+++ /dev/null
-/*
- * Copyright (c) 2003-2005 The BISON Project
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * 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 Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- */
-
-package peersim.util;
-
-import java.util.Random;
-import java.lang.Math;
-
-/**
- * Extends the functionality of <code>java.util.Random</code>.
- */
-public class ExtendedRandom extends Random {
-
-private long lastSeed;
-
-// -------------------------------------------------------------------------
-
-/** Calls super constructor. Also stores the seed to be returned by
-{@link #getLastSeed}. */
-public ExtendedRandom(long seed) {
-
- super(seed);
- lastSeed = seed;
-}
-
-// -------------------------------------------------------------------------
-
-/**
- * Extracts the next integer, according to a Poisson distribution.
- *
- * @param mean The mean of the Poisson distribution.
- * @return An integer Poisson extraction.
- */
-public int nextPoisson(double mean) {
-
- double emean = Math.exp(-1 * mean);
- double product = 1;
- int count = 0;
- int result = 0;
- while (product >= emean) {
- product *= nextDouble();
- result = count;
- count++; // keep result one behind
- }
- return result;
-}
-
-// -------------------------------------------------------------------------
-
-/**
-* Implements nextLong(long) the same way nexInt(int) is implemented in
-* java.util.Random.
-* @param n the bound on the random number to be returned. Must be positive.
-* @return a pseudorandom, uniformly distributed long value between 0
-* (inclusive) and n (exclusive).
-*/
-public long nextLong(long n) {
-
- if (n<=0)
- throw new IllegalArgumentException("n must be positive");
-
- if ((n & -n) == n) // i.e., n is a power of 2
- {
- return nextLong()&(n-1);
- }
-
- long bits, val;
- do
- {
- bits = (nextLong()>>>1);
- val = bits % n;
- }
- while(bits - val + (n-1) < 0);
-
- return val;
-}
-
-// -------------------------------------------------------------------------
-
-/** Sets random seed. Calls super method but also stores the seed to be
-returned by {@link #getLastSeed}. */
-public void setSeed( long seed ) {
-
- super.setSeed(seed);
- lastSeed = seed;
-}
-
-// -------------------------------------------------------------------------
-
-/**
-* Returns the last random seed that was set explicitly. Either at
-* construction time or through {@link #setSeed}.
-*/
-public long getLastSeed() { return lastSeed; }
-
-// -------------------------------------------------------------------------
-
-/*
-public static void main(String[] args) {
-
- ExtendedRandom er = new ExtendedRandom(12345678);
- for(int i=0; i<100; ++i)
- System.out.println(er.nextLong(Long.parseLong(args[0])));
-
-}
-*/
-}
-
