org.apache.hadoop.metrics.util.MetricsRegistry 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 java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.hadoop.classification.InterfaceAudience;
/**
*
* This is the registry for metrics.
* Related set of metrics should be declared in a holding class and registered
* in a registry for those metrics which is also stored in the the holding class.
*
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
public class MetricsRegistry {
private ConcurrentHashMap metricsList =
new ConcurrentHashMap();
public MetricsRegistry() {
}
/**
*
* @return number of metrics in the registry
*/
public int size() {
return metricsList.size();
}
/**
* Add a new metrics to the registry
* @param metricsName - the name
* @param theMetricsObj - the metrics
* @throws IllegalArgumentException if a name is already registered
*/
public void add(final String metricsName, final MetricsBase theMetricsObj) {
if (metricsList.putIfAbsent(metricsName, theMetricsObj) != null) {
throw new IllegalArgumentException("Duplicate metricsName:" +
metricsName);
}
}
/**
*
* @param metricsName
* @return the metrics if there is one registered by the supplied name.
* Returns null if none is registered
*/
public MetricsBase get(final String metricsName) {
return metricsList.get(metricsName);
}
/**
*
* @return the list of metrics names
*/
public Collection getKeyList() {
return metricsList.keySet();
}
/**
*
* @return the list of metrics
*/
public Collection getMetricsList() {
return metricsList.values();
}
}