abstracttextfield.java

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

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

AbstractTextField.java

Abstract text field 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 textfield;

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


// IMPORTS


import java.awt.Color;

import javax.swing.JTextField;

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


// ABSTRACT TEXT FIELD CLASS


public abstract class AbstractTextField
    extends JTextField
{

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

    private static final    Color   DEFAULT_INVALID_BACKGROUND_COLOUR   = new Color( 240, 192, 192 );

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

    protected AbstractTextField( )
    {
        invalidBackgroundColour = DEFAULT_INVALID_BACKGROUND_COLOUR;
    }

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

    protected AbstractTextField( int columns )
    {
        super( columns );
        invalidBackgroundColour = DEFAULT_INVALID_BACKGROUND_COLOUR;
    }

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

////////////////////////////////////////////////////////////////////////
//  Instance methods : overriding methods
////////////////////////////////////////////////////////////////////////

    public Color getBackground( )
    {
        return ( invalid ? invalidBackgroundColour
                         : (isEnabled( ) || (disabledBackgroundColour == null))
                                                                            ? super.getBackground( )
                                                                            : disabledBackgroundColour );
    }

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

    public void setText( String text )
    {
        invalid = false;
        super.setText( text );
    }

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

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

    public boolean isEmpty( )
    {
        try
        {
            return ( getText( ).length( ) == 0 );
        }
        catch ( NullPointerException e )
        {
            return true;
        }
    }

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

    public boolean isInvalid( )
    {
        return invalid;
    }

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

    public Color setDisabledBackgroundColour( )
    {
        return disabledBackgroundColour;
    }

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

    public Color getInvalidBackgroundColour( )
    {
        return invalidBackgroundColour;
    }

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

    public void setInvalid( boolean invalid )
    {
        if ( this.invalid != invalid )
        {
            this.invalid = invalid;
            repaint( );
        }
    }

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

    public void setDisabledBackgroundColour( Color colour )
    {
        if ( ((disabledBackgroundColour == null) && (colour != null)) ||
             ((disabledBackgroundColour != null) && !disabledBackgroundColour.equals( colour )) )
        {
            disabledBackgroundColour = colour;
            repaint( );
        }
    }

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

    public void setInvalidBackgroundColour( Color colour )
    {
        if ( !invalidBackgroundColour.equals( colour ) )
        {
            invalidBackgroundColour = colour;
            repaint( );
        }
    }

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

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

    private boolean invalid;
    private Color   disabledBackgroundColour;
    private Color   invalidBackgroundColour;

}

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