SocketUtil.java

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.rubypeople.rdt.core;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;

/**
 * Utility class to find a port to debug on.
 */
public class SocketUtil
{

	/**
	 * Returns a free port number on localhost, or -1 if unable to find a free port.
	 * 
	 * @return a free port number on localhost, or -1 if unable to find a free port
	 * @since 0.7
	 */
	public static int findFreePort()
	{
		ServerSocket socket = null;
		try
		{
			socket = new ServerSocket(0);
			return socket.getLocalPort();
		}
		catch (IOException e)
		{
		}
		finally
		{
			if (socket != null)
			{
				try
				{
					socket.close();
				}
				catch (IOException e)
				{
				}
			}
		}
		return -1;
	}

	public static boolean portFree(int port)
	{
		return portFree("127.0.0.1", port);
	}
	
	public static boolean portFree(String host, int port)
	{
		ServerSocket socket = null;
		try
		{
			socket = new ServerSocket();
			socket.setReuseAddress(true);
			socket.bind(new InetSocketAddress(host, port));
		}
		catch (Exception e)
		{
			// ignore
			return false;
		}
		finally
		{
			try
			{
				if (socket != null)
					socket.close();
			}
			catch (IOException e)
			{
				// ignore
			}
		}
		return true;
	}

}