org.apache.hadoop.metrics2.lib.MutableMetric Maven / Gradle / Ivy
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* 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; }
}