001/** 002 * This file is part of the Kompics P2P Framework. 003 * 004 * Copyright (C) 2009 Swedish Institute of Computer Science (SICS) Copyright (C) 005 * 2009 Royal Institute of Technology (KTH) 006 * 007 * Kompics is free software; you can redistribute it and/or modify it under the 008 * terms of the GNU General Public License as published by the Free Software 009 * Foundation; either version 2 of the License, or (at your option) any later 010 * version. 011 * 012 * This program is distributed in the hope that it will be useful, but WITHOUT 013 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 014 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 015 * details. 016 * 017 * You should have received a copy of the GNU General Public License along with 018 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple 019 * Place - Suite 330, Boston, MA 02111-1307, USA. 020 */ 021package se.sics.kompics.simulator.adaptor.distributions; 022 023import java.util.Random; 024 025/** 026 * The <code>LongExponentialDistribution</code> class. 027 * 028 * @author Cosmin Arad {@literal <[email protected]>} 029 * @version $Id: LongExponentialDistribution.java 750 2009-04-02 09:55:01Z Cosmin $ 030 */ 031public class LongExponentialDistribution extends Distribution<Long> { 032 private static final long serialVersionUID = 1760380746716287473L; 033 034 private final Random random; 035 private final double mean; 036 037 public LongExponentialDistribution(long mean, Random random) { 038 super(Type.EXPONENTIAL, Long.class); 039 this.random = random; 040 this.mean = mean; 041 } 042 043 @Override 044 public final Long draw() { 045 double u = random.nextDouble(); 046 return Math.round(-mean * Math.log(1 - u)); 047 } 048}