/** @file
* Copyright (C) 2004–5 John D Lamb (J.D.Lamb@btinternet.com)
* Copyright (C) 20007 John D Lamb (J.D.Lamb@btinternet.com)
*
* 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.
*/
package jscicalc.button;
import jscicalc.CalculatorApplet;
import jscicalc.pobject.On;
import jscicalc.complex.Complex;
/**
* Button with two functions. One is to switch the calculator on, the other to
* clear the current expression (or the most recently evaluated since EqualsButton
* and its subclasses leave the expression visible). In fact both functions are
* always carried out because switching a calculator on when it is already on has
* no effect and when we sitch on we always want a clear display.
*
* @author J. D. Lamb
* @version $Revision: 1.4 $
*/
public class OnButton extends CalculatorButton {
/**
* Constructor. Sets PObject to On.
* @param applet The <em>controller</em> object.
*/
public OnButton( CalculatorApplet applet ){
this.applet = applet;
this.pobject = new On();
setText();
setTextSize();
tooltip = "switches the calculator on and clears the display";
shortcut = 'o';
setToolTipText();
addActionListener( this );
}
/**
* Ask CalculatorApplet to set its state to on and clear the DisplayLabel.
* @param actionEvent The event that generated this method call: usually a button
* press or called when CalculatorApplet responded to the key associated with
* this button
*/
public void actionPerformed( java.awt.event.ActionEvent actionEvent ){
synchronized( applet ){
if( getApplet().getMode() != 0 ){
getApplet().setMode( 0 );
getApplet().setShift( false );
}
getApplet().setOn( true );
getApplet().clear();
getApplet().setValue( new Complex( 0 ) );
getApplet().updateDisplay( true, true );
getApplet().requestFocusInWindow();
}
}
private static final long serialVersionUID = 1L;
}