From 5e3b5ae14fed1cef6bc00a6bf62c8feffc2e1ffd Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Thu, 11 Oct 2018 17:25:54 +0100
Subject: [PATCH] Polish

See gh-14780 and gh-14467
---
 .../metrics/MeterRegistryPostProcessor.java   | 23 +++++++++++--------
 .../metrics/MetricsAutoConfiguration.java     |  8 +++----
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java b/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java
index 6a2985b672..1c96c9c298 100644
--- a/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java
+++ b/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java
@@ -16,8 +16,8 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
-import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.binder.MeterBinder;
@@ -37,19 +37,19 @@ import org.springframework.beans.factory.config.BeanPostProcessor;
  */
 class MeterRegistryPostProcessor implements BeanPostProcessor {
 
-	private final ObjectProvider<List<MeterBinder>> meterBinders;
+	private final ObjectProvider<MeterBinder> meterBinders;
 
-	private final ObjectProvider<List<MeterFilter>> meterFilters;
+	private final ObjectProvider<MeterFilter> meterFilters;
 
-	private final ObjectProvider<List<MeterRegistryCustomizer<?>>> meterRegistryCustomizers;
+	private final ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers;
 
 	private final ObjectProvider<MetricsProperties> metricsProperties;
 
 	private volatile MeterRegistryConfigurer configurer;
 
-	MeterRegistryPostProcessor(ObjectProvider<List<MeterBinder>> meterBinders,
-			ObjectProvider<List<MeterFilter>> meterFilters,
-			ObjectProvider<List<MeterRegistryCustomizer<?>>> meterRegistryCustomizers,
+	MeterRegistryPostProcessor(ObjectProvider<MeterBinder> meterBinders,
+			ObjectProvider<MeterFilter> meterFilters,
+			ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
 			ObjectProvider<MetricsProperties> metricsProperties) {
 		this.meterBinders = meterBinders;
 		this.meterFilters = meterFilters;
@@ -69,12 +69,15 @@ class MeterRegistryPostProcessor implements BeanPostProcessor {
 	private MeterRegistryConfigurer getConfigurer() {
 		if (this.configurer == null) {
 			this.configurer = new MeterRegistryConfigurer(
-					this.meterBinders.getIfAvailable(Collections::emptyList),
-					this.meterFilters.getIfAvailable(Collections::emptyList),
-					this.meterRegistryCustomizers.getIfAvailable(Collections::emptyList),
+					asOrderedList(this.meterBinders), asOrderedList(this.meterFilters),
+					asOrderedList(this.meterRegistryCustomizers),
 					this.metricsProperties.getObject().isUseGlobalRegistry());
 		}
 		return this.configurer;
 	}
 
+	private <T> List<T> asOrderedList(ObjectProvider<T> provider) {
+		return provider.orderedStream().collect(Collectors.toList());
+	}
+
 }
diff --git a/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java b/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java
index 4d2d0d243c..7a2d49c816 100644
--- a/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java
+++ b/spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java
@@ -16,8 +16,6 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
-import java.util.List;
-
 import io.micrometer.core.annotation.Timed;
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.binder.MeterBinder;
@@ -54,9 +52,9 @@ public class MetricsAutoConfiguration {
 
 	@Bean
 	public static MeterRegistryPostProcessor meterRegistryPostProcessor(
-			ObjectProvider<List<MeterBinder>> meterBinders,
-			ObjectProvider<List<MeterFilter>> meterFilters,
-			ObjectProvider<List<MeterRegistryCustomizer<?>>> meterRegistryCustomizers,
+			ObjectProvider<MeterBinder> meterBinders,
+			ObjectProvider<MeterFilter> meterFilters,
+			ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
 			ObjectProvider<MetricsProperties> metricsProperties) {
 		return new MeterRegistryPostProcessor(meterBinders, meterFilters,
 				meterRegistryCustomizers, metricsProperties);