/**
 * 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.activemq.broker.region;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;

import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.thread.TaskRunnerFactory;
import org.apache.activemq.usage.SystemUsage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 */
public abstract class AbstractTempRegion extends AbstractRegion {
    private static final Logger LOG = LoggerFactory.getLogger(TempQueueRegion.class);

    private Map<CachedDestination, Destination> cachedDestinations = new HashMap<CachedDestination, Destination>();
    private final boolean doCacheTempDestinations;
    private final int purgeTime;
    private Timer purgeTimer;
    private TimerTask purgeTask;
   

    /**
     * @param broker
     * @param destinationStatistics
     * @param memoryManager
     * @param taskRunnerFactory
     * @param destinationFactory
     */
    public AbstractTempRegion(RegionBroker broker,
            DestinationStatistics destinationStatistics,
            SystemUsage memoryManager, TaskRunnerFactory taskRunnerFactory,
            DestinationFactory destinationFactory) {
        super(broker, destinationStatistics, memoryManager, taskRunnerFactory,
                destinationFactory);
        this.doCacheTempDestinations=broker.getBrokerService().isCacheTempDestinations();
        this.purgeTime = broker.getBrokerService().getTimeBeforePurgeTempDestinations();
        if (this.doCacheTempDestinations) {
            this.purgeTimer = new Timer("ActiveMQ Temp destination purge timer", true);
            this.purgeTask = new TimerTask() {
                public void run() {
                    doPurge();
                }
    
            };
            this.purgeTimer.schedule(purgeTask, purgeTime, purgeTime);
        }
       
    }

    public void stop() throws Exception {
        super.stop();
        if (purgeTimer != null) {
            purgeTimer.cancel();
        }
    }

    protected synchronized Destination createDestination(
            ConnectionContext context, ActiveMQDestination destination)
            throws Exception {
        Destination result = cachedDestinations.remove(new CachedDestination(
                destination));
        if (result == null) {
            result =  destinationFactory.createDestination(context, destination, destinationStatistics);
        }
        return result;
    }

    protected final synchronized void dispose(ConnectionContext context,
            Destination dest) throws Exception {
        // add to cache
        if (this.doCacheTempDestinations) {
            cachedDestinations.put(new CachedDestination(dest
                    .getActiveMQDestination()), dest);
        }else {
            try {
                dest.dispose(context);
                dest.stop();
            } catch (Exception e) {
                LOG.warn("Failed to dispose of {}", dest, e);
            }
        }
    }

    private void doDispose(Destination dest) {
        ConnectionContext context = new ConnectionContext();
        try {
            dest.dispose(context);
            dest.stop();
        } catch (Exception e) {
            LOG.warn("Failed to dispose of {}", dest, e);
        }

    }

    private synchronized void doPurge() {
        long currentTime = System.currentTimeMillis();
        if (cachedDestinations.size() > 0) {
            Set<CachedDestination> tmp = new HashSet<CachedDestination>(
                    cachedDestinations.keySet());
            for (CachedDestination key : tmp) {
                if ((key.timeStamp + purgeTime) < currentTime) {
                    Destination dest = cachedDestinations.remove(key);
                    if (dest != null) {
                        doDispose(dest);
                    }
                }
            }
        }
    }

    static class CachedDestination {
        long timeStamp;

        ActiveMQDestination destination;

        CachedDestination(ActiveMQDestination destination) {
            this.destination = destination;
            this.timeStamp = System.currentTimeMillis();
        }

        public int hashCode() {
            return destination.hashCode();
        }

        public boolean equals(Object o) {
            if (o instanceof CachedDestination) {
                CachedDestination other = (CachedDestination) o;
                return other.destination.equals(this.destination);
            }
            return false;
        }

    }

}