Initial version. SMACK-155

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@4537 b35dd754-fafc-0310-a699-88a17e54d16e

source/org/jivesoftware/smackx/muc/ConnectionDetachedPacketCollector.java

@@ -0,0 +1,135 @@
+/**
+ * $RCSfile$
+ * $Revision: 2779 $
+ * $Date: 2005-09-05 17:00:45 -0300 (Mon, 05 Sep 2005) $
+ *
+ * Copyright 2003-2006 Jive Software.
+ *
+ * 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.jivesoftware.smackx.muc;
+
+import org.jivesoftware.smack.packet.Packet;
+
+import java.util.LinkedList;
+
+/**
+ * A variant of the {@link org.jivesoftware.smack.PacketCollector} class
+ * that does not force attachment to an <code>XMPPConnection</code>
+ * on creation and no filter is required. Used to collect message
+ * packets targeted to a group chat room.
+ *
+ * @author Larry Kirschner
+ */
+class ConnectionDetachedPacketCollector {
+    /**
+     * Max number of packets that any one collector can hold. After the max is
+     * reached, older packets will be automatically dropped from the queue as
+     * new packets are added.
+     */
+    private static final int MAX_PACKETS = 65536;
+
+    private LinkedList<Packet> resultQueue;
+
+    /**
+     * Creates a new packet collector. If the packet filter is <tt>null</tt>, then
+     * all packets will match this collector.
+     */
+    public ConnectionDetachedPacketCollector() {
+        this.resultQueue = new LinkedList<Packet>();
+    }
+
+    /**
+     * Polls to see if a packet is currently available and returns it, or
+     * immediately returns <tt>null</tt> if no packets are currently in the
+     * result queue.
+     *
+     * @return the next packet result, or <tt>null</tt> if there are no more
+     *      results.
+     */
+    public synchronized Packet pollResult() {
+        if (resultQueue.isEmpty()) {
+            return null;
+        }
+        else {
+            return resultQueue.removeLast();
+        }
+    }
+
+    /**
+     * Returns the next available packet. The method call will block (not return)
+     * until a packet is available.
+     *
+     * @return the next available packet.
+     */
+    public synchronized Packet nextResult() {
+        // Wait indefinitely until there is a result to return.
+        while (resultQueue.isEmpty()) {
+            try {
+                wait();
+            }
+            catch (InterruptedException ie) {
+                // Ignore.
+            }
+        }
+        return resultQueue.removeLast();
+    }
+
+    /**
+     * Returns the next available packet. The method call will block (not return)
+     * until a packet is available or the <tt>timeout</tt> has elapased. If the
+     * timeout elapses without a result, <tt>null</tt> will be returned.
+     *
+     * @param timeout the amount of time to wait for the next packet (in milleseconds).
+     * @return the next available packet.
+     */
+    public synchronized Packet nextResult(long timeout) {
+        // Wait up to the specified amount of time for a result.
+        if (resultQueue.isEmpty()) {
+            try {
+                wait(timeout);
+            }
+            catch (InterruptedException ie) {
+                // Ignore.
+            }
+        }
+        // If still no result, return null.
+        if (resultQueue.isEmpty()) {
+            return null;
+        }
+        else {
+            return resultQueue.removeLast();
+        }
+    }
+
+    /**
+     * Processes a packet to see if it meets the criteria for this packet collector.
+     * If so, the packet is added to the result queue.
+     *
+     * @param packet the packet to process.
+     */
+    protected synchronized void processPacket(Packet packet) {
+        if (packet == null) {
+            return;
+        }
+        // If the max number of packets has been reached, remove the oldest one.
+        if (resultQueue.size() == MAX_PACKETS) {
+            resultQueue.removeLast();
+        }
+        // Add the new packet.
+        resultQueue.addFirst(packet);
+        // Notify waiting threads a result is available.
+        notifyAll();
+    }
+}