command.java

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

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

Command.java

Command 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 java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.beans.PropertyChangeListener;

import java.util.Hashtable;

import javax.swing.Action;

import javax.swing.event.SwingPropertyChangeSupport;

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


// COMMAND CLASS


public class Command
    implements Action
{

////////////////////////////////////////////////////////////////////////
//  Constants
////////////////////////////////////////////////////////////////////////

    public static final     String  COMMAND_METHOD_PREFIX   = "do";
    public static final     String  ENABLED_KEY             = "enabled";

    private static final    int PROPERTIES_INITIAL_CAPACITY = 8;

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

    public Command( ActionListener listener )
    {
        this.listener = listener;
        enabled = true;
        properties = new Hashtable<String,Object>( PROPERTIES_INITIAL_CAPACITY );
    }

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

////////////////////////////////////////////////////////////////////////
//  Instance methods : Action interface
////////////////////////////////////////////////////////////////////////

    public void addPropertyChangeListener( PropertyChangeListener listener )
    {
        if ( changeSupport == null )
            changeSupport = new SwingPropertyChangeSupport( this );
        changeSupport.addPropertyChangeListener( listener );
    }

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

    public Object getValue( String key )
    {
        return ( key.equals( ENABLED_KEY ) ? new Boolean( enabled ) : properties.get( key ) );
    }

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

    public boolean isEnabled( )
    {
        return enabled;
    }

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

    public void putValue( String key,
                          Object value )
    {
        Object oldValue = getValue( key );
        if ( key.equals( ENABLED_KEY ) )
        {
            if ( !(value instanceof Boolean) )
                value = Boolean.FALSE;
            enabled = ((Boolean)value).booleanValue( );
        }
        else
        {
            if ( value == null )
                properties.remove( key );
            else
                properties.put( key, value );
        }

        if ( (changeSupport != null) &&
             (((oldValue == null) && (value != null)) ||
              ((oldValue != null) && !oldValue.equals( value ))) )
            changeSupport.firePropertyChange( key, oldValue, value );
    }

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

    public void removePropertyChangeListener( PropertyChangeListener listener )
    {
        if ( changeSupport != null )
            changeSupport.removePropertyChangeListener( listener );
    }

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

    public void setEnabled( boolean enabled )
    {
        boolean oldValue = this.enabled;
        if ( this.enabled != enabled )
        {
            this.enabled = enabled;
            if ( changeSupport != null )
                changeSupport.firePropertyChange( ENABLED_KEY, new Boolean( oldValue ),
                                                  new Boolean( enabled ) );
        }
    }

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

////////////////////////////////////////////////////////////////////////
//  Instance methods : ActionListener interface
////////////////////////////////////////////////////////////////////////

    public void actionPerformed( ActionEvent event )
    {
        listener.actionPerformed( event );
    }

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

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

    public String getMethodName( )
    {
        String key = (String)getValue( Action.ACTION_COMMAND_KEY );
        return ( COMMAND_METHOD_PREFIX + key.substring( 0, 1 ).toUpperCase( ) + key.substring( 1 ) );
    }

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

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

    private ActionListener              listener;
    private boolean                     enabled;
    private Hashtable<String,Object>    properties;
    private SwingPropertyChangeSupport  changeSupport;

}

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