001    /*
002     * Copyright (C) 2008-2010 by Holger Arndt
003     *
004     * This file is part of the Universal Java Matrix Package (UJMP).
005     * See the NOTICE file distributed with this work for additional
006     * information regarding copyright ownership and licensing.
007     *
008     * UJMP is free software; you can redistribute it and/or modify
009     * it under the terms of the GNU Lesser General Public License as
010     * published by the Free Software Foundation; either version 2
011     * of the License, or (at your option) any later version.
012     *
013     * UJMP is distributed in the hope that it will be useful,
014     * but WITHOUT ANY WARRANTY; without even the implied warranty of
015     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
016     * GNU Lesser General Public License for more details.
017     *
018     * You should have received a copy of the GNU Lesser General Public
019     * License along with UJMP; if not, write to the
020     * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
021     * Boston, MA  02110-1301  USA
022     */
023    
024    package org.ujmp.core.util.concurrent;
025    
026    import java.util.concurrent.Callable;
027    import java.util.concurrent.Future;
028    import java.util.concurrent.ThreadPoolExecutor;
029    
030    import org.ujmp.core.util.UJMPSettings;
031    
032    public abstract class PForEquidistant {
033    
034            private final Object[] objects;
035    
036            public PForEquidistant(final int threads, final int first, final int last,
037                            final Object... objects) {
038                    this.objects = objects;
039    
040                    if (threads < 2) {
041                            for (int i = first; i <= last; i++) {
042                                    step(i);
043                            }
044                    } else {
045                            final ThreadPoolExecutor es = UJMPThreadPoolExecutor.getInstance(threads);
046    
047                            final Future<?>[] list = new Future[threads];
048    
049                            for (int i = 0; i < threads; i++) {
050                                    list[i] = es.submit(new StepCallable(first + i, last, threads));
051                            }
052    
053                            for (Future<?> f : list) {
054                                    try {
055                                            f.get();
056                                    } catch (Exception e) {
057                                            e.printStackTrace();
058                                    }
059                            }
060                    }
061            }
062    
063            public PForEquidistant(final int first, final int last, final Object... objects) {
064                    this(UJMPSettings.getNumberOfThreads(), first, last, objects);
065            }
066    
067            public abstract void step(final int i);
068    
069            public final Object getObject(final int i) {
070                    return objects[i];
071            }
072    
073            class StepCallable implements Callable<Object> {
074                    private final int first;
075                    private final int last;
076                    private final int stepsize;
077    
078                    public StepCallable(final int first, final int last, final int stepsize) {
079                            this.first = first;
080                            this.last = last;
081                            this.stepsize = stepsize;
082                    }
083    
084                    public final Void call() throws Exception {
085                            try {
086                                    for (int i = first; i <= last; i += stepsize) {
087                                            step(i);
088                                    }
089                            } catch (Exception e) {
090                                    e.printStackTrace();
091                            }
092                            return null;
093                    }
094    
095            }
096    
097    }