UtilsRMI.java

/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite 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 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite 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 Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package org.evosuite.rmi;

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

import org.evosuite.utils.Randomness;

public class UtilsRMI {

	/**
	 * This is a wrapper over UnicastRemoteObject.exportObject,
	 * as it does not properly handle anonymous/ephemeral ports.
	 * 
	 * In particular, "exportObject(Remote obj)" returns a RemoteStub, and not a Remote reference.  
	 * 
	 * @param obj
	 * @return
	 * @throws RemoteException
	 */
	public static Remote exportObject(Remote obj) throws RemoteException{
		int port = 2000;
		port += Randomness.nextInt(20000);
		
		final int TRIES = 100;
		for(int i=0; i<TRIES; i++){
			try {
				int candidatePort = port+i;
				return UnicastRemoteObject.exportObject(obj,candidatePort);
			} catch (RemoteException e) {								
			}		
		}
		
		return UnicastRemoteObject.exportObject(obj,port);
	}
	
	/**
	 * A registry is created on the "localhost".
	 * But what is the "localhost"? usually, this is a loopback
	 * address 127.0.0.1. But, if there are network interfaces, depending
	 * on the operating system the "localhost" can bind to them.
	 * 
	 * <p>
	 * So, if we start EvoSuite with a connection on (eg WiFi), losing such connection
	 * would mess up EvoSuite. Even worse, if EvoSuite is started from Eclipse, Eclipse
	 * will always use the binding it used at it start! In that case, Eclipse would need
	 * to be restarted each time connection change. 
	 * 
	 * <p>
	 * For these reasons, here we try to force to always bind to 127.0.0.1
	 */		
	public static void ensureRegistryOnLoopbackAddress(){
		 /*
		  *  Here, it does not seem to be possible in a clean way
		  *  to force the biding to 127.0.0.1.
		  *  So we need to modify the property used for it 
		  */
		System.setProperty("java.rmi.server.hostname", "127.0.0.1");
	}

}