From 1c3776b5e700b6182f900bb2c49458d4890d665f Mon Sep 17 00:00:00 2001
From: Jorge Esteban Quilcate Otoya <quilcate.jorge@gmail.com>
Date: Sun, 8 Mar 2020 22:28:10 +0100
Subject: [PATCH] refactor: simplify currentMeters ref

---
 .../instrument/binder/kafka/KafkaMetrics.java |  5 ++---
 .../binder/kafka/KafkaMetricsTest.java        | 21 ++++++++++++-------
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/binder/kafka/KafkaMetrics.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/binder/kafka/KafkaMetrics.java
index 12de7ef684..853b42a81d 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/binder/kafka/KafkaMetrics.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/binder/kafka/KafkaMetrics.java
@@ -113,7 +113,7 @@ void checkAndBindMetrics(MeterRegistry registry) {
             synchronized (this) { //Enforce only happens once when metrics change
                 if (!currentMeters.equals(metrics.keySet())) {
                     //Register meters
-                    currentMeters = new HashSet<>();
+                    currentMeters = new HashSet<>(metrics.keySet());
                     metrics.forEach((name, metric) -> {
                         //Filter out metrics from group "app-info", that includes metadata
                         if (METRIC_GROUP_APP_INFO.equals(name.group())) return;
@@ -124,7 +124,7 @@ void checkAndBindMetrics(MeterRegistry registry) {
                         for (Meter meter : meters) {
                             if (meter.getId().getTags().size() < (metricTags(metric).size() + extraTagsSize))
                                 registry.remove(meter);
-                            // if already exists
+                            // Check if already exists
                             else if (meter.getId().getTags().equals(metricTags(metric))) return;
                             else hasLessTags = true;
                         }
@@ -132,7 +132,6 @@ void checkAndBindMetrics(MeterRegistry registry) {
                         //Filter out non-numeric values
                         if (!isNumber(metric)) return;
                         bindMeter(registry, metric);
-                        currentMeters.add(name);
                     });
                 }
             }
diff --git a/micrometer-core/src/test/java/io/micrometer/core/instrument/binder/kafka/KafkaMetricsTest.java b/micrometer-core/src/test/java/io/micrometer/core/instrument/binder/kafka/KafkaMetricsTest.java
index 3ca6e3a600..678e5a9ea1 100644
--- a/micrometer-core/src/test/java/io/micrometer/core/instrument/binder/kafka/KafkaMetricsTest.java
+++ b/micrometer-core/src/test/java/io/micrometer/core/instrument/binder/kafka/KafkaMetricsTest.java
@@ -21,6 +21,7 @@
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
 import org.apache.kafka.common.Metric;
 import org.apache.kafka.common.MetricName;
@@ -57,13 +58,14 @@ class KafkaMetricsTest {
 
     @Test void shouldAddNewMetersWhenMetricsChange() {
         //Given
-        Map<MetricName, KafkaMetric> metrics = new LinkedHashMap<>();
-        Supplier<Map<MetricName, ? extends Metric>> supplier = () -> {
+        AtomicReference<Map<MetricName, KafkaMetric>> metrics = new AtomicReference<>();
+        metrics.set(new LinkedHashMap<>());
+        Supplier<Map<MetricName, ? extends Metric>> supplier = () -> metrics.updateAndGet(map -> {
             MetricName metricName = new MetricName("a0", "b0", "c0", new LinkedHashMap<>());
             KafkaMetric metric = new KafkaMetric(this, metricName, new Value(), new MetricConfig(), Time.SYSTEM);
-            metrics.put(metricName, metric);
-            return metrics;
-        };
+            map.put(metricName, metric);
+            return map;
+        });
         KafkaMetrics kafkaMetrics = new KafkaMetrics(supplier);
         MeterRegistry registry = new SimpleMeterRegistry();
         //When
@@ -71,9 +73,12 @@ class KafkaMetricsTest {
         //Then
         assertThat(registry.getMeters()).hasSize(1);
         //Given
-        MetricName metricName = new MetricName("a1", "b1", "c1", new LinkedHashMap<>());
-        KafkaMetric metric = new KafkaMetric(this, metricName, new Value(), new MetricConfig(), Time.SYSTEM);
-        metrics.put(metricName, metric);
+        metrics.updateAndGet(map -> {
+            MetricName metricName = new MetricName("a1", "b1", "c1", new LinkedHashMap<>());
+            KafkaMetric metric = new KafkaMetric(this, metricName, new Value(), new MetricConfig(), Time.SYSTEM);
+            map.put(metricName, metric);
+            return map;
+        });
         //When
         kafkaMetrics.checkAndBindMetrics(registry);
         //Then