/*

 * Copyright 2005-2008 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.net.www.http;

import java.util.concurrent.LinkedBlockingQueue;

import java.util.concurrent.TimeUnit;

import java.io.IOException;

import sun.net.NetProperties;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * This class is used to cleanup any remaining data that may be on a KeepAliveStream

 * so that the connection can be cached in the KeepAliveCache.

 * Instances of this class can be used as a FIFO queue for KeepAliveCleanerEntry objects.

 * Executing this Runnable removes each KeepAliveCleanerEntry from the Queue, reads

 * the reamining bytes on its KeepAliveStream, and if successful puts the connection in

 * the KeepAliveCache.

 *

 * @author Chris Hegarty

 */

@SuppressWarnings("serial")  // never serialized

public class KeepAliveStreamCleaner extends LinkedBlockingQueue<KeepAliveCleanerEntry> implements Runnable

{

    // maximum amount of remaining data that we will try to cleanup

    protected static int MAX_DATA_REMAINING = 512;

    // maximum amount of KeepAliveStreams to be queued

    protected static int MAX_CAPACITY = 10;

    // timeout for both socket and poll on the queue

    protected static final int TIMEOUT = 5000;

    // max retries for skipping data

    private static final int MAX_RETRIES = 5;

    static {

        final String maxDataKey = "http.KeepAlive.remainingData";

        int maxData = AccessController.doPrivileged(

            new PrivilegedAction<Integer>() {

                public Integer run() {

                    return NetProperties.getInteger(maxDataKey, MAX_DATA_REMAINING);

                }}).intValue() * 1024;

        MAX_DATA_REMAINING = maxData;

        final String maxCapacityKey = "http.KeepAlive.queuedConnections";

        int maxCapacity = AccessController.doPrivileged(

            new PrivilegedAction<Integer>() {

                public Integer run() {

                    return NetProperties.getInteger(maxCapacityKey, MAX_CAPACITY);

                }}).intValue();

        MAX_CAPACITY = maxCapacity;

    }

    public KeepAliveStreamCleaner()

    {

        super(MAX_CAPACITY);

    }

    public KeepAliveStreamCleaner(int capacity)

    {

        super(capacity);

    }

    public void run()

    {

        KeepAliveCleanerEntry kace = null;

        do {

            try {

                kace = poll((long)TIMEOUT, TimeUnit.MILLISECONDS);

                if(kace == null)

                    break;

                KeepAliveStream kas = kace.getKeepAliveStream();

                if (kas != null) {

                    synchronized(kas) {

                        HttpClient hc = kace.getHttpClient();

                        try {

                            if (hc != null && !hc.isInKeepAliveCache()) {

                                long remainingToRead = kas.remainingToRead();

                                if (remainingToRead > 0) {

                                    long n = 0;

                                    int retries = 0;

                                    while (n < remainingToRead && retries < MAX_RETRIES) {

                                        remainingToRead = remainingToRead - n;

                                        n = kas.skip(remainingToRead);

                                        if (n == 0)

                                            retries++;

                                    }

                                    remainingToRead = remainingToRead - n;

                                }

                                if (remainingToRead == 0) {

                                    hc.finished();

                                } else

                                    hc.closeServer();

                            }

                        } catch (IOException ioe) {

                            hc.closeServer();

                        } finally {

                            kas.setClosed();

                        }

                    }

                }

            } catch (InterruptedException ie) { }

        } while (kace != null);

    }

}