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https://codeberg.org/Mercury-IM/Smack
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git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@1894 b35dd754-fafc-0310-a699-88a17e54d16e
216 lines
7.9 KiB
Java
216 lines
7.9 KiB
Java
/**
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* $RCSfile$
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* $Revision$
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* $Date$
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*
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* Copyright (C) 2002-2003 Jive Software. All rights reserved.
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* ====================================================================
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* The Jive Software License (based on Apache Software License, Version 1.1)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. The end-user documentation included with the redistribution,
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* if any, must include the following acknowledgment:
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* "This product includes software developed by
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* Jive Software (http://www.jivesoftware.com)."
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* Alternately, this acknowledgment may appear in the software itself,
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* if and wherever such third-party acknowledgments normally appear.
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*
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* 4. The names "Smack" and "Jive Software" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please
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* contact webmaster@jivesoftware.com.
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*
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* 5. Products derived from this software may not be called "Smack",
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* nor may "Smack" appear in their name, without prior written
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* permission of Jive Software.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL JIVE SOFTWARE OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* ====================================================================
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*/
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package org.jivesoftware.smack;
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import org.jivesoftware.smack.packet.Packet;
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import org.jivesoftware.smack.filter.PacketFilter;
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import java.util.LinkedList;
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/**
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* Provides a mechanism to collect packets into a result queue that pass a
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* specified filter. The collector lets you perform blocking and polling
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* operations on the result queue. So, a PacketCollector is more suitable to
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* use than a {@link PacketListener} when you need to wait for a specific
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* result.<p>
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*
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* Each packet collector will queue up to 2^16 packets for processing before
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* older packets are automatically dropped.
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*
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* @see XMPPConnection#createPacketCollector(PacketFilter)
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* @author Matt Tucker
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*/
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public class PacketCollector {
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/**
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* Max number of packets that any one collector can hold. After the max is
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* reached, older packets will be automatically dropped from the queue as
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* new packets are added.
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*/
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private static final int MAX_PACKETS = 65536;
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private PacketFilter packetFilter;
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private LinkedList resultQueue;
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private PacketReader packetReader;
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private boolean cancelled = false;
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/**
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* Creates a new packet collector. If the packet filter is <tt>null</tt>, then
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* all packets will match this collector.
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*
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* @param packetReader the packetReader the collector is tied to.
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* @param packetFilter determines which packets will be returned by this collector.
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*/
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protected PacketCollector(PacketReader packetReader, PacketFilter packetFilter) {
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this.packetReader = packetReader;
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this.packetFilter = packetFilter;
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this.resultQueue = new LinkedList();
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// Add the collector to the packet reader's list of active collector.
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synchronized (packetReader.collectors) {
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packetReader.collectors.add(this);
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}
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}
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/**
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* Explicitly cancels the packet collector so that no more results are
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* queued up. Once a packet collector has been cancelled, it cannot be
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* re-enabled. Instead, a new packet collector must be created.
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*/
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public void cancel() {
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// If the packet collector has already been cancelled, do nothing.
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if (cancelled) {
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return;
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}
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else {
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cancelled = true;
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// Remove object from collectors list by setting the value in the
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// list at the correct index to null. The collector thread will
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// automatically remove the actual list entry when it can.
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synchronized (packetReader.collectors) {
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int index = packetReader.collectors.indexOf(this);
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packetReader.collectors.set(index, null);
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}
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}
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}
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/**
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* Returns the packet filter associated with this packet collector. The packet
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* filter is used to determine what packets are queued as results.
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*
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* @return the packet filter.
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*/
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public PacketFilter getPacketFilter() {
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return packetFilter;
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}
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/**
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* Polls to see if a packet is currently available and returns it, or
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* immediately returns <tt>null</tt> if no packets are currently in the
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* result queue.
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*
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* @return the next packet result, or <tt>null</tt> if there are no more
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* results.
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*/
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public synchronized Packet pollResult() {
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if (resultQueue.isEmpty()) {
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return null;
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}
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else {
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return (Packet)resultQueue.removeLast();
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}
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}
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/**
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* Returns the next available packet. The method call will block (not return)
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* until a packet is available.
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*
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* @return the next available packet.
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*/
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public synchronized Packet nextResult() {
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// Wait indefinitely until there is a result to return.
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while (resultQueue.isEmpty()) {
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try {
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wait();
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}
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catch (InterruptedException ie) { }
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}
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return (Packet)resultQueue.removeLast();
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}
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/**
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* Returns the next available packet. The method call will block (not return)
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* until a packet is available or the <tt>timeout</tt> has elapased. If the
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* timeout elapses without a result, <tt>null</tt> will be returned.
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*
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* @param timeout the amount of time to wait for the next packet (in milleseconds).
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* @return the next available packet.
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*/
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public synchronized Packet nextResult(long timeout) {
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// Wait up to the specified amount of time for a result.
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if (resultQueue.isEmpty()) {
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try {
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wait(timeout);
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}
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catch (InterruptedException ie) { }
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}
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// If still no result, return null.
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if (resultQueue.isEmpty()) {
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return null;
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}
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else {
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return (Packet)resultQueue.removeLast();
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}
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}
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/**
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* Processes a packet to see if it meets the criteria for this packet collector.
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* If so, the packet is added to the result queue.
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*
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* @param packet the packet to process.
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*/
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protected synchronized void processPacket(Packet packet) {
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if (packet == null) {
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return;
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}
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if (packetFilter == null || packetFilter.accept(packet)) {
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// If the max number of packets has been reached, remove the oldest one.
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if (resultQueue.size() == MAX_PACKETS) {
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resultQueue.removeLast();
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}
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// Add the new packet.
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resultQueue.addFirst(packet);
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// Notify waiting threads a result is available.
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notifyAll();
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}
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}
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}
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