/*
* @(#) $Id: DatagramAcceptor.java 327113 2005-10-21 06:59:15Z trustin $
*
* Copyright 2004 The Apache Software Foundation
*
* 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.apache.mina.io.datagram;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.apache.mina.common.ByteBuffer;
import org.apache.mina.io.IoAcceptor;
import org.apache.mina.io.IoFilterChain;
import org.apache.mina.io.IoHandler;
import org.apache.mina.io.IoSession;
import org.apache.mina.io.IoSessionManagerFilterChain;
import org.apache.mina.util.ExceptionUtil;
import org.apache.mina.util.Queue;
/**
* {@link IoAcceptor} for datagram transport (UDP/IP).
*
* @author The Apache Directory Project (dev@directory.apache.org)
* @version $Rev: 327113 $, $Date: 2005-10-21 15:59:15 +0900 $
*/
public class DatagramAcceptor extends DatagramSessionManager implements IoAcceptor
{
private static volatile int nextId = 0;
private final IoSessionManagerFilterChain filters =
new DatagramSessionManagerFilterChain( this );
private final int id = nextId ++ ;
private Selector selector;
private final Map channels = new HashMap();
private final Queue registerQueue = new Queue();
private final Queue cancelQueue = new Queue();
private final Queue flushingSessions = new Queue();
private Worker worker;
/**
* Creates a new instance.
*/
public DatagramAcceptor()
{
}
public void bind( SocketAddress address, IoHandler handler )
throws IOException
{
if( address == null )
throw new NullPointerException( "address" );
if( handler == null )
throw new NullPointerException( "handler" );
if( !( address instanceof InetSocketAddress ) )
throw new IllegalArgumentException( "Unexpected address type: "
+ address.getClass() );
if( ( ( InetSocketAddress ) address ).getPort() == 0 )
throw new IllegalArgumentException( "Unsupported port number: 0" );
RegistrationRequest request = new RegistrationRequest( address, handler );
synchronized( this )
{
synchronized( registerQueue )
{
registerQueue.push( request );
}
startupWorker();
}
selector.wakeup();
synchronized( request )
{
while( !request.done )
{
try
{
request.wait();
}
catch( InterruptedException e )
{
}
}
}
if( request.exception != null )
{
ExceptionUtil.throwException( request.exception );
}
}
public void unbind( SocketAddress address )
{
if( address == null )
throw new NullPointerException( "address" );
CancellationRequest request = new CancellationRequest( address );
synchronized( this )
{
try
{
startupWorker();
}
catch( IOException e )
{
// IOException is thrown only when Worker thread is not
// running and failed to open a selector. We simply throw
// IllegalArgumentException here because we can simply
// conclude that nothing is bound to the selector.
throw new IllegalArgumentException( "Address not bound: " + address );
}
synchronized( cancelQueue )
{
cancelQueue.push( request );
}
}
selector.wakeup();
synchronized( request )
{
while( !request.done )
{
try
{
request.wait();
}
catch( InterruptedException e )
{
}
}
}
if( request.exception != null )
{
request.exception.fillInStackTrace();
throw request.exception;
}
}
public IoSession newSession( SocketAddress remoteAddress, SocketAddress localAddress )
{
if( remoteAddress == null )
{
throw new NullPointerException( "remoteAddress" );
}
if( localAddress == null )
{
throw new NullPointerException( "localAddress" );
}
Selector selector = this.selector;
DatagramChannel ch = ( DatagramChannel ) channels.get( localAddress );
if( selector == null || ch == null )
{
throw new IllegalArgumentException( "Unknown localAddress: " + localAddress );
}
SelectionKey key = ch.keyFor( selector );
if( key == null )
{
throw new IllegalArgumentException( "Unknown lodalAddress: " + localAddress );
}
RegistrationRequest req = ( RegistrationRequest ) key.attachment();
DatagramSession s = new DatagramSession( filters, ch, req.handler );
s.setRemoteAddress( remoteAddress );
s.setSelectionKey( key );
try
{
req.handler.sessionCreated( s );
}
catch( Throwable t )
{
exceptionMonitor.exceptionCaught( this, t );
}
return s;
}
private synchronized void startupWorker() throws IOException
{
if( worker == null )
{
selector = Selector.open();
worker = new Worker();
worker.start();
}
}
void flushSession( DatagramSession session )
{
scheduleFlush( session );
selector.wakeup();
}
void closeSession( DatagramSession session )
{
}
private void scheduleFlush( DatagramSession session )
{
synchronized( flushingSessions )
{
flushingSessions.push( session );
}
}
private class Worker extends Thread
{
public Worker()
{
super( "DatagramAcceptor-" + id );
}
public void run()
{
for( ;; )
{
try
{
int nKeys = selector.select();
registerNew();
if( nKeys > 0 )
{
processReadySessions( selector.selectedKeys() );
}
flushSessions();
cancelKeys();
if( selector.keys().isEmpty() )
{
synchronized( DatagramAcceptor.this )
{
if( selector.keys().isEmpty() &&
registerQueue.isEmpty() &&
cancelQueue.isEmpty() )
{
worker = null;
try
{
selector.close();
}
catch( IOException e )
{
exceptionMonitor.exceptionCaught( DatagramAcceptor.this, e );
}
finally
{
selector = null;
}
break;
}
}
}
}
catch( IOException e )
{
exceptionMonitor.exceptionCaught( DatagramAcceptor.this,
e );
try
{
Thread.sleep( 1000 );
}
catch( InterruptedException e1 )
{
}
}
}
}
}
private void processReadySessions( Set keys )
{
Iterator it = keys.iterator();
while( it.hasNext() )
{
SelectionKey key = ( SelectionKey ) it.next();
it.remove();
DatagramChannel ch = ( DatagramChannel ) key.channel();
RegistrationRequest req = ( RegistrationRequest ) key.attachment();
DatagramSession session = new DatagramSession(
filters, ch, req.handler );
session.setSelectionKey( key );
try
{
req.handler.sessionCreated( session );
if( key.isReadable() )
{
readSession( session );
}
if( key.isWritable() )
{
scheduleFlush( session );
}
}
catch( Throwable t )
{
exceptionMonitor.exceptionCaught( this, t );
}
}
}
private void readSession( DatagramSession session )
{
ByteBuffer readBuf = ByteBuffer.allocate( 2048 );
try
{
SocketAddress remoteAddress = session.getChannel().receive(
readBuf.buf() );
if( remoteAddress != null )
{
readBuf.flip();
session.setRemoteAddress( remoteAddress );
ByteBuffer newBuf = ByteBuffer.allocate( readBuf.limit() );
newBuf.put( readBuf );
newBuf.flip();
session.increaseReadBytes( newBuf.remaining() );
filters.dataRead( session, newBuf );
}
}
catch( IOException e )
{
filters.exceptionCaught( session, e );
}
finally
{
readBuf.release();
}
}
private void flushSessions()
{
if( flushingSessions.size() == 0 )
return;
for( ;; )
{
DatagramSession session;
synchronized( flushingSessions )
{
session = ( DatagramSession ) flushingSessions.pop();
}
if( session == null )
break;
try
{
flush( session );
}
catch( IOException e )
{
session.getManagerFilterChain().exceptionCaught( session, e );
}
}
}
private void flush( DatagramSession session ) throws IOException
{
DatagramChannel ch = session.getChannel();
Queue writeBufferQueue = session.getWriteBufferQueue();
Queue writeMarkerQueue = session.getWriteMarkerQueue();
ByteBuffer buf;
Object marker;
for( ;; )
{
synchronized( writeBufferQueue )
{
buf = ( ByteBuffer ) writeBufferQueue.first();
marker = writeMarkerQueue.first();
}
if( buf == null )
break;
if( buf.remaining() == 0 )
{
// pop and fire event
synchronized( writeBufferQueue )
{
writeBufferQueue.pop();
writeMarkerQueue.pop();
}
try
{
buf.release();
}
catch( IllegalStateException e )
{
session.getManagerFilterChain().exceptionCaught( session, e );
}
session.increaseWrittenWriteRequests();
session.getManagerFilterChain().dataWritten( session, marker );
continue;
}
int writtenBytes = ch
.send( buf.buf(), session.getRemoteAddress() );
SelectionKey key = session.getSelectionKey();
if( writtenBytes == 0 )
{
// Kernel buffer is full
key.interestOps( key.interestOps() | SelectionKey.OP_WRITE );
}
else if( writtenBytes > 0 )
{
key.interestOps( key.interestOps()
& ( ~SelectionKey.OP_WRITE ) );
// pop and fire event
synchronized( writeBufferQueue )
{
writeBufferQueue.pop();
writeMarkerQueue.pop();
}
session.increaseWrittenBytes( writtenBytes );
session.increaseWrittenWriteRequests();
session.getManagerFilterChain().dataWritten( session, marker );
}
}
}
private void registerNew()
{
if( registerQueue.isEmpty() )
return;
for( ;; )
{
RegistrationRequest req;
synchronized( registerQueue )
{
req = ( RegistrationRequest ) registerQueue.pop();
}
if( req == null )
break;
DatagramChannel ch = null;
try
{
ch = DatagramChannel.open();
ch.configureBlocking( false );
ch.socket().bind( req.address );
ch.register( selector, SelectionKey.OP_READ, req );
channels.put( req.address, ch );
}
catch( Throwable t )
{
req.exception = t;
}
finally
{
synchronized( req )
{
req.done = true;
req.notify();
}
if( ch != null && req.exception != null )
{
try
{
ch.close();
}
catch( Throwable e )
{
exceptionMonitor.exceptionCaught( this, e );
}
}
}
}
}
private void cancelKeys()
{
if( cancelQueue.isEmpty() )
return;
for( ;; )
{
CancellationRequest request;
synchronized( cancelQueue )
{
request = ( CancellationRequest ) cancelQueue.pop();
}
if( request == null )
{
break;
}
DatagramChannel ch = ( DatagramChannel ) channels.remove( request.address );
// close the channel
try
{
if( ch == null )
{
request.exception = new IllegalArgumentException(
"Address not bound: " + request.address );
}
else
{
SelectionKey key = ch.keyFor( selector );
key.cancel();
selector.wakeup(); // wake up again to trigger thread death
ch.close();
}
}
catch( Throwable t )
{
exceptionMonitor.exceptionCaught( this, t );
}
finally
{
synchronized( request )
{
request.done = true;
request.notify();
}
}
}
}
public IoFilterChain getFilterChain()
{
return filters;
}
private static class RegistrationRequest
{
private final SocketAddress address;
private final IoHandler handler;
private Throwable exception;
private boolean done;
private RegistrationRequest( SocketAddress address, IoHandler handler )
{
this.address = address;
this.handler = handler;
}
}
private static class CancellationRequest
{
private final SocketAddress address;
private boolean done;
private RuntimeException exception;
private CancellationRequest( SocketAddress address )
{
this.address = address;
}
}
}