/**
 * Copyright 2007-2016, Kaazing Corporation. All rights reserved.
 *
 * 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 org.apache.mina.core.session;

import java.net.SocketAddress;
import java.util.ArrayList;
import java.util.List;

import org.apache.mina.util.ExpirationListener;
import org.apache.mina.util.ExpiringMap;

/**
 * An {@link IoSessionRecycler} with sessions that time out on inactivity.
 *
 * TODO Document me.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 * @org.apache.xbean.XBean
 */
public class ExpiringSessionRecycler implements IoSessionRecycler {
    private ExpiringMap<Object, IoSession> sessionMap;

    private ExpiringMap<Object, IoSession>.Expirer mapExpirer;

    public ExpiringSessionRecycler() {
        this(ExpiringMap.DEFAULT_TIME_TO_LIVE);
    }

    public ExpiringSessionRecycler(int timeToLive) {
        this(timeToLive, ExpiringMap.DEFAULT_EXPIRATION_INTERVAL);
    }

    public ExpiringSessionRecycler(int timeToLive, int expirationInterval) {
        sessionMap = new ExpiringMap<>(timeToLive,
                expirationInterval);
        mapExpirer = sessionMap.getExpirer();
        sessionMap.addExpirationListener(new DefaultExpirationListener());
    }

    public void put(IoSession session) {
        mapExpirer.startExpiringIfNotStarted();

        Object key = generateKey(session);

        if (!sessionMap.containsKey(key)) {
            sessionMap.put(key, session);
        }
    }

    public IoSession recycle(SocketAddress localAddress,
            SocketAddress remoteAddress) {
        return sessionMap.get(generateKey(localAddress, remoteAddress));
    }

    public void remove(IoSession session) {
        sessionMap.remove(generateKey(session));
    }

    public void stopExpiring() {
        mapExpirer.stopExpiring();
    }

    public int getExpirationInterval() {
        return sessionMap.getExpirationInterval();
    }

    public int getTimeToLive() {
        return sessionMap.getTimeToLive();
    }

    public void setExpirationInterval(int expirationInterval) {
        sessionMap.setExpirationInterval(expirationInterval);
    }

    public void setTimeToLive(int timeToLive) {
        sessionMap.setTimeToLive(timeToLive);
    }

    private Object generateKey(IoSession session) {
        return generateKey(session.getLocalAddress(), session
                .getRemoteAddress());
    }

    private Object generateKey(SocketAddress localAddress,
            SocketAddress remoteAddress) {
        List<SocketAddress> key = new ArrayList<>(2);
        key.add(remoteAddress);
        key.add(localAddress);
        return key;
    }

    private class DefaultExpirationListener implements
            ExpirationListener<IoSession> {
        public void expired(IoSession expiredSession) {
            expiredSession.close(true);
        }
    }
}
