519 lines
18 KiB
Java
519 lines
18 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 2003-2004 Jive Software.
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*
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* All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jivesoftware.smack;
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import org.jivesoftware.smack.filter.PacketFilter;
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import org.jivesoftware.smack.packet.Packet;
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import java.io.IOException;
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import java.io.Writer;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Queue;
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import java.util.concurrent.ConcurrentLinkedQueue;
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/**
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* Writes packets to a XMPP server. Packets are sent using a dedicated thread. Packet
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* interceptors can be registered to dynamically modify packets before they're actually
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* sent. Packet listeners can be registered to listen for all outgoing packets.
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*
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* @author Matt Tucker
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*/
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class PacketWriter {
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private Thread writerThread;
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private Thread keepAliveThread;
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private Writer writer;
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private XMPPConnection connection;
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final private Queue<Packet> queue;
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private boolean done;
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final protected List<ListenerWrapper> listeners = new ArrayList<ListenerWrapper>();
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private boolean listenersDeleted;
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/**
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* Timestamp when the last stanza was sent to the server. This information is used
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* by the keep alive process to only send heartbeats when the connection has been idle.
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*/
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private long lastActive = System.currentTimeMillis();
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/**
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* List of PacketInterceptor that will be notified when a new packet is about to be
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* sent to the server. These interceptors may modify the packet before it is being
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* actually sent to the server.
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*/
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final private List interceptors = new ArrayList();
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/**
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* Flag that indicates if an interceptor was deleted. This is an optimization flag.
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*/
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private boolean interceptorDeleted = false;
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/**
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* Creates a new packet writer with the specified connection.
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*
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* @param connection the connection.
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*/
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protected PacketWriter(XMPPConnection connection) {
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this.queue = new ConcurrentLinkedQueue<Packet>();
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this.connection = connection;
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init();
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}
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/**
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* Initializes the writer in order to be used. It is called at the first connection and also
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* is invoked if the connection is disconnected by an error.
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*/
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protected void init() {
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this.writer = connection.writer;
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listenersDeleted = false;
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interceptorDeleted = false;
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done = false;
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writerThread = new Thread() {
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public void run() {
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writePackets(this);
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}
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};
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writerThread.setName("Smack Packet Writer");
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writerThread.setDaemon(true);
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}
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/**
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* Sends the specified packet to the server.
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*
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* @param packet the packet to send.
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*/
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public void sendPacket(Packet packet) {
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if (!done) {
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// Invoke interceptors for the new packet that is about to be sent. Interceptors
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// may modify the content of the packet.
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processInterceptors(packet);
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queue.add(packet);
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synchronized (queue) {
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queue.notifyAll();
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}
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// Process packet writer listeners. Note that we're using the sending
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// thread so it's expected that listeners are fast.
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processListeners(packet);
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}
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}
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/**
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* Registers a packet listener with this writer. The listener will be
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* notified immediately after every packet this writer sends. A packet filter
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* determines which packets will be delivered to the listener. Note that the thread
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* that writes packets will be used to invoke the listeners. Therefore, each
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* packet listener should complete all operations quickly or use a different
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* thread for processing.
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*
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* @param packetListener the packet listener to notify of sent packets.
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* @param packetFilter the packet filter to use.
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*/
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public void addPacketListener(PacketListener packetListener, PacketFilter packetFilter) {
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synchronized (listeners) {
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listeners.add(new ListenerWrapper(packetListener, packetFilter));
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}
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}
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/**
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* Removes a packet listener.
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*
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* @param packetListener the packet listener to remove.
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*/
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public void removePacketListener(PacketListener packetListener) {
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synchronized (listeners) {
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for (int i=0; i<listeners.size(); i++) {
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ListenerWrapper wrapper = listeners.get(i);
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if (wrapper != null && wrapper.packetListener.equals(packetListener)) {
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listeners.set(i, null);
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// Set the flag to indicate that the listener list needs
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// to be cleaned up.
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listenersDeleted = true;
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}
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}
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}
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}
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/**
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* Returns the number of registered packet listeners.
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*
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* @return the count of packet listeners.
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*/
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public int getPacketListenerCount() {
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synchronized (listeners) {
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return listeners.size();
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}
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}
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/**
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* Registers a packet interceptor with this writer. The interceptor will be
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* notified of every packet that this writer is about to send. Interceptors
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* may modify the packet to be sent. A packet filter determines which packets
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* will be delivered to the interceptor.
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*
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* @param packetInterceptor the packet interceptor to notify of packets about to be sent.
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* @param packetFilter the packet filter to use.
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*/
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public void addPacketInterceptor(PacketInterceptor packetInterceptor, PacketFilter packetFilter) {
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synchronized (interceptors) {
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interceptors.add(new InterceptorWrapper(packetInterceptor, packetFilter));
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}
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}
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/**
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* Removes a packet interceptor.
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*
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* @param packetInterceptor the packet interceptor to remove.
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*/
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public void removePacketInterceptor(PacketInterceptor packetInterceptor) {
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synchronized (interceptors) {
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for (int i=0; i<interceptors.size(); i++) {
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InterceptorWrapper wrapper = (InterceptorWrapper)interceptors.get(i);
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if (wrapper != null && wrapper.packetInterceptor.equals(packetInterceptor)) {
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interceptors.set(i, null);
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// Set the flag to indicate that the interceptor list needs
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// to be cleaned up.
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interceptorDeleted = true;
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}
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}
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}
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}
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/**
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* Starts the packet writer thread and opens a connection to the server. The
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* packet writer will continue writing packets until {@link #shutdown} or an
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* error occurs.
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*/
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public void startup() {
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writerThread.start();
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}
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/**
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* Starts the keep alive process. A white space (aka heartbeat) is going to be
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* sent to the server every 30 seconds (by default) since the last stanza was sent
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* to the server.
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*/
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void startKeepAliveProcess() {
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// Schedule a keep-alive task to run if the feature is enabled. will write
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// out a space character each time it runs to keep the TCP/IP connection open.
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int keepAliveInterval = SmackConfiguration.getKeepAliveInterval();
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if (keepAliveInterval > 0) {
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KeepAliveTask target = new KeepAliveTask(keepAliveInterval);
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keepAliveThread = new Thread(target);
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target.setThread(keepAliveThread);
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keepAliveThread.setDaemon(true);
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keepAliveThread.setName("Smack Keep Alive");
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keepAliveThread.start();
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}
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}
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void setWriter(Writer writer) {
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this.writer = writer;
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}
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/**
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* Shuts down the packet writer. Once this method has been called, no further
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* packets will be written to the server.
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*/
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public void shutdown() {
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done = true;
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synchronized (queue) {
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queue.notifyAll();
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}
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}
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/**
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* Returns the next available packet from the queue for writing.
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*
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* @return the next packet for writing.
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*/
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private Packet nextPacket() {
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Packet packet = null;
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// Wait until there's a packet or we're done.
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while (!done && (packet = queue.poll()) == null) {
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try {
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synchronized (queue) {
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queue.wait();
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}
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}
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catch (InterruptedException ie) {
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// Do nothing
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}
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}
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return packet;
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}
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private void writePackets(Thread thisThread) {
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try {
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// Open the stream.
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openStream();
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// Write out packets from the queue.
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while (!done && (writerThread == thisThread)) {
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Packet packet = nextPacket();
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if (packet != null) {
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synchronized (writer) {
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writer.write(packet.toXML());
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writer.flush();
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// Keep track of the last time a stanza was sent to the server
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lastActive = System.currentTimeMillis();
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}
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}
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}
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// Flush out the rest of the queue.
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try {
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synchronized (writer) {
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while (!queue.isEmpty()) {
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Packet packet = queue.remove();
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writer.write(packet.toXML());
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}
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writer.flush();
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Close the stream.
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try {
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writer.write("</stream:stream>");
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writer.flush();
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}
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catch (Exception e) {
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// Do nothing
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}
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finally {
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try {
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writer.close();
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}
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catch (Exception e) {
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// Do nothing
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}
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}
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}
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catch (IOException ioe){
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if (!done) {
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done = true;
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connection.packetReader.notifyConnectionError(ioe);
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}
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}
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}
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/**
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* Process listeners.
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*/
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private void processListeners(Packet packet) {
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// Clean up null entries in the listeners list if the flag is set. List
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// removes are done seperately so that the main notification process doesn't
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// need to synchronize on the list.
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synchronized (listeners) {
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if (listenersDeleted) {
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for (int i=listeners.size()-1; i>=0; i--) {
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if (listeners.get(i) == null) {
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listeners.remove(i);
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}
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}
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listenersDeleted = false;
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}
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}
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// Notify the listeners of the new sent packet
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int size = listeners.size();
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for (int i=0; i<size; i++) {
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ListenerWrapper listenerWrapper = listeners.get(i);
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if (listenerWrapper != null) {
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listenerWrapper.notifyListener(packet);
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}
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}
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}
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/**
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* Process interceptors. Interceptors may modify the packet that is about to be sent.
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* Since the thread that requested to send the packet will invoke all interceptors, it
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* is important that interceptors perform their work as soon as possible so that the
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* thread does not remain blocked for a long period.
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*
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* @param packet the packet that is going to be sent to the server
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*/
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private void processInterceptors(Packet packet) {
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if (packet != null) {
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// Clean up null entries in the interceptors list if the flag is set. List
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// removes are done seperately so that the main notification process doesn't
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// need to synchronize on the list.
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synchronized (interceptors) {
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if (interceptorDeleted) {
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for (int i=interceptors.size()-1; i>=0; i--) {
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if (interceptors.get(i) == null) {
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interceptors.remove(i);
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}
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}
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interceptorDeleted = false;
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}
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}
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// Notify the interceptors of the new packet to be sent
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int size = interceptors.size();
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for (int i=0; i<size; i++) {
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InterceptorWrapper interceptorWrapper = (InterceptorWrapper)interceptors.get(i);
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if (interceptorWrapper != null) {
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interceptorWrapper.notifyListener(packet);
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}
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}
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}
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}
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/**
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* Sends to the server a new stream element. This operation may be requested several times
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* so we need to encapsulate the logic in one place. This message will be sent while doing
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* TLS, SASL and resource binding.
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*
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* @throws IOException If an error occurs while sending the stanza to the server.
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*/
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void openStream() throws IOException {
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StringBuilder stream = new StringBuilder();
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stream.append("<stream:stream");
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stream.append(" to=\"").append(connection.serviceName).append("\"");
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stream.append(" xmlns=\"jabber:client\"");
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stream.append(" xmlns:stream=\"http://etherx.jabber.org/streams\"");
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stream.append(" version=\"1.0\">");
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writer.write(stream.toString());
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writer.flush();
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}
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/**
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* A wrapper class to associate a packet filter with a listener.
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*/
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protected static class ListenerWrapper {
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private PacketListener packetListener;
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private PacketFilter packetFilter;
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public ListenerWrapper(PacketListener packetListener,
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PacketFilter packetFilter)
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{
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this.packetListener = packetListener;
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this.packetFilter = packetFilter;
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}
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public boolean equals(Object object) {
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if (object == null) {
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return false;
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}
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if (object instanceof ListenerWrapper) {
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return ((ListenerWrapper)object).packetListener.equals(this.packetListener);
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}
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else if (object instanceof PacketListener) {
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return object.equals(this.packetListener);
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}
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return false;
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}
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public void notifyListener(Packet packet) {
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if (packetFilter == null || packetFilter.accept(packet)) {
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packetListener.processPacket(packet);
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}
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}
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}
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/**
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* A wrapper class to associate a packet filter with an interceptor.
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*/
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private static class InterceptorWrapper {
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private PacketInterceptor packetInterceptor;
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private PacketFilter packetFilter;
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public InterceptorWrapper(PacketInterceptor packetInterceptor, PacketFilter packetFilter)
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{
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this.packetInterceptor = packetInterceptor;
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this.packetFilter = packetFilter;
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}
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public boolean equals(Object object) {
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if (object == null) {
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return false;
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}
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if (object instanceof InterceptorWrapper) {
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return ((InterceptorWrapper) object).packetInterceptor
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.equals(this.packetInterceptor);
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}
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else if (object instanceof PacketInterceptor) {
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return object.equals(this.packetInterceptor);
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}
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return false;
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}
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public void notifyListener(Packet packet) {
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if (packetFilter == null || packetFilter.accept(packet)) {
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packetInterceptor.interceptPacket(packet);
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}
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}
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}
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/**
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* A TimerTask that keeps connections to the server alive by sending a space
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* character on an interval.
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*/
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private class KeepAliveTask implements Runnable {
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private int delay;
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private Thread thread;
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public KeepAliveTask(int delay) {
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this.delay = delay;
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}
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protected void setThread(Thread thread) {
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this.thread = thread;
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}
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public void run() {
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try {
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// Sleep 15 seconds before sending first heartbeat. This will give time to
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// properly finish TLS negotiation and then start sending heartbeats.
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Thread.sleep(15000);
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}
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catch (InterruptedException ie) {
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// Do nothing
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}
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while (!done && keepAliveThread == thread) {
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synchronized (writer) {
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// Send heartbeat if no packet has been sent to the server for a given time
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if (System.currentTimeMillis() - lastActive >= delay) {
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try {
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writer.write(" ");
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writer.flush();
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}
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catch (Exception e) {
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// Do nothing
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}
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}
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}
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try {
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// Sleep until we should write the next keep-alive.
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Thread.sleep(delay);
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}
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catch (InterruptedException ie) {
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// Do nothing
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}
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}
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}
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}
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} |