rename SpanHolder to TraceContextHolder

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

@@ -68,7 +68,7 @@ public class DefaultTrace implements Trace {
 	@Override
 	public <T> TraceScope startSpan(String description, Sampler<T> s, T info) {
 		Span span = null;
-		if (isTracing() || s.next(info)) {
+		if (TraceContextHolder.isTracing() || s.next(info)) {
 			span = createNew(description);
 		}
 		return doStart(span);
@@ -114,12 +114,12 @@ public class DefaultTrace implements Trace {
 		// Return an empty TraceScope that does nothing on close
 		if (span == null) return NullScope.INSTANCE;
 		Span oldSpan = getCurrentSpan();
-		SpanHolder.setCurrentSpan(span);
+		TraceContextHolder.setCurrentSpan(span);
 		return new TraceScope(this, span, oldSpan);
 	}
 
 	protected Span getCurrentSpan() {
-		return SpanHolder.getCurrentSpan();
+		return TraceContextHolder.getCurrentSpan();
 	}
 
 	@Override
@@ -130,11 +130,6 @@ public class DefaultTrace implements Trace {
 		}
 	}
 
-	@Override
-	public boolean isTracing() {
-		return getCurrentSpan() != null;
-	}
-
 	//TODO: rename? this is the end of a Span lifecycle
 	@Override
 	public void deliver(Span span) {

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

@@ -77,10 +77,5 @@ public interface Trace {
 	 */
 	void addKVAnnotation(String key, String value);
 
-	/**
-	 * Returns true if the current thread is a part of a trace, false otherwise.
-	 */
-	boolean isTracing();
-
 	void deliver(Span span);
 }

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

@@ -1,13 +1,14 @@
 package org.springframework.cloud.sleuth;
 
 import lombok.extern.apachecommons.CommonsLog;
+import org.springframework.core.NamedThreadLocal;
 
 /**
  * @author Spencer Gibb
  */
 @CommonsLog
-public class SpanHolder {
-	private static final ThreadLocal<Span> currentSpan = new ThreadLocal<>();
+public class TraceContextHolder {
+	private static final ThreadLocal<Span> currentSpan = new NamedThreadLocal<>("Trace Context");
 
 	public static Span getCurrentSpan() {
 		return currentSpan.get();

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

@@ -45,14 +45,14 @@ public class TraceScope implements Closeable {
 		}
 		detached = true;
 
-		Span cur = SpanHolder.getCurrentSpan();
+		Span cur = TraceContextHolder.getCurrentSpan();
 		if (cur != span) {
 			Utils.error("Tried to detach trace span " + span + " but " +
 					"it is not the current span for the " +
 					Thread.currentThread().getName() + " thread.  You have " +
 					"probably forgotten to close or detach " + cur);
 		} else {
-			SpanHolder.setCurrentSpan(savedSpan);
+			TraceContextHolder.setCurrentSpan(savedSpan);
 		}
 		return span;
 	}
@@ -64,7 +64,7 @@ public class TraceScope implements Closeable {
 			return;
 		}
 		detached = true;
-		Span cur = SpanHolder.getCurrentSpan();
+		Span cur = TraceContextHolder.getCurrentSpan();
 		if (cur != span) {
 			Utils.error("Tried to close trace span " + span + " but " +
 					"it is not the current span for the " +
@@ -74,7 +74,7 @@ public class TraceScope implements Closeable {
 			span.stop();
 			//TODO: use ApplicationEvents here?
 			trace.deliver(span);
-			SpanHolder.setCurrentSpan(savedSpan);
+			TraceContextHolder.setCurrentSpan(savedSpan);
 		}
 	}
 

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

@@ -1,7 +1,7 @@
 package org.springframework.cloud.sleuth.sampler;
 
 import org.springframework.cloud.sleuth.Sampler;
-import org.springframework.cloud.sleuth.SpanHolder;
+import org.springframework.cloud.sleuth.TraceContextHolder;
 
 /**
  * @author Spencer Gibb
@@ -10,6 +10,6 @@ public class IsTracingSampler implements Sampler<Object> {
 
 	@Override
 	public boolean next(Object info) {
-		return SpanHolder.getCurrentSpan() != null;
+		return TraceContextHolder.getCurrentSpan() != null;
 	}
 }

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

@@ -17,10 +17,11 @@ package org.springframework.cloud.sleuth.web.client;
 
 import static org.springframework.cloud.sleuth.Trace.SPAN_ID_NAME;
 import static org.springframework.cloud.sleuth.Trace.TRACE_ID_NAME;
+import static org.springframework.cloud.sleuth.TraceContextHolder.getCurrentSpan;
+import static org.springframework.cloud.sleuth.TraceContextHolder.isTracing;
 
 import java.io.IOException;
 
-import org.springframework.cloud.sleuth.SpanHolder;
 import org.springframework.cloud.sleuth.Trace;
 import org.springframework.http.HttpRequest;
 import org.springframework.http.client.ClientHttpRequestExecution;
@@ -42,13 +43,13 @@ public class TraceRestTemplateInterceptor implements ClientHttpRequestIntercepto
 	@Override
 	public ClientHttpResponse intercept(HttpRequest request, byte[] body,
 			ClientHttpRequestExecution execution) throws IOException {
-		setHeader(request, SPAN_ID_NAME, SpanHolder.getCurrentSpan().getSpanId());
-		setHeader(request, TRACE_ID_NAME, SpanHolder.getCurrentSpan().getTraceId());
+		setHeader(request, SPAN_ID_NAME, getCurrentSpan().getSpanId());
+		setHeader(request, TRACE_ID_NAME, getCurrentSpan().getTraceId());
 		return execution.execute(request, body);
 	}
 
 	public void setHeader(HttpRequest request, String spanIdName, String spanId) {
-		if (!request.getHeaders().containsKey(spanIdName) && SpanHolder.isTracing()) {
+		if (!request.getHeaders().containsKey(spanIdName) && isTracing()) {
 			request.getHeaders().add(spanIdName, spanId);
 		}
 	}