| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.hadoop.metrics2.lib; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.metrics2.MetricsRecordBuilder; |
| |
| /** |
| * The mutable metric interface |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| public abstract class MutableMetric { |
| private volatile boolean changed = true; |
| |
| /** |
| * Get a snapshot of the metric |
| * @param builder the metrics record builder |
| * @param all if true, snapshot unchanged metrics as well |
| */ |
| public abstract void snapshot(MetricsRecordBuilder builder, boolean all); |
| |
| /** |
| * Get a snapshot of metric if changed |
| * @param builder the metrics record builder |
| */ |
| public void snapshot(MetricsRecordBuilder builder) { |
| snapshot(builder, false); |
| } |
| |
| /** |
| * Set the changed flag in mutable operations |
| */ |
| protected void setChanged() { changed = true; } |
| |
| /** |
| * Clear the changed flag in the snapshot operations |
| */ |
| protected void clearChanged() { changed = false; } |
| |
| /** |
| * @return true if metric is changed since last snapshot/snapshot |
| */ |
| public boolean changed() { return changed; } |
| } |