From d7499387d8e22d52d8e84cf615416b9a1e9c23a7 Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Mon, 5 Mar 2018 10:54:19 +0000
Subject: [PATCH] Polish "Improve docs on custom metrics"

Closes gh-12324
---
 .../asciidoc/production-ready-features.adoc   | 13 ++----
 .../MetricsMeterRegistryInjectionExample.java | 46 +++++++++++++++++++
 2 files changed, 49 insertions(+), 10 deletions(-)
 create mode 100644 spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuate/metrics/MetricsMeterRegistryInjectionExample.java

diff --git a/spring-boot-project/spring-boot-docs/src/main/asciidoc/production-ready-features.adoc b/spring-boot-project/spring-boot-docs/src/main/asciidoc/production-ready-features.adoc
index 470af18015..72901d1b53 100644
--- a/spring-boot-project/spring-boot-docs/src/main/asciidoc/production-ready-features.adoc
+++ b/spring-boot-project/spring-boot-docs/src/main/asciidoc/production-ready-features.adoc
@@ -1749,19 +1749,12 @@ factories with a metric named `rabbitmq`.
 
 [[production-ready-metrics-custom]]
 === Registering custom metrics
-To register custom metrics, inject `MeterRegistry` into your component:
+To register custom metrics, inject `MeterRegistry` into your component, as shown in the
+following example:
 
 [source,java,indent=0]
 ----
-class Dictionary {
-	private List<String> words = new CopyOnWriteArrayList<>();
-
-	public MyComponent(MeterRegistry registry) {
-		registry.gaugeCollectionSize("dictionary.size", Tags.empty(), words);
-	}
-
-	...
-}
+include::{code-examples}/actuate/metrics/MetricsMeterRegistryInjectionExample.java[tag=component]
 ----
 
 If you find that you repeatedly instrument a suite of metrics across components or
diff --git a/spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuate/metrics/MetricsMeterRegistryInjectionExample.java b/spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuate/metrics/MetricsMeterRegistryInjectionExample.java
new file mode 100644
index 0000000000..3f6975174a
--- /dev/null
+++ b/spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/actuate/metrics/MetricsMeterRegistryInjectionExample.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2018 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.docs.actuate.metrics;
+
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tags;
+
+/**
+ * Example to show injection and use of a {@link MeterRegistry}.
+ *
+ * @author Andy Wilkinson
+ */
+public class MetricsMeterRegistryInjectionExample {
+
+	// tag::component[]
+	class Dictionary {
+
+		private final List<String> words = new CopyOnWriteArrayList<>();
+
+		Dictionary(MeterRegistry registry) {
+			registry.gaugeCollectionSize("dictionary.size", Tags.empty(), this.words);
+		}
+
+		// …
+
+	}
+	// end::component[]
+
+}