101 lines
3.5 KiB
Java
101 lines
3.5 KiB
Java
/*
|
|
* Copyright (c) 2014, Friedrich-Alexander University Erlangen-Nuremberg.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the university nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
*/
|
|
|
|
package org.contikios.cooja;
|
|
|
|
import java.util.Random;
|
|
|
|
/**
|
|
* This ensures that the functions of the random number generator are
|
|
* only called by the the thread initializing a simulation or the
|
|
* simulation thread itself.
|
|
* Rationale: By allowing another thread to use the random number
|
|
* generator concurrency is introduced, thus it can not be guaranteed
|
|
* that simulations are reproducible.
|
|
*
|
|
*/
|
|
public class SafeRandom extends Random {
|
|
|
|
Simulation sim = null;
|
|
Thread initThread = null;
|
|
Boolean simStarted = false;
|
|
|
|
private void assertSimThread() {
|
|
// sim can be null, because setSeed is called by the super-constructor.
|
|
if(sim == null) return;
|
|
|
|
// If we are in the simulation thread, everything is fine (the default)
|
|
if(sim.isSimulationThread()) {
|
|
simStarted = true;
|
|
return;
|
|
}
|
|
|
|
// Simulation has not started yet. Allow one initialisation thread.
|
|
if(!simStarted) {
|
|
if(initThread == null) initThread = Thread.currentThread();
|
|
if(Thread.currentThread() == initThread ) return;
|
|
}
|
|
|
|
//This is done via the GUI - reproducibility is lost anyway!
|
|
if(javax.swing.SwingUtilities.isEventDispatchThread()) return;
|
|
|
|
// Some other threads seems to access the PNRG. This must not happen.
|
|
throw new RuntimeException("A random-function was not called from the simulation thread. This can break things!");
|
|
|
|
}
|
|
|
|
public SafeRandom(Simulation sim) {
|
|
// assertSimThread is called by the super-constructor.
|
|
super();
|
|
this.sim = sim;
|
|
}
|
|
|
|
public SafeRandom(Simulation sim, long seed) {
|
|
// assertSimThread is called by the super-constructor.
|
|
super(seed);
|
|
this.sim = sim;
|
|
}
|
|
|
|
synchronized public void setSeed(long seed) {
|
|
assertSimThread();
|
|
super.setSeed(seed);
|
|
}
|
|
|
|
/*
|
|
* This function is called by all functions returning random numbers
|
|
* @see java.util.Random#next(int)
|
|
*/
|
|
protected int next(int bits) {
|
|
assertSimThread();
|
|
return super.next(bits);
|
|
}
|
|
|
|
}
|