src/jlibrtp/ParticipantDatabase.java
changeset 13 e684f11070d5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jlibrtp/ParticipantDatabase.java	Sat Mar 14 22:15:41 2009 +0100
@@ -0,0 +1,256 @@
+/**
+ * Java RTP Library (jlibrtp)
+ * Copyright (C) 2006 Arne Kepp
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+package jlibrtp;
+
+import java.util.*;
+import java.util.concurrent.*;
+
+/**
+ * The participant database maintains three hashtables with participants.
+ * 
+ * The key issue is to be fast for operations that happen every time an
+ * RTP packet is sent or received. We allow linear searching in cases 
+ * where we need to update participants with information.
+ * 
+ * The keying is therefore usually the SSRC. In cases where we have the
+ * cname, but no SSRC is known (no SDES packet has been received), a
+ * simple hash i calculated based on the CNAME. The RTCP code should,
+ * when receiving SDES packets, check whether the participant is known
+ * and update the copy in this database with SSRC if needed.
+ * 
+ * @author Arne Kepp
+ */
+public class ParticipantDatabase {
+	/** The parent RTP Session */
+	RTPSession rtpSession = null;
+	/** 
+	 * A linked list to hold participants explicitly added by the application
+	 * In unicast mode this is the list used for RTP and RTCP transmission, 
+	 * in multicast it should not be in use. 
+	 */
+	LinkedList<Participant> receivers = new LinkedList<Participant>();	
+	/** 
+	 * The hashtable holds participants added through received RTP and RTCP packets,
+	 * as well as participants that have been linked to an SSRC by ip address (in unicast mode).
+	 */
+	ConcurrentHashMap<Long,Participant> ssrcTable = new ConcurrentHashMap<Long,Participant>();
+	
+	/**
+	 * Simple constructor
+	 * 
+	 * @param parent parent RTPSession
+	 */
+	protected ParticipantDatabase(RTPSession parent) {
+		rtpSession = parent;
+	}
+	
+	/**
+	 * 
+	 * @param cameFrom 0: Application, 1: RTP packet, 2: RTCP
+	 * @param p the participant
+	 * @return 0 if okay, -1 if not 
+	 */
+	protected int addParticipant(int cameFrom, Participant p) {
+		//Multicast or not?
+		if(this.rtpSession.mcSession) {
+			return this.addParticipantMulticast(cameFrom, p);
+		} else {
+			return this.addParticipantUnicast(cameFrom, p);
+		}
+		
+	}
+	
+	/**
+	 * Add a multicast participant to the database
+	 * 
+	 * @param cameFrom 0: Application, 1,2: discovered through RTP or RTCP
+	 * @param p the participant to add
+	 * @return 0 if okay, -2 if redundant, -1 if adding participant to multicast
+	 */
+	private int addParticipantMulticast(int cameFrom, Participant p) {
+		if( cameFrom == 0) {
+			System.out.println("ParticipantDatabase.addParticipant() doesnt expect" 
+					+ " application to add participants to multicast session.");
+			return -1;
+		} else {
+			// Check this one is not redundant
+			if(this.ssrcTable.contains(p.ssrc)) {
+				System.out.println("ParticipantDatabase.addParticipant() SSRC "
+						+"already known " + Long.toString(p.ssrc));
+				return -2;
+			} else {
+				this.ssrcTable.put(p.ssrc, p);
+				return 0;
+			}
+		}
+	}
+	
+	/**
+	 * Add a unicast participant to the database
+	 * 
+	 * Result will be reported back through tpSession.appIntf.userEvent
+	 * 
+	 * @param cameFrom 0: Application, 1,2: discovered through RTP or RTCP
+	 * @param p the participant to add
+	 * @return 0 if new, 1 if 
+	 */
+	private int addParticipantUnicast(int cameFrom, Participant p) {
+		if(cameFrom == 0) {
+			//Check whether there is a match in the ssrcTable
+			boolean notDone = true;
+			
+			Enumeration<Participant> enu = this.ssrcTable.elements();
+			while(notDone && enu.hasMoreElements()) {
+				Participant part = enu.nextElement();
+				if(part.unexpected && 
+						(part.rtcpReceivedFromAddress.equals(part.rtcpAddress.getAddress()) 
+						|| part.rtpReceivedFromAddress.equals(part.rtpAddress.getAddress()))) {
+					
+					part.rtpAddress = p.rtpAddress;
+					part.rtcpAddress = p.rtcpAddress;
+					part.unexpected = false;
+
+					//Report the match back to the application
+					Participant[] partArray = {part};
+					this.rtpSession.appIntf.userEvent(5, partArray);
+					
+					notDone = false;
+					p = part;
+				}
+			}
+
+			//Add to the table of people that we send packets to
+			this.receivers.add(p);
+			return 0;
+			
+		} else {
+			//Check whether there's a match in the receivers table
+			boolean notDone = true;
+			//System.out.println("GOT " + p.cname);
+			Iterator<Participant> iter = this.receivers.iterator();
+			
+			while(notDone && iter.hasNext()) {
+				Participant part = iter.next();
+				
+				//System.out.println(part.rtpAddress.getAddress().toString()
+				//		+ " " + part.rtcpAddress.getAddress().toString() 
+				//		+ " " + p.rtpReceivedFromAddress.getAddress().toString()
+				//		+ " " + p.rtcpReceivedFromAddress.getAddress().toString());
+				
+				//System.out.println(" HUUHHHH?  " + p.rtcpReceivedFromAddress.getAddress().equals(part.rtcpAddress.getAddress()));
+				if((cameFrom == 1 && p.rtpReceivedFromAddress.getAddress().equals(part.rtpAddress.getAddress()))
+					|| (cameFrom == 2 && p.rtcpReceivedFromAddress.getAddress().equals(part.rtcpAddress.getAddress()))) {
+					
+					part.rtpReceivedFromAddress = p.rtpReceivedFromAddress;
+					part.rtcpReceivedFromAddress = p.rtcpReceivedFromAddress;
+					
+					// Move information
+					part.ssrc = p.ssrc;
+					part.cname = p.cname;
+					part.name = p.name;
+					part.loc = p.loc;
+					part.phone = p.phone;
+					part.email = p.email;
+					part.note = p.note;
+					part.tool = p.tool;
+					part.priv = p.priv;
+					
+					this.ssrcTable.put(part.ssrc, part);
+					
+					//Report the match back to the application
+					Participant[] partArray = {part};
+					this.rtpSession.appIntf.userEvent(5, partArray);
+					return 0;
+				}
+			}
+			
+			// No match? ok
+			this.ssrcTable.put(p.ssrc, p);				
+			return 0;
+		}
+	}
+	
+	/**
+	 * Remove a participant from all tables
+	 * 
+	 * @param p the participant to be removed
+	 */
+	protected void removeParticipant(Participant p) {
+		if(! this.rtpSession.mcSession)
+			this.receivers.remove(p);
+		
+		this.ssrcTable.remove(p.ssrc, p);
+	}
+		
+	/**
+	 * Find a participant based on the ssrc
+	 * 
+	 * @param ssrc of the participant to be found
+	 * @return the participant, null if unknonw
+	 */
+	protected Participant getParticipant(long ssrc) {
+		Participant p = null;
+		p = ssrcTable.get(ssrc);
+		return p; 
+	}
+	
+	/**
+	 * Iterator for all the unicast receivers.
+	 * 
+	 * This one is used by both RTP for sending packets, as well as RTCP.
+	 * 
+	 * @return iterator for unicast participants
+	 */
+	protected Iterator<Participant> getUnicastReceivers() {
+		if(! this.rtpSession.mcSession) {
+			return this.receivers.iterator();
+		} else {
+			System.out.println("Request for ParticipantDatabase.getUnicastReceivers in multicast session");
+			return null;
+		}
+	}
+	
+	/**
+	 * Enumeration of all the participants with known ssrcs.
+	 * 
+	 * This is primarily used for sending packets in multicast sessions.
+	 * 
+	 * @return enumerator with all the participants with known SSRCs
+	 */
+	protected Enumeration<Participant> getParticipants() {
+		return this.ssrcTable.elements();
+	}
+	
+	protected void debugPrint() {
+		System.out.println("   ParticipantDatabase.debugPrint()");
+		Participant p;
+		Enumeration enu = ssrcTable.elements();
+		while(enu.hasMoreElements()) {
+			p = (Participant) enu.nextElement();
+			System.out.println("           ssrcTable ssrc:"+p.ssrc+" cname:"+p.cname
+					+" loc:"+p.loc+" rtpAddress:"+p.rtpAddress+" rtcpAddress:"+p.rtcpAddress);
+		}
+		
+		Iterator<Participant> iter = receivers.iterator();
+		while(iter.hasNext()) {
+			p = iter.next();
+			System.out.println("           receivers: "+p.rtpAddress.toString());
+		}
+	}
+}