/**
* Copyright 2008 the original author or authors.
*
* Licensed 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 net.sf.katta.protocol;
import java.util.ArrayList;
import java.util.List;
import net.sf.katta.master.OperationWatchdog;
import net.sf.katta.operation.OperationId;
import net.sf.katta.operation.master.MasterOperation;
import org.I0Itec.zkclient.ZkClient;
import org.I0Itec.zkclient.exception.ZkNoNodeException;
public class MasterQueue extends BlockingQueue<MasterOperation> {
private String _watchdogsPath;
public MasterQueue(ZkClient zkClient, String rootPath) {
super(zkClient, rootPath);
_watchdogsPath = rootPath + "/watchdogs";
_zkClient.createPersistent(_watchdogsPath, true);
// cleanup odd watchdog situations
List<String> watchdogs = _zkClient.getChildren(_watchdogsPath);
for (String elementName : watchdogs) {
try {
_zkClient.delete(getElementPath(elementName));
} catch (ZkNoNodeException e) {
// ignore, can be already deleted by other queue instance
}
}
}
private String getWatchdogPath(String elementId) {
return _watchdogsPath + "/" + elementId;
}
/**
* Moves the top of the queue to the watching state.
*
* @param masterOperation
* @param nodeOperationIds
* @return
* @throws InterruptedException
*/
public OperationWatchdog moveOperationToWatching(MasterOperation masterOperation, List<OperationId> nodeOperationIds)
throws InterruptedException {
Element<MasterOperation> element = getFirstElement();
// we don't use the persisted operation cause the given masterOperation can
// have a changed state
OperationWatchdog watchdog = new OperationWatchdog(element.getName(), masterOperation, nodeOperationIds);
_zkClient.createPersistent(getWatchdogPath(element.getName()), watchdog);
_zkClient.delete(getElementPath(element.getName()));
return watchdog;
}
public List<OperationWatchdog> getWatchdogs() {
List<String> childs = _zkClient.getChildren(_watchdogsPath);
List<OperationWatchdog> watchdogs = new ArrayList<OperationWatchdog>(childs.size());
for (String child : childs) {
watchdogs.add((OperationWatchdog) _zkClient.readData(getWatchdogPath(child)));
}
return watchdogs;
}
public void removeWatchdog(OperationWatchdog watchdog) {
_zkClient.delete(getWatchdogPath(watchdog.getQueueElementId()));
}
}