Refactor annotations for metric export

Users can add @ExportMetric[Reader,Writer] to readers and writers that
they want to participate in the default exporter. There is also still an
@ActuatorMetricWriter that is used for the legacy (non-Java8) Gauge and
CounterServices.

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/ExportMetricReader.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2015 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.boot.actuate.autoconfigure;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+
+/**
+ * Qualifier annotation for a metric reader that can be exported (to distinguish it from
+ * others that might be installed by the user for other purposes).
+ *
+ * @author Dave Syer
+ */
+@Qualifier
+@Target({ ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE,
+		ElementType.ANNOTATION_TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+@Inherited
+@Documented
+public @interface ExportMetricReader {
+
+}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/ExportMetricWriter.java

@@ -26,8 +26,8 @@ import java.lang.annotation.Target;
 import org.springframework.beans.factory.annotation.Qualifier;
 
 /**
- * Qualifier annotation for a metric repository that is used by the actuator (to
- * distinguish it from others that might be installed by the user).
+ * Qualifier annotation for a metric repository that is to be used to export metrics from
+ * the {@link ExportMetricReader} readers.
  *
  * @author Dave Syer
  */
@@ -37,6 +37,6 @@ import org.springframework.beans.factory.annotation.Qualifier;
 @Retention(RetentionPolicy.RUNTIME)
 @Inherited
 @Documented
-public @interface ActuatorMetricReader {
+public @interface ExportMetricWriter {
 
 }

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfiguration.java

@@ -47,17 +47,14 @@ import org.springframework.scheduling.config.ScheduledTaskRegistrar;
 public class MetricExportAutoConfiguration {
 
 	@Autowired(required = false)
+	@ExportMetricWriter
 	private Map<String, MetricWriter> writers = Collections.emptyMap();
 
 	@Autowired
 	private MetricExportProperties metrics;
 
 	@Autowired(required = false)
-	@ActuatorMetricWriter
-	private List<MetricWriter> actuatorMetrics = Collections.emptyList();
-
-	@Autowired(required = false)
-	@ActuatorMetricReader
+	@ExportMetricReader
 	private List<MetricReader> readers;
 
 	@Autowired(required = false)
@@ -77,11 +74,6 @@ public class MetricExportAutoConfiguration {
 
 		if (reader != null) {
 			writers.putAll(this.writers);
-			for (String name : this.writers.keySet()) {
-				if (this.actuatorMetrics.contains(writers.get(name))) {
-					writers.remove(name);
-				}
-			}
 			MetricExporters exporters = new MetricExporters(reader, writers, this.metrics);
 			return exporters;
 		}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/MetricRepositoryAutoConfiguration.java

@@ -125,7 +125,7 @@ public class MetricRepositoryAutoConfiguration {
 		}
 
 		@Bean
-		@ActuatorMetricReader
+		@ExportMetricReader
 		@ConditionalOnMissingBean
 		public BufferMetricReader actuatorMetricReader(CounterBuffers counters,
 				GaugeBuffers gauges) {
@@ -151,7 +151,7 @@ public class MetricRepositoryAutoConfiguration {
 	static class LegacyMetricRepositoryConfiguration {
 
 		@Bean
-		@ActuatorMetricReader
+		@ExportMetricReader
 		@ActuatorMetricWriter
 		public InMemoryMetricRepository actuatorMetricRepository() {
 			return new InMemoryMetricRepository();

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/PublicMetricsAutoConfiguration.java

@@ -70,7 +70,7 @@ import org.springframework.lang.UsesJava7;
 public class PublicMetricsAutoConfiguration {
 
 	@Autowired(required = false)
-	@ActuatorMetricReader
+	@ExportMetricReader
 	private List<MetricReader> metricReaders = Collections.emptyList();
 
 	@Bean

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/MetricExportProperties.java

@@ -208,8 +208,14 @@ class Trigger {
 	 */
 	private Boolean sendLatest;
 
+	/**
+	 * List of patterns for metric names to include.
+	 */
 	private String[] includes;
 
+	/**
+	 * List of patterns for metric names to exclude. Applied after the includes.
+	 */
 	private String[] excludes;
 
 	public String[] getIncludes() {

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricExportAutoConfigurationTests.java

@@ -116,6 +116,7 @@ public class MetricExportAutoConfigurationTests {
 	public static class WriterConfig {
 
 		@Bean
+		@ExportMetricWriter
 		public MetricWriter writer() {
 			return Mockito.mock(MetricWriter.class);
 		}
@@ -126,6 +127,7 @@ public class MetricExportAutoConfigurationTests {
 	public static class MetricEndpointConfiguration {
 
 		@Bean
+		@ExportMetricReader
 		public MetricsEndpointMetricReader endpointReader() {
 			return Mockito.mock(MetricsEndpointMetricReader.class);
 		}