ATM Simulation Implementation - Question Dialog Box

/*
 * Example ATM simulation - file QuestionDialog.java
 *
 * This file implements the a pop-up dialog that is utilized by the GUI for
 * some of the ATM components.  Since it is only utilized by classes in package
 * atmparts, it is not made public.
 *
 * This version has been modified to work correctly under JDK 1.1 (though it still
 * uses the 1.0.2 event model)
 *
 * Copyright (c) 1997, 1999 - Russell C. Bjork
 *
 */

package atm.atmparts;
import java.awt.*;

//

Class QuestionDialog

class QuestionDialog extends Dialog
  {

    //

    public QuestionDialog(String question, Component caller)
      { super(GUILayout.getContainingFrame(), true);
        setLayout(new BorderLayout());
        add("North", new Label(question));
        _answer = new TextField("");
        add("Center", _answer);
        Panel buttonPanel = new Panel();
        _okay = new Button("OK");
        buttonPanel.add(_okay);
        add("South", buttonPanel);
        pack();

        // Center this box in the outermost container holding the caller.  If
        // GUILayout found a frame for us when it did the layout, use this;
        // otherwise follow parents from the caller until we get to one that
        // has a null parent.
        
        Component topLevel;
        if (GUILayout.getContainingFrame() != null)
            topLevel = GUILayout.getContainingFrame();
        else
          { topLevel = caller;
            while (topLevel.getParent() != null)
                topLevel = topLevel.getParent();
          }
        Point topLevelLocation = topLevel.location();
        Dimension topLevelSize = topLevel.size();
        Dimension dialogSize = size();
        int dialogX = topLevelLocation.x + 
                      (topLevelSize.width - dialogSize.width) / 2;
        int dialogY = topLevelLocation.y + 
                      (topLevelSize.height - dialogSize.height) / 2;
        if (dialogX < 0) dialogX = 0;
        if (dialogY < 0) dialogY = 0;
        move(dialogX, dialogY);    
      }
   
    //

    public String answer()
      {	_answer.requestFocus();
        // This pops up the box, and then blocks until it is disposed by the answer
      	// method below, which occurs when the user clicks the OK button or presses
      	// return in the answer field.  
      	show();
        return _answer.getText();
      }
    
    //

    public boolean action(Event e, Object arg)
      { if (e.target == _answer || e.target == _okay )
          { hide();
            dispose();
            return true;
          }
        else
            return false;
      }
      
    //

    private TextField _answer;
    private Button _okay;
  }

//