Add Compilation JVM metric binder

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jvm/CompilationMetrics.java

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+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 io.micrometer.core.instrument.binder.jvm;
+
+import io.micrometer.core.instrument.FunctionCounter;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.Tags;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import io.micrometer.core.lang.NonNullApi;
+import io.micrometer.core.lang.NonNullFields;
+
+import java.lang.management.CompilationMXBean;
+import java.lang.management.ManagementFactory;
+
+import static java.util.Collections.emptyList;
+
+@NonNullApi
+@NonNullFields
+public class CompilationMetrics implements MeterBinder {
+    private final Iterable<Tag> tags;
+
+    public CompilationMetrics() {
+        this(emptyList());
+    }
+
+    public CompilationMetrics(Iterable<Tag> tags) {
+        this.tags = tags;
+    }
+
+    @Override
+    public void bindTo(MeterRegistry registry) {
+        CompilationMXBean compilationBean = ManagementFactory.getCompilationMXBean();
+        if (compilationBean.isCompilationTimeMonitoringSupported()) {
+            FunctionCounter.builder("jvm.compilation.time.total", compilationBean, CompilationMXBean::getTotalCompilationTime)
+                    .tags(Tags.concat(tags, "compiler", compilationBean.getName()))
+                    .description("The approximate accumulated elapsed time spent in compilation")
+                    .baseUnit("ms")
+                    .register(registry);
+        }
+    }
+}

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/jvm/CompilationMetricsTest.java

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+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 io.micrometer.core.instrument.binder.jvm;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+class CompilationMetricsTest {
+    @Test
+    void compilationTimeMetric() {
+        MeterRegistry registry = new SimpleMeterRegistry();
+        new CompilationMetrics().bindTo(registry);
+
+        assertThat(registry.get("jvm.compilation.time.total").functionCounter().count()).isGreaterThan(0);
+    }
+}