org.apache.hadoop.metrics.util.MetricsIntValue Maven / Gradle / Ivy
/**
* 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.metrics.util;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.metrics.MetricsRecord;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* The MetricsIntValue class is for a metric that is not time varied
* but changes only when it is set.
* Each time its value is set, it is published only *once* at the next update
* call.
*
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
public class MetricsIntValue extends MetricsBase {
private static final Log LOG =
LogFactory.getLog("org.apache.hadoop.metrics.util");
private int value;
private boolean changed;
/**
* Constructor - create a new metric
* @param nam the name of the metrics to be used to publish the metric
* @param registry - where the metrics object will be registered
*/
public MetricsIntValue(final String nam, final MetricsRegistry registry, final String description) {
super(nam, description);
value = 0;
changed = false;
registry.add(nam, this);
}
/**
* Constructor - create a new metric
* @param nam the name of the metrics to be used to publish the metric
* @param registry - where the metrics object will be registered
* A description of {@link #NO_DESCRIPTION} is used
*/
public MetricsIntValue(final String nam, MetricsRegistry registry) {
this(nam, registry, NO_DESCRIPTION);
}
/**
* Set the value
* @param newValue
*/
public synchronized void set(final int newValue) {
value = newValue;
changed = true;
}
/**
* Get value
* @return the value last set
*/
public synchronized int get() {
return value;
}
/**
* Push the metric to the mr.
* The metric is pushed only if it was updated since last push
*
* Note this does NOT push to JMX
* (JMX gets the info via {@link #get()}
*
* @param mr
*/
public synchronized void pushMetric(final MetricsRecord mr) {
if (changed) {
try {
mr.setMetric(getName(), value);
} catch (Exception e) {
LOG.info("pushMetric failed for " + getName() + "\n", e);
}
}
changed = false;
}
}