org.apache.hadoop.service.LoggingStateChangeListener 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.service;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This is a state change listener that logs events at INFO level
*/
@Public
@Evolving
public class LoggingStateChangeListener implements ServiceStateChangeListener {
private static final Logger LOG =
LoggerFactory.getLogger(LoggingStateChangeListener.class);
private final Logger log;
/**
* Log events to the given log
* @param log destination for events
*/
public LoggingStateChangeListener(Logger log) {
//force an NPE if a null log came in
log.isDebugEnabled();
this.log = log;
}
/**
* Log events to the static log for this class
*/
public LoggingStateChangeListener() {
this(LOG);
}
/**
* Callback for a state change event: log it
* @param service the service that has changed.
*/
@Override
public void stateChanged(Service service) {
log.info("Entry to state " + service.getServiceState()
+ " for " + service.getName());
}
}