1 files changed, 43 insertions, 0 deletions
diff --git a/java/com/google/gerrit/metrics/CallbackMetric0.java b/java/com/google/gerrit/metrics/CallbackMetric0.java
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+++ b/java/com/google/gerrit/metrics/CallbackMetric0.java
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+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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 com.google.gerrit.metrics;
+
+/**
+ * Metric whose value is supplied when the trigger is invoked.
+ *
+ * <pre>
+ *   CallbackMetric0&lt;Long&gt; hits = metricMaker.newCallbackMetric("hits", ...);
+ *   CallbackMetric0&lt;Long&gt; total = metricMaker.newCallbackMetric("total", ...);
+ *   metricMaker.newTrigger(hits, total, new Runnable() {
+ *     public void run() {
+ *       hits.set(1);
+ *       total.set(5);
+ *     }
+ *   });
+ * </pre>
+ *
+ * @param <V> type of the metric value, typically Integer or Long.
+ */
+public abstract class CallbackMetric0<V> implements CallbackMetric<V> {
+  /**
+   * Supply the current value of the metric.
+   *
+   * @param value current value.
+   */
+  public abstract void set(V value);
+
+  @Override
+  public void prune() {}
+}