threadedevaluator.java

UML设计测试工具

/*
 * USE - UML based specification environment
 * Copyright (C) 1999,2000,2001 Mark Richters, University of Bremen
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* $ProjectHeader: use 2-3-0-release.1 Mon, 12 Sep 2005 20:18:33 +0200 green $ */

package org.tzi.use.uml.ocl.expr;

import java.util.ArrayList;

import org.tzi.use.uml.ocl.expr.MultiplicityViolationException;
import org.tzi.use.uml.ocl.value.Value;
import org.tzi.use.uml.sys.MSystemState;
import org.tzi.use.util.Queue;

/**
 * An evaluator with parallel execution.
 *
 * @version     $ProjectVersion: 2-3-0-release.1 $
 * @author  Mark Richters
 */
class ThreadedEvaluator {
    private static final boolean DEBUG = false;
    //private static final boolean DEBUG = true;

    /**
     * A Controller maintains a set of worker threads each processing
     * a single expression at a time.
     */
    static class Controller extends Thread {
        private Queue fResultValueQueue;
        private ArrayList fExprList;
        MSystemState fSystemState;

        private int fNumWorkers; // number of parallel worker threads
        private Thread[] fWorkers;

        private int fNumJobs;   // number of jobs to process
        private Job[] fJobs;
        private int fNextJob;

        Controller(int numWorkers, Queue resultQueue, 
                   ArrayList exprList, MSystemState systemState) {
            fResultValueQueue = resultQueue;
            fExprList = exprList;
            fSystemState = systemState;
            fNumJobs = fExprList.size();
            fNumWorkers = Math.min(numWorkers, fNumJobs);
            fWorkers = new Thread[fNumWorkers];
            fJobs = new Job[fNumJobs];
            for (int i = 0; i < fNumJobs; i++)
                fJobs[i] = new Job((Expression) exprList.get(i));
        }

        synchronized Job getNextJob() {
            if (fNextJob < fNumJobs )
                return fJobs[fNextJob++];
            else 
                return null;
        }

        public void run() {
            // spawn worker threads
            for (int i = 0; i < fNumWorkers; i++) {
                if (DEBUG )
                    System.err.println("Starting Worker " + i);
                fWorkers[i] = new Worker(this, i);
                fWorkers[i].start();
            }

            // wait on results in fifo order
            for (int i = 0; i < fNumJobs; i++) {
                if (DEBUG )
                    System.err.println("Waiting on result " + i + " of " + fNumJobs);
                Job job = fJobs[i];
                Value v = job.getResult();
                if (DEBUG )
                    System.err.println("Got result " + i + " of " + fNumJobs);
                fResultValueQueue.append(v);
            }

            // wait on worker threads to finish (not really needed)
            //          for (int i = 0; i < fNumWorkers; i++) {
            //          try {
            //              if (DEBUG )
            //              System.err.println("Waiting on Worker " + i);
            //              fWorkers[i].join();
            //              if (DEBUG )
            //              System.err.println("Worker " + i + " joined");
            //          } catch (InterruptedException e) {
            //              System.err.println("Interrupted thread: " + fWorkers[i]);
            //          }
            //          }
        }
    }

    /**
     * A Job is a container for an expression and its result value. It
     * synchronizes access to the result value.  
     */
    static class Job {
        Expression fExpr;   // expression to evaluate
        Value fValue;       // result
        boolean fIgnore = false; // if a MultiplicityViolationException is thrown,
                                 // ignore, that the value is null
        
        Job(Expression expr) {
            fExpr = expr;
        }
        
        synchronized void setIgnore(boolean b) {
            fIgnore = b;
            this.notifyAll();
        }
        
        synchronized void setResult(Value v) {
            fValue = v;
            this.notifyAll();
        }
        
        synchronized Value getResult() {
            while (fValue == null && !fIgnore ) {
                try {
                    this.wait();
                } catch (InterruptedException e) {
                    // ignored
                }
            }
            fIgnore = false;
            return fValue;
        }

        public String toString() {
            return fExpr.toString();
        }
    }

    /**
     * A Worker object receives jobs from the controller and processes
     * them.  
     */
    static class Worker extends Thread {
        private int fNumber;
        private Controller fController;

        public Worker(Controller controller, int i) {
            fController = controller;
            fNumber = i;
        }

        public void run() {
            if (DEBUG )
                System.err.println("Worker " + fNumber + " starts running.");
            int jobsProcessed = 0;
            Job job;
            while ((job = fController.getNextJob()) != null ) {
                if (DEBUG )
                    System.err.println("Worker " + fNumber + " working on job " + job);
                Evaluator evaluator = new Evaluator();

                Value v = null;
                try {
                    v = evaluator.eval(job.fExpr, fController.fSystemState);
                } catch (MultiplicityViolationException ex) {
                    if (DEBUG) {
                        System.err.println("Caught: " + ex.getMessage());
                    }
                    
                    v = null;
                    job.setIgnore(true);
                }

                if (DEBUG )
                    System.err.println("Worker " + fNumber + " finished job " + job);
                job.setResult(v);
                jobsProcessed++;
            }
            if (DEBUG )
                System.err.println("Worker " + fNumber + " finished (" + 
                                   jobsProcessed + " jobs processed)");
        }
    }
}