/**
 *  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.geronimo.connector.outbound;

import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.ArrayList;

import javax.resource.ResourceException;
import javax.resource.spi.ManagedConnection;
import javax.resource.spi.ManagedConnectionFactory;

/**
 * This pool is the most spec-compliant pool.  It can be used by itself with no partitioning.
 * It is apt to be the slowest pool.
 * For each connection request, it synchronizes access to the pool and asks the
 * ManagedConnectionFactory for a match from among all managed connections.  If none is found,
 * it may discard a random existing connection, and creates a new connection.
 *
 * @version $Rev$ $Date$
 */
public class SinglePoolMatchAllConnectionInterceptor extends AbstractSinglePoolConnectionInterceptor {

    private final Map<ManagedConnection, ManagedConnectionInfo> pool;

    public SinglePoolMatchAllConnectionInterceptor(final ConnectionInterceptor next,
                                                   int maxSize,
                                                   int minSize,
                                                   int blockingTimeoutMilliseconds,
                                                   int idleTimeoutMinutes) {

        super(next, maxSize, minSize, blockingTimeoutMilliseconds, idleTimeoutMinutes);
        pool = new IdentityHashMap<ManagedConnection, ManagedConnectionInfo>(maxSize);
    }

    protected void internalGetConnection(ConnectionInfo connectionInfo) throws ResourceException {
        synchronized (pool) {
            if (destroyed) {
                throw new ResourceException("ManagedConnection pool has been destroyed");
            }
            if (!pool.isEmpty()) {
                ManagedConnectionInfo mci = connectionInfo.getManagedConnectionInfo();
                ManagedConnectionFactory managedConnectionFactory = mci.getManagedConnectionFactory();
                ManagedConnection matchedMC =
                        managedConnectionFactory
                                .matchManagedConnections(pool.keySet(),
                                        mci.getSubject(),
                                        mci.getConnectionRequestInfo());
                if (matchedMC != null) {
                    connectionInfo.setManagedConnectionInfo(pool.get(matchedMC));
                    pool.remove(matchedMC);
                    if (log.isTraceEnabled()) {
                        log.trace("Returning pooled connection " + connectionInfo.getManagedConnectionInfo());
                    }
                    if (connectionCount < minSize) {
                        timer.schedule(new FillTask(connectionInfo), 10);
                    }
                    return;
                }
            }
            //matching failed or pool is empty
            //if pool is at maximum size, pick a cx to kill
            if (connectionCount == maxSize) {
                Iterator iterator = pool.entrySet().iterator();
                ManagedConnectionInfo kill = (ManagedConnectionInfo) ((Map.Entry) iterator.next()).getValue();
                iterator.remove();
                ConnectionInfo killInfo = new ConnectionInfo(kill);
                internalReturn(killInfo, ConnectionReturnAction.DESTROY);
            }
            next.getConnection(connectionInfo);
            connectionCount++;
            if (log.isTraceEnabled()) {
                log.trace("Returning new connection " + connectionInfo.getManagedConnectionInfo());
            }
            if (connectionCount < minSize) {
                timer.schedule(new FillTask(connectionInfo), 10);
            }

        }
    }

    protected void doAdd(ManagedConnectionInfo mci) {
        pool.put(mci.getManagedConnection(), mci);
    }

    protected Object getPool() {
        return pool;
    }

    protected boolean doRemove(ManagedConnectionInfo mci) {
        return pool.remove(mci.getManagedConnection()) == null;
    }

    protected void internalDestroy() {
        synchronized (pool) {
            for (ManagedConnection managedConnection : pool.keySet()) {
                try {
                    managedConnection.destroy();
                } catch (ResourceException ignore) {
                }
            }
            pool.clear();
        }
    }

    public int getIdleConnectionCount() {
        synchronized (pool) {
            return pool.size();
        }
    }

    protected void transferConnections(int maxSize, int shrinkNow) {
        List<ConnectionInfo> killList = new ArrayList<ConnectionInfo>(shrinkNow);
        Iterator<Map.Entry<ManagedConnection, ManagedConnectionInfo>> it = pool.entrySet().iterator();
        for (int i = 0; i < shrinkNow; i++) {
            killList.add(new ConnectionInfo(it.next().getValue()));
        }
        for (ConnectionInfo killInfo: killList) {
            internalReturn(killInfo, ConnectionReturnAction.DESTROY);
        }
    }

    protected void getExpiredManagedConnectionInfos(long threshold, List<ManagedConnectionInfo> killList) {
        synchronized (pool) {
            for (ManagedConnectionInfo mci : pool.values()) {
                if (mci.getLastUsed() < threshold) {
                    killList.add(mci);
                }
            }
        }

    }

}