operation.java

FuncPlotter is a combined Java application and applet for displaying two-dimensional plots of explic

/*====================================================================*\

Operation.java

Operation class.

------------------------------------------------------------------------

This file is part of FuncPlotter, a combined Java application and applet
for plotting explicit functions in one variable.
Copyright 2005-2007 Andy Morgan-Richards.

FuncPlotter 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 3 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, see <http://www.gnu.org/licenses/>.

\*====================================================================*/


// PACKAGE


package util;

//----------------------------------------------------------------------


// IMPORTS


import exception.AppException;
import exception.TerminatedException;

import gui.ProgressView;

import java.util.ArrayList;
import java.util.List;

//----------------------------------------------------------------------


// OPERATION CLASS


public abstract class Operation
    implements Runnable
{

////////////////////////////////////////////////////////////////////////
//  Constructors
////////////////////////////////////////////////////////////////////////

    protected Operation( )
    {
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Static initialiser
////////////////////////////////////////////////////////////////////////

    static
    {
        threads = new ArrayList<Thread>( );
    }

////////////////////////////////////////////////////////////////////////
//  Class methods
////////////////////////////////////////////////////////////////////////

    public static synchronized boolean isException( )
    {
        return ( exception != null );
    }

    //------------------------------------------------------------------

    public static synchronized AppException getException( )
    {
        return exception;
    }

    //------------------------------------------------------------------

    public static synchronized boolean isTerminated( )
    {
        return terminated;
    }

    //------------------------------------------------------------------

    public static synchronized boolean isExceptionOrTerminated( )
    {
        return ( (exception != null) || terminated );
    }

    //------------------------------------------------------------------

    public static synchronized ProgressView getProgressView( )
    {
        return progressView;
    }

    //------------------------------------------------------------------

    public static synchronized void setException( AppException exception,
                                                  boolean      override )
    {
        if ( override || (Operation.exception == null) )
            Operation.exception = exception;
    }

    //------------------------------------------------------------------

    public static synchronized void setTerminated( boolean terminate )
    {
        terminated = terminate;
    }

    //------------------------------------------------------------------

    public static synchronized void setProgressView( ProgressView progressView )
    {
        Operation.progressView = progressView;
    }

    //------------------------------------------------------------------

    public static synchronized int getNumThreads( )
    {
        return threads.size( );
    }

    //------------------------------------------------------------------

    public static synchronized int addThread( Thread thread )
    {
        threads.add( thread );
        return threads.size( );
    }

    //------------------------------------------------------------------

    public static synchronized void removeThread( )
    {
        threads.remove( Thread.currentThread( ) );
        if ( threads.isEmpty( ) )
        {
            if ( progressView != null )
            {
                progressView.close( );
                progressView = null;
            }
        }
    }

    //------------------------------------------------------------------

    public static synchronized void throwOnException( )
        throws AppException
    {
        if ( exception != null )
            throw exception;
    }

    //------------------------------------------------------------------

    public static synchronized void throwOnTerminated( )
        throws TerminatedException
    {
        if ( terminated )
            throw new TerminatedException( );
    }

    //------------------------------------------------------------------

    public static synchronized void throwOnExceptionOrTerminated( )
        throws AppException
    {
        throwOnException( );
        throwOnTerminated( );
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Instance methods
////////////////////////////////////////////////////////////////////////

    public boolean start( )
    {
        if ( terminated )
            return false;
        Thread thread = new Thread( this, "app-" + getClass( ).getName( ) + "-" + threadId++ );
        thread.setDaemon( true );
        if ( addThread( thread ) == 1 )
            primary = true;
        thread.start( );
        return true;
    }

    //------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////
//  Class variables
////////////////////////////////////////////////////////////////////////

    private static  AppException    exception;
    private static  boolean         terminated;
    private static  ProgressView    progressView;
    private static  int             threadId;
    private static  List<Thread>    threads;

////////////////////////////////////////////////////////////////////////
//  Instance variables
////////////////////////////////////////////////////////////////////////

    private boolean primary;

}

//----------------------------------------------------------------------