| /** |
| * 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.ambari.server.agent; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.NoSuchElementException; |
| import java.util.Queue; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.inject.Singleton; |
| |
| @Singleton |
| public class ActionQueue { |
| |
| private static Logger LOG = LoggerFactory.getLogger(ActionQueue.class); |
| |
| Map<String, Queue<AgentCommand>> hostQueues; |
| |
| public ActionQueue() { |
| hostQueues = new HashMap<String, Queue<AgentCommand>>(); |
| } |
| |
| private synchronized Queue<AgentCommand> getQueue(String hostname) { |
| return hostQueues.get(hostname); |
| } |
| |
| private synchronized void addQueue(String hostname, Queue<AgentCommand> q) { |
| hostQueues.put(hostname, q); |
| } |
| |
| public void enqueue(String hostname, AgentCommand cmd) { |
| Queue<AgentCommand> q; |
| synchronized (this) { |
| q = getQueue(hostname); |
| if (q == null) { |
| addQueue(hostname, new LinkedList<AgentCommand>()); |
| q = getQueue(hostname); |
| } |
| } |
| synchronized (q) { |
| if (q.contains(cmd)) { |
| LOG.warn("cmd already exists in the queue, not adding again"); |
| return; |
| } |
| q.add(cmd); |
| } |
| } |
| |
| public AgentCommand dequeue(String hostname) { |
| Queue<AgentCommand> q = getQueue(hostname); |
| if (q == null) { |
| return null; |
| } |
| synchronized (q) { |
| if (q.isEmpty()) { |
| return null; |
| } else { |
| return q.remove(); |
| } |
| } |
| } |
| |
| public AgentCommand dequeue(String hostname, String commandId) { |
| Queue<AgentCommand> q = getQueue(hostname); |
| if (q == null) { |
| return null; |
| } |
| synchronized (q) { |
| if (q.isEmpty()) { |
| return null; |
| } else { |
| AgentCommand c = null; |
| for (Iterator it = q.iterator(); it.hasNext();) { |
| AgentCommand ac = (AgentCommand) it.next(); |
| if (ac instanceof ExecutionCommand && ((ExecutionCommand) ac) |
| .getCommandId().equals(commandId)) { |
| c = ac; |
| it.remove(); |
| break; |
| } |
| } |
| return c; |
| } |
| } |
| } |
| |
| public int size(String hostname) { |
| Queue<AgentCommand> q = getQueue(hostname); |
| if (q == null) { |
| return 0; |
| } |
| synchronized(q) { |
| return q.size(); |
| } |
| } |
| |
| public List<AgentCommand> dequeueAll(String hostname) { |
| Queue<AgentCommand> q = getQueue(hostname); |
| if (q == null) { |
| return null; |
| } |
| List<AgentCommand> l = new ArrayList<AgentCommand>(); |
| synchronized (q) { |
| while (true) { |
| try { |
| AgentCommand cmd = q.remove(); |
| if (cmd != null) { |
| l.add(cmd); |
| } |
| } catch (NoSuchElementException ex) { |
| return l; |
| } |
| } |
| } |
| } |
| } |