/*
* Created on 27-May-2004
* Created by Paul Gardner
* Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package org.gudy.azureus2.core3.util;
/**
* @author parg
*
*/
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.*;
public class
IPToHostNameResolver
{
static protected AEThread2 resolver_thread;
static protected List request_queue = new ArrayList();
static protected AEMonitor request_mon = new AEMonitor( "IPToHostNameResolver" );
static protected AESemaphore request_semaphore = new AESemaphore("IPToHostNameResolver");
public static IPToHostNameResolverRequest
addResolverRequest(
String ip,
IPToHostNameResolverListener l )
{
try{
request_mon.enter();
IPToHostNameResolverRequest request = new IPToHostNameResolverRequest( ip, l );
request_queue.add( request );
request_semaphore.release();
if ( resolver_thread == null ){
resolver_thread =
new AEThread2("IPToHostNameResolver", true )
{
public void
run()
{
while(true){
try{
request_semaphore.reserve(30000);
IPToHostNameResolverRequest req;
try{
request_mon.enter();
if ( request_queue.isEmpty()){
resolver_thread = null;
break;
}
req = (IPToHostNameResolverRequest)request_queue.remove(0);
}finally{
request_mon.exit();
}
IPToHostNameResolverListener listener = req.getListener();
// if listener is null the request has been cancelled
if ( listener != null ){
try{
InetAddress addr = InetAddress.getByName( req.getIP());
req.getListener().IPResolutionComplete( addr.getHostName(), true );
}catch( Throwable e ){
req.getListener().IPResolutionComplete( req.getIP(), false );
}
}
}catch( Throwable e ){
Debug.printStackTrace( e );
}
}
}
};
resolver_thread.start();
}
return( request );
}finally{
request_mon.exit();
}
}
public static String
syncResolve(
String ip,
int timeout )
throws Exception
{
final AESemaphore sem = new AESemaphore( "IPToHostNameREsolver:sync" );
final Object[] result = {null};
addResolverRequest(
ip,
new IPToHostNameResolverListener()
{
public void
IPResolutionComplete(
String resolved_ip,
boolean succeeded )
{
try{
synchronized( result ){
if ( succeeded ){
result[0] = resolved_ip;
}
}
}finally{
sem.release();
}
}
});
if ( !sem.reserve( timeout )){
throw( new Exception( "Timeout" ));
}
synchronized( result ){
if ( result[0] != null ){
return((String)result[0]);
}
throw( new UnknownHostException( ip ));
}
}
}