTrace(Trace trace);
+	T doInTrace(Span trace);
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/trace/DefaultTracer.java

@@ -24,7 +24,6 @@ import java.util.concurrent.Callable;
 import org.springframework.cloud.sleuth.MilliSpan;
 import org.springframework.cloud.sleuth.Sampler;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.event.SpanAcquiredEvent;
 import org.springframework.cloud.sleuth.event.SpanContinuedEvent;
@@ -53,7 +52,7 @@ public class DefaultTracer implements Tracer {
 	}
 
 	@Override
-	public Trace joinTrace(String name, Span parent) {
+	public Span joinTrace(String name, Span parent) {
 		if (parent == null) {
 			return startTrace(name);
 		}
@@ -67,12 +66,12 @@ public class DefaultTracer implements Tracer {
 	}
 
 	@Override
-	public Trace startTrace(String name) {
+	public Span startTrace(String name) {
 		return this.startTrace(name, this.defaultSampler);
 	}
 
 	@Override
-	public <T> Trace startTrace(String name, Sampler<T> s) {
+	public <T> Span startTrace(String name, Sampler<T> s) {
 		Span span = null;
 		if (isTracing() || s.next()) {
 			span = createChild(getCurrentSpan(), name);
@@ -88,12 +87,11 @@ public class DefaultTracer implements Tracer {
 	}
 
 	@Override
-	public Trace detach(Trace trace) {
-		if (trace == null) {
+	public Span detach(Span span) {
+		if (span == null) {
 			return null;
 		}
-		Span cur = TraceContextHolder.getCurrentSpan();
-		Span span = trace.getSpan();
+		Span cur = SpanContextHolder.getCurrentSpan();
 		if (cur != span) {
 			ExceptionUtils.warn("Tried to detach trace span but "
 					+ "it is not the current span for the '"
@@ -101,24 +99,23 @@ public class DefaultTracer implements Tracer {
 					+ ". You have " + "probably forgotten to close or detach " + cur);
 		}
 		else {
-			if (trace.getSaved() != null) {
-				TraceContextHolder.setCurrentTrace(trace.getSaved());
+			if (span.hasSavedSpan()) {
+				SpanContextHolder.setCurrentSpan(span.getSavedSpan());
 			}
 			else {
-				TraceContextHolder.removeCurrentTrace();
+				SpanContextHolder.removeCurrentSpan();
 			}
 		}
-		return trace.getSaved();
+		return span.getSavedSpan();
 	}
 
 	@Override
-	public Trace close(Trace trace) {
-		if (trace == null) {
+	public Span close(Span span) {
+		if (span == null) {
 			return null;
 		}
-		Span cur = TraceContextHolder.getCurrentSpan();
-		Span span = trace.getSpan();
-		Trace savedTrace = trace.getSaved();
+		Span cur = SpanContextHolder.getCurrentSpan();
+		Span savedSpan = span.getSavedSpan();
 		if (cur != span) {
 			ExceptionUtils.warn("Tried to close trace span but "
 					+ "it is not the current span for the '"
@@ -128,24 +125,24 @@ public class DefaultTracer implements Tracer {
 		else {
 			if (span != null) {
 				span.stop();
-				if (savedTrace != null
-						&& span.getParents().contains(savedTrace.getSpan().getSpanId())) {
+				if (savedSpan != null
+						&& span.getParents().contains(savedSpan.getSpanId())) {
 					this.publisher.publishEvent(
-							new SpanReleasedEvent(this, savedTrace.getSpan(), span));
-					TraceContextHolder.setCurrentTrace(savedTrace);
+							new SpanReleasedEvent(this, savedSpan, span));
+					SpanContextHolder.setCurrentSpan(savedSpan);
 				}
 				else {
 					if (!span.isRemote()) {
 						this.publisher.publishEvent(new SpanReleasedEvent(this, span));
 					}
-					TraceContextHolder.removeCurrentTrace();
+					SpanContextHolder.removeCurrentSpan();
 				}
 			}
 			else {
-				TraceContextHolder.removeCurrentTrace();
+				SpanContextHolder.removeCurrentSpan();
 			}
 		}
-		return savedTrace;
+		return savedSpan;
 	}
 
 	protected Span createChild(Span parent, String name) {
@@ -157,9 +154,9 @@ public class DefaultTracer implements Tracer {
 			return span;
 		}
 		else {
-			if (TraceContextHolder.getCurrentTrace() == null) {
-				Trace trace = createTrace(null, parent);
-				TraceContextHolder.setCurrentTrace(trace);
+			if (SpanContextHolder.getCurrentSpan() == null) {
+				Span span = createSpan(null, parent);
+				SpanContextHolder.setCurrentSpan(span);
 			}
 			MilliSpan span = MilliSpan.builder().begin(System.currentTimeMillis())
 					.name(name).traceId(parent.getTraceId()).parent(parent.getSpanId())
@@ -174,27 +171,27 @@ public class DefaultTracer implements Tracer {
 	}
 
 	@Override
-	public Trace continueSpan(Span span) {
+	public Span continueSpan(Span span) {
 		if (span != null) {
 			this.publisher.publishEvent(new SpanContinuedEvent(this, span));
 		}
-		Trace trace = createTrace(TraceContextHolder.getCurrentTrace(), span);
-		TraceContextHolder.setCurrentTrace(trace);
-		return trace;
+		Span newSpan = createSpan(SpanContextHolder.getCurrentSpan(), span);
+		SpanContextHolder.setCurrentSpan(newSpan);
+		return newSpan;
 	}
 
-	protected Trace createTrace(Trace trace, Span span) {
-		return new Trace(trace, span);
+	protected Span createSpan(Span saved, Span span) {
+		return new MilliSpan(span, saved);
 	}
 
 	@Override
 	public Span getCurrentSpan() {
-		return TraceContextHolder.getCurrentSpan();
+		return SpanContextHolder.getCurrentSpan();
 	}
 
 	@Override
 	public boolean isTracing() {
-		return TraceContextHolder.isTracing();
+		return SpanContextHolder.isTracing();
 	}
 
 	@Override

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/trace/SpanContextHolder.java

@@ -16,45 +16,39 @@
 
 package org.springframework.cloud.sleuth.trace;
 
-import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
-import org.springframework.core.NamedThreadLocal;
-
 import lombok.extern.apachecommons.CommonsLog;
+import org.springframework.cloud.sleuth.Span;
+import org.springframework.core.NamedThreadLocal;
 
 /**
  * @author Spencer Gibb
  */
 @CommonsLog
-public class TraceContextHolder {
+public class SpanContextHolder {
 
-	private static final ThreadLocal<Trace> currentTrace = new NamedThreadLocal<>("Trace Context");
-
-	public static Trace getCurrentTrace() {
-		return currentTrace.get();
-	}
+	private static final ThreadLocal<Span> CURRENT_SPAN = new NamedThreadLocal<>("Trace Context");
 
 	public static Span getCurrentSpan() {
-		return isTracing() ? currentTrace.get().getSpan() : null;
+		return isTracing() ? CURRENT_SPAN.get() : null;
 	}
 
-	public static void setCurrentTrace(Trace trace) {
+	public static void setCurrentSpan(Span span) {
 		// backwards compatibility
-		if (trace == null) {
-			currentTrace.remove();
+		if (span == null) {
+			CURRENT_SPAN.remove();
 			return;
 		}
 		if (log.isTraceEnabled()) {
-			log.trace("Setting current trace " + trace);
+			log.trace("Setting current span " + span);
 		}
-		currentTrace.set(trace);
+		CURRENT_SPAN.set(span);
 	}
 
-	public static void removeCurrentTrace() {
-		currentTrace.remove();
+	public static void removeCurrentSpan() {
+		CURRENT_SPAN.remove();
 	}
 
 	public static boolean isTracing() {
-		return currentTrace.get() != null;
+		return CURRENT_SPAN.get() != null;
 	}
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/DefaultTraceManagerTests.java

@@ -25,7 +25,7 @@ import org.springframework.cloud.sleuth.event.SpanReleasedEvent;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.sampler.IsTracingSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationEventPublisher;
 
@@ -53,12 +53,12 @@ public class DefaultTraceManagerTests {
 
 	@Before
 	public void setup() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@After
 	public void clean() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@Test
@@ -67,7 +67,7 @@ public class DefaultTraceManagerTests {
 
 		DefaultTracer traceManager = new DefaultTracer(new IsTracingSampler(), new Random(), publisher);
 
-		Trace trace = traceManager.startTrace(CREATE_SIMPLE_TRACE, new AlwaysSampler());
+		Span trace = traceManager.startTrace(CREATE_SIMPLE_TRACE, new AlwaysSampler());
 		try {
 			importantWork1(traceManager);
 		}
@@ -122,7 +122,7 @@ public class DefaultTraceManagerTests {
 	}
 
 	private void importantWork1(Tracer tracer) {
-		Trace cur = tracer.startTrace(IMPORTANT_WORK_1);
+		Span cur = tracer.startTrace(IMPORTANT_WORK_1);
 		try {
 			Thread.sleep((long) (50 * Math.random()));
 			importantWork2(tracer);
@@ -136,7 +136,7 @@ public class DefaultTraceManagerTests {
 	}
 
 	private void importantWork2(Tracer tracer) {
-		Trace cur = tracer.startTrace(IMPORTANT_WORK_2);
+		Span cur = tracer.startTrace(IMPORTANT_WORK_2);
 		try {
 			Thread.sleep((long) (50 * Math.random()));
 		}

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/TraceCallableTests.java

@@ -5,11 +5,11 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mockito;
 import org.mockito.runners.MockitoJUnitRunner;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEventPublisher;
 
 import java.util.Random;
@@ -28,21 +28,21 @@ public class TraceCallableTests {
 
 	@After
 	public void clean() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@Test
 	public void should_not_see_same_trace_id_in_successive_tasks()
 			throws Exception {
-		Trace firstTrace = givenCallableGetsSubmitted(
+		Span firstTrace = givenCallableGetsSubmitted(
 				thatRetrievesTraceFromThreadLocal());
 
-		Trace secondTrace = whenCallableGetsSubmitted(
+		Span secondTrace = whenCallableGetsSubmitted(
 				thatRetrievesTraceFromThreadLocal());
 
-		then(secondTrace.getSpan().getTraceId())
-				.isNotEqualTo(firstTrace.getSpan().getTraceId());
-		then(secondTrace.getSaved()).isNull();
+		then(secondTrace.getTraceId())
+				.isNotEqualTo(firstTrace.getTraceId());
+		then(secondTrace.getSavedSpan()).isNull();
 	}
 
 	@Test
@@ -50,7 +50,7 @@ public class TraceCallableTests {
 			throws Exception {
 		givenCallableGetsSubmitted(thatRetrievesTraceFromThreadLocal());
 
-		Trace secondTrace = whenNonTraceableCallableGetsSubmitted(
+		Span secondTrace = whenNonTraceableCallableGetsSubmitted(
 				thatRetrievesTraceFromThreadLocal());
 
 		then(secondTrace).isNull();
@@ -59,42 +59,42 @@ public class TraceCallableTests {
 	@Test
 	public void should_remove_parent_span_from_thread_local_after_finishing_work()
 			throws Exception {
-		Trace parent = givenSpanIsAlreadyActive();
-		Trace child = givenCallableGetsSubmitted(thatRetrievesTraceFromThreadLocal());
+		Span parent = givenSpanIsAlreadyActive();
+		Span child = givenCallableGetsSubmitted(thatRetrievesTraceFromThreadLocal());
 		then(parent).as("parent").isNotNull();
-		then(child.getSaved()).isEqualTo(parent);
+		then(child.getSavedSpan()).isEqualTo(parent);
 
-		Trace secondTrace = whenNonTraceableCallableGetsSubmitted(
+		Span secondTrace = whenNonTraceableCallableGetsSubmitted(
 				thatRetrievesTraceFromThreadLocal());
 
 		then(secondTrace).isNull();
 	}
 
-	private Trace givenSpanIsAlreadyActive() {
+	private Span givenSpanIsAlreadyActive() {
 		return this.tracer.startTrace("parent");
 	}
 
-	private Callable<Trace> thatRetrievesTraceFromThreadLocal() {
-		return new Callable<Trace>() {
+	private Callable<Span> thatRetrievesTraceFromThreadLocal() {
+		return new Callable<Span>() {
 			@Override
-			public Trace call() throws Exception {
-				return TraceContextHolder.getCurrentTrace();
+			public Span call() throws Exception {
+				return SpanContextHolder.getCurrentSpan();
 			}
 		};
 	}
 
-	private Trace givenCallableGetsSubmitted(Callable<Trace> callable)
+	private Span givenCallableGetsSubmitted(Callable<Span> callable)
 			throws InterruptedException, java.util.concurrent.ExecutionException {
 		return whenCallableGetsSubmitted(callable);
 	}
 
-	private Trace whenCallableGetsSubmitted(Callable<Trace> callable)
+	private Span whenCallableGetsSubmitted(Callable<Span> callable)
 			throws InterruptedException, java.util.concurrent.ExecutionException {
 		return this.executor.submit(new TraceCallable<>(this.tracer, callable))
 				.get();
 	}
 
-	private Trace whenNonTraceableCallableGetsSubmitted(Callable<Trace> callable)
+	private Span whenNonTraceableCallableGetsSubmitted(Callable<Span> callable)
 			throws InterruptedException, java.util.concurrent.ExecutionException {
 		return this.executor.submit(callable).get();
 	}

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/hystrix/SpanPassingForHystrixViaAnnotationsIntegrationTests.java

@@ -11,7 +11,7 @@ import org.springframework.cloud.netflix.hystrix.EnableHystrix;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -39,7 +39,7 @@ public class SpanPassingForHystrixViaAnnotationsIntegrationTests {
 	}
 
 	private Span givenASpanInCurrentThread() {
-		Span span = tracer.startTrace("existing").getSpan();
+		Span span = tracer.startTrace("existing");
 		tracer.continueSpan(span);
 		return span;
 	}
@@ -61,7 +61,7 @@ public class SpanPassingForHystrixViaAnnotationsIntegrationTests {
 
 	@After
 	public void cleanTrace() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@DefaultTestAutoConfiguration
@@ -81,7 +81,7 @@ public class SpanPassingForHystrixViaAnnotationsIntegrationTests {
 
 		@HystrixCommand
 		public void invokeLogicWrappedInHystrixCommand() {
-			spanCaughtFromHystrixThread = new AtomicReference<>(TraceContextHolder.getCurrentSpan());
+			spanCaughtFromHystrixThread = new AtomicReference<>(SpanContextHolder.getCurrentSpan());
 		}
 
 		public Long getTraceId() {

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/hystrix/TraceCommandTests.java

@@ -7,11 +7,11 @@ import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mockito;
 import org.springframework.cloud.sleuth.MilliSpan;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEventPublisher;
 
 import java.util.Random;
@@ -28,64 +28,64 @@ public class TraceCommandTests {
 
 	@Before
 	public void setup() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@After
 	public void cleanup() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@Test
 	public void should_remove_span_from_thread_local_after_finishing_work()
 			throws Exception {
-		TraceContextHolder.removeCurrentTrace();
-		Trace firstTraceFromHystrix = givenACommandWasExecuted(traceReturningCommand());
+		SpanContextHolder.removeCurrentSpan();
+		Span firstTraceFromHystrix = givenACommandWasExecuted(traceReturningCommand());
 
-		Trace secondTraceFromHystrix = whenCommandIsExecuted(traceReturningCommand());
+		Span secondTraceFromHystrix = whenCommandIsExecuted(traceReturningCommand());
 
-		then(secondTraceFromHystrix.getSpan().getTraceId()).as("second trace id")
-				.isNotEqualTo(firstTraceFromHystrix.getSpan().getTraceId()).as("first trace id");
-		then(secondTraceFromHystrix.getSaved()).as("saved trace as remnant of first trace")
+		then(secondTraceFromHystrix.getTraceId()).as("second trace id")
+				.isNotEqualTo(firstTraceFromHystrix.getTraceId()).as("first trace id");
+		then(secondTraceFromHystrix.getSavedSpan()).as("saved trace as remnant of first trace")
 				.isNull();
 	}
 
 	@Test
 	public void should_run_Hystrix_command_with_span_passed_from_parent_thread() {
 		givenATraceIsPresentInTheCurrentThread();
-		TraceCommand<Trace> command = traceReturningCommand();
+		TraceCommand<Span> command = traceReturningCommand();
 
-		Trace traceFromCommand = whenCommandIsExecuted(command);
+		Span traceFromCommand = whenCommandIsExecuted(command);
 
-		then(traceFromCommand).as("Trace from the Hystrix Thread").isNotNull();
-		then(traceFromCommand.getSpan().getTraceId()).isEqualTo(EXPECTED_TRACE_ID);
+		then(traceFromCommand).as("Span from the Hystrix Thread").isNotNull();
+		then(traceFromCommand.getTraceId()).isEqualTo(EXPECTED_TRACE_ID);
 	}
 
 	@After
 	public void cleanUpTrace() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
-	private Trace givenATraceIsPresentInTheCurrentThread() {
+	private Span givenATraceIsPresentInTheCurrentThread() {
 		return this.tracer.joinTrace("test", MilliSpan.builder().traceId(EXPECTED_TRACE_ID).build());
 	}
 
-	private TraceCommand<Trace> traceReturningCommand() {
-		return new TraceCommand<Trace>(this.tracer,  withGroupKey(asKey(""))
+	private TraceCommand<Span> traceReturningCommand() {
+		return new TraceCommand<Span>(this.tracer,  withGroupKey(asKey(""))
 				.andCommandKey(HystrixCommandKey.Factory.asKey("")).andThreadPoolPropertiesDefaults(
 						HystrixThreadPoolProperties.Setter().withMaxQueueSize(1).withCoreSize(1))) {
 			@Override
-			public Trace doRun() throws Exception {
-				return TraceContextHolder.getCurrentTrace();
+			public Span doRun() throws Exception {
+				return SpanContextHolder.getCurrentSpan();
 			}
 		};
 	}
 
-	private Trace whenCommandIsExecuted(TraceCommand<Trace> command) {
+	private Span whenCommandIsExecuted(TraceCommand<Span> command) {
 		return command.execute();
 	}
 
-	private Trace givenACommandWasExecuted(TraceCommand<Trace> command) {
+	private Span givenACommandWasExecuted(TraceCommand<Span> command) {
 		return whenCommandIsExecuted(command);
 	}
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/integration/TraceChannelInterceptorTests.java

@@ -26,12 +26,11 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.IntegrationTest;
 import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.event.SpanReleasedEvent;
 import org.springframework.cloud.sleuth.instrument.integration.TraceChannelInterceptorTests.App;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.event.EventListener;
@@ -79,7 +78,7 @@ public class TraceChannelInterceptorTests implements MessageHandler {
 	@Override
 	public void handleMessage(Message<?> message) throws MessagingException {
 		this.message = message;
-		this.span = TraceContextHolder.getCurrentSpan();
+		this.span = SpanContextHolder.getCurrentSpan();
 	}
 
 	@Before
@@ -89,35 +88,35 @@ public class TraceChannelInterceptorTests implements MessageHandler {
 
 	@After
 	public void close() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 		this.channel.unsubscribe(this);
 	}
 
 	@Test
 	public void nonExportableSpanCreation() {
-		this.channel.send(MessageBuilder.withPayload("hi").setHeader(Trace.NOT_SAMPLED_NAME, "")
+		this.channel.send(MessageBuilder.withPayload("hi").setHeader(Span.NOT_SAMPLED_NAME, "")
 				.build());
 		assertNotNull("message was null", this.message);
 
-		String spanId = this.message.getHeaders().get(Trace.SPAN_ID_NAME, String.class);
+		String spanId = this.message.getHeaders().get(Span.SPAN_ID_NAME, String.class);
 		assertNotNull("spanId was null", spanId);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 		assertFalse(this.span.isExportable());
 	}
 
 	@Test
 	public void parentSpanIncluded() {
-		this.channel.send(MessageBuilder.withPayload("hi").setHeader(Trace.TRACE_ID_NAME, 10L)
-				.setHeader(Trace.SPAN_ID_NAME, 20L)
+		this.channel.send(MessageBuilder.withPayload("hi").setHeader(Span.TRACE_ID_NAME, 10L)
+				.setHeader(Span.SPAN_ID_NAME, 20L)
 				.build());
 		assertNotNull("message was null", this.message);
 
-		String spanId = this.message.getHeaders().get(Trace.SPAN_ID_NAME, String.class);
+		String spanId = this.message.getHeaders().get(Span.SPAN_ID_NAME, String.class);
 		assertNotNull("spanId was null", spanId);
-		long traceId = Span.IdConverter.fromHex(this.message.getHeaders().get(Trace.TRACE_ID_NAME, String.class));
+		long traceId = Span.IdConverter.fromHex(this.message.getHeaders().get(Span.TRACE_ID_NAME, String.class));
 		then(traceId).isEqualTo(10L);
 		then(spanId).isNotEqualTo(20L);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 		assertEquals(1, this.app.events.size());
 	}
 
@@ -126,45 +125,45 @@ public class TraceChannelInterceptorTests implements MessageHandler {
 		this.channel.send(MessageBuilder.withPayload("hi").build());
 		assertNotNull("message was null", this.message);
 
-		String spanId = this.message.getHeaders().get(Trace.SPAN_ID_NAME, String.class);
+		String spanId = this.message.getHeaders().get(Span.SPAN_ID_NAME, String.class);
 		assertNotNull("spanId was null", spanId);
 
-		String traceId = this.message.getHeaders().get(Trace.TRACE_ID_NAME, String.class);
+		String traceId = this.message.getHeaders().get(Span.TRACE_ID_NAME, String.class);
 		assertNotNull("traceId was null", traceId);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void headerCreation() {
-		Trace trace = this.tracer.startTrace("testSendMessage",
+		Span trace = this.tracer.startTrace("testSendMessage",
 				new AlwaysSampler());
 		this.channel.send(MessageBuilder.withPayload("hi").build());
 		this.tracer.close(trace);
 		assertNotNull("message was null", this.message);
 
-		String spanId = this.message.getHeaders().get(Trace.SPAN_ID_NAME, String.class);
+		String spanId = this.message.getHeaders().get(Span.SPAN_ID_NAME, String.class);
 		assertNotNull("spanId was null", spanId);
 
-		String traceId = this.message.getHeaders().get(Trace.TRACE_ID_NAME, String.class);
+		String traceId = this.message.getHeaders().get(Span.TRACE_ID_NAME, String.class);
 		assertNotNull("traceId was null", traceId);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	// TODO: Refactor to parametrized test together with sending messages via channel
 	@Test
 	public void headerCreationViaMessagingTemplate() {
-		Trace trace = this.tracer.startTrace("testSendMessage",
+		Span trace = this.tracer.startTrace("testSendMessage",
 				new AlwaysSampler());
 		this.messagingTemplate.send(MessageBuilder.withPayload("hi").build());
 		this.tracer.close(trace);
 		assertNotNull("message was null", this.message);
 
-		String spanId = this.message.getHeaders().get(Trace.SPAN_ID_NAME, String.class);
+		String spanId = this.message.getHeaders().get(Span.SPAN_ID_NAME, String.class);
 		assertNotNull("spanId was null", spanId);
 
-		String traceId = this.message.getHeaders().get(Trace.TRACE_ID_NAME, String.class);
+		String traceId = this.message.getHeaders().get(Span.TRACE_ID_NAME, String.class);
 		assertNotNull("traceId was null", traceId);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Configuration

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/integration/TraceContextPropagationChannelInterceptorTests.java

@@ -25,11 +25,10 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.IntegrationTest;
 import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.integration.TraceContextPropagationChannelInterceptorTests.App;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.integration.channel.QueueChannel;
@@ -60,25 +59,25 @@ public class TraceContextPropagationChannelInterceptorTests {
 
 	@After
 	public void close() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@Test
 	public void testSpanPropagation() {
 
-		Trace trace = this.tracer.startTrace("testSendMessage", new AlwaysSampler());
+		Span trace = this.tracer.startTrace("testSendMessage", new AlwaysSampler());
 		this.channel.send(MessageBuilder.withPayload("hi").build());
-		Long expectedSpanId = trace.getSpan().getSpanId();
+		Long expectedSpanId = trace.getSpanId();
 		this.tracer.close(trace);
 
 		Message<?> message = this.channel.receive(0);
 
 		assertNotNull("message was null", message);
 
-		Long spanId = Span.IdConverter.fromHex(message.getHeaders().get(Trace.SPAN_ID_NAME, String.class));
+		Long spanId = Span.IdConverter.fromHex(message.getHeaders().get(Span.SPAN_ID_NAME, String.class));
 		assertEquals("spanId was wrong", expectedSpanId,  spanId);
 
-		long traceId = Span.IdConverter.fromHex(message.getHeaders().get(Trace.TRACE_ID_NAME, String.class));
+		long traceId = Span.IdConverter.fromHex(message.getHeaders().get(Span.TRACE_ID_NAME, String.class));
 		assertNotNull("traceId was null", traceId);
 	}
 

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/integration/TraceStompMessageChannelInterceptorTests.java

@@ -6,10 +6,10 @@ import org.junit.Test;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.IntegrationTest;
 import org.springframework.boot.test.SpringApplicationConfiguration;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.instrument.integration.TraceStompMessageChannelInterceptorTests.TestApplication;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.messaging.Message;
@@ -44,12 +44,12 @@ public class TraceStompMessageChannelInterceptorTests extends AbstractTraceStomp
 
 		thenSpanIdFromHeadersIsNotEmpty();
 		thenTraceIdFromHeadersIsNotEmpty();
-		then(TraceContextHolder.getCurrentTrace()).isNull();
+		then(SpanContextHolder.getCurrentSpan()).isNull();
 	}
 
 	@Test
 	public void should_propagate_headers_when_message_was_sent_during_local_span_starting() {
-		Trace trace = givenALocallyStartedSpan();
+		Span trace = givenALocallyStartedSpan();
 		Message<?> message = givenMessageToBeSampled();
 
 		whenTheMessageWasSent(message);
@@ -57,17 +57,17 @@ public class TraceStompMessageChannelInterceptorTests extends AbstractTraceStomp
 
 		Long spanId = thenSpanIdFromHeadersIsNotEmpty();
 		long traceId = thenTraceIdFromHeadersIsNotEmpty();
-		then(traceId).isEqualTo(trace.getSpan().getTraceId());
-		then(spanId).isEqualTo(trace.getSpan().getSpanId());
-		then(TraceContextHolder.getCurrentTrace()).isNull();
+		then(traceId).isEqualTo(trace.getTraceId());
+		then(spanId).isEqualTo(trace.getSpanId());
+		then(SpanContextHolder.getCurrentSpan()).isNull();
 	}
 
 	private Message<?> givenMessageNotToBeSampled() {
-		return StompMessageBuilder.fromMessage(new GenericMessage<>("Message2")).setHeader(Trace.NOT_SAMPLED_NAME, "").build();
+		return StompMessageBuilder.fromMessage(new GenericMessage<>("Message2")).setHeader(Span.NOT_SAMPLED_NAME, "").build();
 	}
 
 	private String thenSpanIdFromHeadersIsEmpty() {
-		String header = getValueFromHeaders(Trace.SPAN_ID_NAME, String.class);
+		String header = getValueFromHeaders(Span.SPAN_ID_NAME, String.class);
 		then(header).as("Span id should be empty").isNullOrEmpty();
 		return header;
 	}

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/integration/TraceStompMessageContextPropagationChannelInterceptorTests.java

@@ -7,7 +7,7 @@ import org.junit.runner.RunWith;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.IntegrationTest;
 import org.springframework.boot.test.SpringApplicationConfiguration;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.instrument.integration.TraceStompMessageContextPropagationChannelInterceptorTests.TestApplication;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.context.annotation.Bean;
@@ -28,11 +28,11 @@ public class TraceStompMessageContextPropagationChannelInterceptorTests extends
 
 	@Test
 	public void should_propagate_span_information() {
-		Trace trace = givenALocallyStartedSpan();
+		Span trace = givenALocallyStartedSpan();
 		Message<?> m = givenMessageToBeSampled();
 
 		whenTheMessageWasSent(m);
-		Long expectedTraceId = trace.getSpan().getTraceId();
+		Long expectedTraceId = trace.getTraceId();
 		this.tracer.close(trace);
 
 		thenReceivedMessageIsNotNull();

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/scheduling/TracingOnScheduledTests.java

@@ -9,7 +9,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.scheduling.annotation.Scheduled;
@@ -70,7 +70,7 @@ class TestBeanWithScheduledMethod {
 
 	@Scheduled(fixedDelay = 1L)
 	public void scheduledMethod() {
-		this.span = TraceContextHolder.getCurrentSpan();
+		this.span = SpanContextHolder.getCurrentSpan();
 	}
 
 	public Span getSpan() {

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/RestTemplateTraceAspectIntegrationTests.java

@@ -9,7 +9,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.SpringApplicationConfiguration;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
 import org.springframework.cloud.sleuth.instrument.web.common.HttpMockServer;
 import org.springframework.cloud.sleuth.instrument.web.common.AbstractMvcWiremockIntegrationTest;
@@ -71,7 +71,7 @@ public class RestTemplateTraceAspectIntegrationTests extends AbstractMvcWiremock
 	}
 
 	private void thenTraceIdHasBeenSetOnARequestHeader() {
-		this.wireMock.verifyThat(getRequestedFor(urlMatching(".*")).withHeader(Trace.TRACE_ID_NAME, matching("^(?!\\s*$).+")));
+		this.wireMock.verifyThat(getRequestedFor(urlMatching(".*")).withHeader(Span.TRACE_ID_NAME, matching("^(?!\\s*$).+")));
 	}
 
 	private void whenARequestIsSentToAnAsyncEndpoint(String url) throws Exception {

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceAsyncIntegrationTests.java

@@ -10,7 +10,7 @@ import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.scheduling.annotation.Async;
@@ -40,7 +40,7 @@ public class TraceAsyncIntegrationTests {
 	}
 
 	private Span givenASpanInCurrentThread() {
-		Span span = tracer.startTrace("existing").getSpan();
+		Span span = tracer.startTrace("existing");
 		tracer.continueSpan(span);
 		return span;
 	}
@@ -62,7 +62,7 @@ public class TraceAsyncIntegrationTests {
 
 	@After
 	public void cleanTrace() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@DefaultTestAutoConfiguration
@@ -83,7 +83,7 @@ public class TraceAsyncIntegrationTests {
 
 		@Async
 		public void invokeAsynchronousLogic() {
-			span.set(TraceContextHolder.getCurrentSpan());
+			span.set(SpanContextHolder.getCurrentSpan());
 		}
 
 		public Long getTraceId() {

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceFilterIntegrationTests.java

@@ -9,7 +9,6 @@ import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
 import org.springframework.cloud.sleuth.instrument.TraceKeys;
@@ -60,7 +59,7 @@ public class TraceFilterIntegrationTests extends AbstractMvcIntegrationTest {
 
 	private MvcResult whenSentPingWithTraceId(Long passedTraceId)
 			throws Exception {
-		return sendPingWithTraceId(Trace.TRACE_ID_NAME, passedTraceId);
+		return sendPingWithTraceId(Span.TRACE_ID_NAME, passedTraceId);
 	}
 
 	private MvcResult sendPingWithTraceId(String headerName, Long passedCorrelationId)
@@ -68,11 +67,11 @@ public class TraceFilterIntegrationTests extends AbstractMvcIntegrationTest {
 		return this.mockMvc
 				.perform(MockMvcRequestBuilders.get("/ping").accept(MediaType.TEXT_PLAIN)
 						.header(headerName, Span.IdConverter.toHex(passedCorrelationId))
-						.header(Trace.SPAN_ID_NAME, Span.IdConverter.toHex(new Random().nextLong())))
+						.header(Span.SPAN_ID_NAME, Span.IdConverter.toHex(new Random().nextLong())))
 				.andReturn();
 	}
 
 	private Long tracingHeaderFrom(MvcResult mvcResult) {
-		return Span.IdConverter.fromHex(mvcResult.getResponse().getHeader(Trace.TRACE_ID_NAME));
+		return Span.IdConverter.fromHex(mvcResult.getResponse().getHeader(Span.TRACE_ID_NAME));
 	}
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceFilterMockChainIntegrationTests.java

@@ -16,19 +16,15 @@
 
 package org.springframework.cloud.sleuth.instrument.web;
 
-import static org.junit.Assert.assertNull;
-import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
-
-import java.util.Random;
-
+import lombok.SneakyThrows;
 import org.junit.Before;
 import org.junit.Test;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.TraceKeys;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.http.MediaType;
 import org.springframework.mock.web.MockFilterChain;
@@ -37,7 +33,10 @@ import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 
-import lombok.SneakyThrows;
+import java.util.Random;
+
+import static org.junit.Assert.assertNull;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 
 /**
  * @author Spencer Gibb
@@ -58,7 +57,7 @@ public class TraceFilterMockChainIntegrationTests {
 	@Before
 	@SneakyThrows
 	public void init() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 		this.context.refresh();
 		this.request = builder().buildRequest(new MockServletContext());
 		this.response = new MockHttpServletResponse();
@@ -75,17 +74,17 @@ public class TraceFilterMockChainIntegrationTests {
 	public void startsNewTrace() throws Exception {
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
 		filter.doFilter(this.request, this.response, this.filterChain);
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void continuesSpanFromHeaders() throws Exception {
 		Random generator = new Random();
-		this.request = builder().header(Trace.SPAN_ID_NAME, generator.nextLong())
-				.header(Trace.TRACE_ID_NAME, generator.nextLong()).buildRequest(new MockServletContext());
+		this.request = builder().header(Span.SPAN_ID_NAME, generator.nextLong())
+				.header(Span.TRACE_ID_NAME, generator.nextLong()).buildRequest(new MockServletContext());
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
 		filter.doFilter(this.request, this.response, this.filterChain);
-		assertNull(TraceContextHolder.getCurrentSpan());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceFilterTests.java

@@ -16,28 +16,18 @@
 
 package org.springframework.cloud.sleuth.instrument.web;
 
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.entry;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.mockito.MockitoAnnotations.initMocks;
-import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
-
-import java.util.Random;
-
+import lombok.SneakyThrows;
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mock;
 import org.springframework.cloud.sleuth.Sampler;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.instrument.TraceKeys;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.sampler.IsTracingSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
@@ -47,7 +37,15 @@ import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
 
-import lombok.SneakyThrows;
+import java.util.Random;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.mockito.MockitoAnnotations.initMocks;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 
 /**
  * @author Spencer Gibb
@@ -74,9 +72,9 @@ public class TraceFilterTests {
 		this.tracer = new DefaultTracer(new DelegateSampler(), new Random(),
 				this.publisher) {
 			@Override
-			protected Trace createTrace(Trace trace, Span span) {
-				TraceFilterTests.this.span = span;
-				return super.createTrace(trace, span);
+			protected Span createSpan(Span trace, Span span) {
+				TraceFilterTests.this.span = super.createSpan(trace, span);
+				return TraceFilterTests.this.span;
 			}
 		};
 		this.request = builder().buildRequest(new MockServletContext());
@@ -101,7 +99,7 @@ public class TraceFilterTests {
 		filter.doFilter(this.request, this.response, this.filterChain);
 
 		assertFalse(this.span.isExportable());
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
@@ -109,13 +107,13 @@ public class TraceFilterTests {
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
 		filter.doFilter(this.request, this.response, this.filterChain);
 		verifyHttpTags();
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void continuesSpanInRequestAttr() throws Exception {
 
-		Trace trace = this.tracer.startTrace("foo");
+		Span trace = this.tracer.startTrace("foo");
 		this.request.setAttribute(TraceFilter.TRACE_REQUEST_ATTR, trace);
 
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
@@ -123,26 +121,26 @@ public class TraceFilterTests {
 
 		verifyHttpTags();
 
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void continuesSpanFromHeaders() throws Exception {
-		this.request = builder().header(Trace.SPAN_ID_NAME, 10L)
-				.header(Trace.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
+		this.request = builder().header(Span.SPAN_ID_NAME, 10L)
+				.header(Span.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
 
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
 		filter.doFilter(this.request, this.response, this.filterChain);
 
 		verifyHttpTags();
 
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void addsAdditionalHeaders() throws Exception {
-		this.request = builder().header(Trace.SPAN_ID_NAME, 10L)
-				.header(Trace.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
+		this.request = builder().header(Span.SPAN_ID_NAME, 10L)
+				.header(Span.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
 
 		this.traceKeys.getHttp().getHeaders().add("x-foo");
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
@@ -151,13 +149,13 @@ public class TraceFilterTests {
 
 		assertThat(this.span.tags()).contains(entry("http/x-foo", "bar"));
 
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
 	public void additionalMultiValuedHeader() throws Exception {
-		this.request = builder().header(Trace.SPAN_ID_NAME, 10L)
-				.header(Trace.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
+		this.request = builder().header(Span.SPAN_ID_NAME, 10L)
+				.header(Span.TRACE_ID_NAME, 20L).buildRequest(new MockServletContext());
 
 		this.traceKeys.getHttp().getHeaders().add("x-foo");
 		TraceFilter filter = new TraceFilter(this.tracer, this.traceKeys);
@@ -167,7 +165,7 @@ public class TraceFilterTests {
 
 		assertThat(this.span.tags()).contains(entry("http/x-foo", "'bar','spam'"));
 
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	@Test
@@ -189,7 +187,7 @@ public class TraceFilterTests {
 		}
 		verifyHttpTags(HttpStatus.INTERNAL_SERVER_ERROR);
 
-		assertNull(TraceContextHolder.getCurrentTrace());
+		assertNull(SpanContextHolder.getCurrentSpan());
 	}
 
 	public void verifyHttpTags() {

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/template/TraceTemplateTests.java

@@ -1,19 +1,19 @@
 package org.springframework.cloud.sleuth.template;
 
-import static org.assertj.core.api.BDDAssertions.then;
-
-import java.util.Random;
-
 import org.junit.After;
 import org.junit.Test;
 import org.mockito.Mockito;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
 import org.springframework.cloud.sleuth.trace.DefaultTracer;
-import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.cloud.sleuth.trace.SpanContextHolder;
 import org.springframework.context.ApplicationEventPublisher;
 
+import java.util.Random;
+
+import static org.assertj.core.api.BDDAssertions.then;
+
 public class TraceTemplateTests {
 
 	Tracer tracer = new DefaultTracer(new AlwaysSampler(),
@@ -21,25 +21,25 @@ public class TraceTemplateTests {
 
 	@After
 	public void close() {
-		TraceContextHolder.removeCurrentTrace();
+		SpanContextHolder.removeCurrentSpan();
 	}
 
 	@Test
 	public void should_pass_trace_to_the_callback_if_tracing_is_active() {
-		Trace initialTrace = this.tracer.startTrace("test");
+		Span initialTrace = this.tracer.startTrace("test");
 		TraceTemplate traceTemplate = new TraceTemplate(this.tracer);
 
-		Trace traceFromCallback = whenTraceCallbackReturningCurrentTraceIsExecuted(traceTemplate);
+		Span traceFromCallback = whenTraceCallbackReturningCurrentTraceIsExecuted(traceTemplate);
 
 		then(traceFromCallback).isNotNull();
-		then(traceFromCallback.getSpan().getTraceId()).isEqualTo(initialTrace.getSpan().getTraceId());
+		then(traceFromCallback.getTraceId()).isEqualTo(initialTrace.getTraceId());
 	}
 
-	private Trace whenTraceCallbackReturningCurrentTraceIsExecuted(TraceTemplate traceTemplate) {
-		return traceTemplate.trace(new TraceCallback<Trace>() {
+	private Span whenTraceCallbackReturningCurrentTraceIsExecuted(TraceTemplate traceTemplate) {
+		return traceTemplate.trace(new TraceCallback<Span>() {
 				@Override
-				public Trace doInTrace(Trace trace) {
-					return TraceContextHolder.getCurrentTrace();
+				public Span doInTrace(Span trace) {
+					return SpanContextHolder.getCurrentSpan();
 				}
 			});
 	}

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-stream/src/main/java/sample/SampleController.java

@@ -21,7 +21,6 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
@@ -94,7 +93,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 	@SneakyThrows
 	@RequestMapping("/traced")
 	public String traced() {
-		Trace trace = this.tracer.startTrace("customTraceEndpoint",
+		Span trace = this.tracer.startTrace("customTraceEndpoint",
 				new AlwaysSampler());
 		int millis = random.nextInt(1000);
 		log.info("Sleeping for {} millis", millis);

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-test-core/src/main/java/tools/RequestSendingRunnable.java

@@ -17,7 +17,6 @@ package tools;
 
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.http.*;
 import org.springframework.web.client.RestTemplate;
 
@@ -53,7 +52,7 @@ public class RequestSendingRunnable implements Runnable {
 
 	private RequestEntity requestWithTraceId(long traceId) {
 		HttpHeaders headers = new HttpHeaders();
-		headers.add(Trace.TRACE_ID_NAME, Span.IdConverter.toHex(traceId));
+		headers.add(Span.TRACE_ID_NAME, Span.IdConverter.toHex(traceId));
 		URI uri = URI.create(url);
 		RequestEntity requestEntity = new RequestEntity<>(headers, HttpMethod.GET, uri);
 		log.info("Request [" + requestEntity + "] is ready");

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/java/sample/SampleController.java

@@ -21,7 +21,6 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
@@ -94,7 +93,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 	@SneakyThrows
 	@RequestMapping("/traced")
 	public String traced() {
-		Trace trace = this.tracer.startTrace("customTraceEndpoint",
+		Span trace = this.tracer.startTrace("customTraceEndpoint",
 				new AlwaysSampler());
 		int millis = random.nextInt(1000);
 		log.info("Sleeping for {} millis", millis);

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample/src/main/java/sample/SampleController.java

@@ -21,7 +21,6 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceAccessor;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
@@ -94,7 +93,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 	@SneakyThrows
 	@RequestMapping("/traced")
 	public String traced() {
-		Trace trace = this.tracer.startTrace("customTraceEndpoint",
+		Span trace = this.tracer.startTrace("customTraceEndpoint",
 				new AlwaysSampler());
 		int millis = random.nextInt(1000);
 		log.info("Sleeping for {} millis", millis);

spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/SleuthStreamAutoConfiguration.java

@@ -25,7 +25,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.client.discovery.DiscoveryClient;
-import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.stream.annotation.EnableBinding;
 import org.springframework.cloud.stream.config.ChannelBindingAutoConfiguration;
 import org.springframework.context.annotation.Bean;
@@ -61,7 +61,7 @@ public class SleuthStreamAutoConfiguration {
 			@Override
 			public Message<?> preSend(Message<?> message, MessageChannel channel) {
 				return MessageBuilder.fromMessage(message)
-						.setHeader(Trace.NOT_SAMPLED_NAME, "").build();
+						.setHeader(Span.NOT_SAMPLED_NAME, "").build();
 			}
 		};
 	}

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanListenerTests.java

@@ -31,7 +31,6 @@ import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.MilliSpan;
 import org.springframework.cloud.sleuth.Sampler;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration;
 import org.springframework.cloud.sleuth.event.ClientReceivedEvent;
@@ -78,7 +77,7 @@ public class StreamSpanListenerTests {
 
 	@Test
 	public void acquireAndRelease() {
-		Trace context = this.tracer.startTrace("foo");
+		Span context = this.tracer.startTrace("foo");
 		this.tracer.close(context);
 		assertEquals(1, this.test.spans.size());
 	}
@@ -87,21 +86,21 @@ public class StreamSpanListenerTests {
 	public void rpcAnnotations() {
 		Span parent = MilliSpan.builder().traceId(1L).name("parent").remote(true)
 				.build();
-		Trace context = this.tracer.joinTrace("child", parent);
-		this.application.publishEvent(new ClientSentEvent(this, context.getSpan()));
+		Span context = this.tracer.joinTrace("child", parent);
+		this.application.publishEvent(new ClientSentEvent(this, context));
 		this.application
-				.publishEvent(new ServerReceivedEvent(this, parent, context.getSpan()));
+				.publishEvent(new ServerReceivedEvent(this, parent, context));
 		this.application
-				.publishEvent(new ServerSentEvent(this, parent, context.getSpan()));
-		this.application.publishEvent(new ClientReceivedEvent(this, context.getSpan()));
+				.publishEvent(new ServerSentEvent(this, parent, context));
+		this.application.publishEvent(new ClientReceivedEvent(this, context));
 		this.tracer.close(context);
 		assertEquals(2, this.test.spans.size());
 	}
 
 	@Test
 	public void nullSpanName() {
-		Trace context = this.tracer.startTrace(null, (Sampler) null);
-		this.application.publishEvent(new ClientSentEvent(this, context.getSpan()));
+		Span context = this.tracer.startTrace(null, (Sampler) null);
+		this.application.publishEvent(new ClientSentEvent(this, context));
 		this.tracer.close(context);
 		assertEquals(1, this.test.spans.size());
 		this.listener.poll();

spring-cloud-sleuth-zipkin/src/test/java/org/springframework/cloud/sleuth/zipkin/ZipkinSpanListenerTests.java

@@ -32,7 +32,6 @@ import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.cloud.sleuth.MilliSpan;
 import org.springframework.cloud.sleuth.Sampler;
 import org.springframework.cloud.sleuth.Span;
-import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.Tracer;
 import org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration;
 import org.springframework.cloud.sleuth.event.ClientReceivedEvent;
@@ -119,7 +118,7 @@ public class ZipkinSpanListenerTests {
 	 */
 	@Test
 	public void spanWithoutAnnotationsLogsComponent() {
-		Trace context = this.tracer.startTrace("foo");
+		Span context = this.tracer.startTrace("foo");
 		this.tracer.close(context);
 		assertEquals(1, this.test.spans.size());
 		assertThat(this.test.spans.get(0).binaryAnnotations.get(0).endpoint.serviceName)
@@ -128,11 +127,11 @@ public class ZipkinSpanListenerTests {
 
 	@Test
 	public void rpcAnnotations() {
-		Trace context = this.tracer.joinTrace("child", parent);
-		this.application.publishEvent(new ClientSentEvent(this, context.getSpan()));
-		this.application.publishEvent(new ServerReceivedEvent(this, parent, context.getSpan()));
-		this.application.publishEvent(new ServerSentEvent(this, parent, context.getSpan()));
-		this.application.publishEvent(new ClientReceivedEvent(this, context.getSpan()));
+		Span context = this.tracer.joinTrace("child", parent);
+		this.application.publishEvent(new ClientSentEvent(this, context));
+		this.application.publishEvent(new ServerReceivedEvent(this, parent, context));
+		this.application.publishEvent(new ServerSentEvent(this, parent, context));
+		this.application.publishEvent(new ClientReceivedEvent(this, context));
 		this.tracer.close(context);
 		assertEquals(2, this.test.spans.size());
 	}