com.ibm.as400.vaccess.DialogCache Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jt400 Show documentation
The Open Source version of the IBM Toolbox for Java
The newest version!
///////////////////////////////////////////////////////////////////////////////
//                                                                             
// JTOpen (IBM Toolbox for Java - OSS version)                              
//                                                                             
// Filename: DialogCache.java
//                                                                             
// The source code contained herein is licensed under the IBM Public License   
// Version 1.0, which has been approved by the Open Source Initiative.         
// Copyright (C) 1997-2000 International Business Machines Corporation and     
// others. All rights reserved.                                                
//                                                                             
///////////////////////////////////////////////////////////////////////////////

package com.ibm.as400.vaccess;
  
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.Hashtable;
import javax.swing.JDialog;


/**
The DialogCache class maintains a Hashtable of dialogs, each
associated with a particular target object.  This object can
help a GUI reuse dialogs, so that at most one GUI will appear,
even if the end-user selects the same target multiple times.
**/
class DialogCache
{
  private static final String copyright = "Copyright (C) 1997-2000 International Business Machines Corporation and others.";




    // Private data.
    private static Hashtable    dialogTable_    = new Hashtable();



/**
Resolves the dialog for a particular target object.

@param target   The target object.
@return         The dialog, or null if there is none.
**/
    public JDialog resolveDialog(Object target)
    {
        synchronized(dialogTable_) {

            // If there is already a dialog for this resource,
            // the use it.
            if (dialogTable_.containsKey(target)) {               
                JDialog dialog = (JDialog)dialogTable_.get(target);
                dialog.toFront();
                dialog.requestFocus();
                return dialog;
            }

            else
                return null;
        }
    }



/**
Adds a new dialog to the cache.

@param target   The target object.
@param dialog   The dialog.
**/
    public void addDialog(Object target, JDialog dialog)
    {
        synchronized(dialogTable_) {
            // Add a listener to the dialog, so that when it closes,
            // it will remove itself from the cache.
            dialog.addWindowListener(new WindowListener_(target));

            // Add the new one to our table and return it.
            dialogTable_.put(target, dialog);
        }
    }



/**
Removes dialogs from the cache when they are closed.
**/
    private class WindowListener_ extends WindowAdapter
    {
        private Object target_;

        public WindowListener_(Object target)
        {
            target_ = target;
        }

        public void windowClosing(WindowEvent event)
        {
            synchronized(dialogTable_) {
                if (dialogTable_.containsKey(target_))
                    dialogTable_.remove(target_);
            }
        }

        public void windowClosed(WindowEvent event)
        {
            synchronized(dialogTable_) {
                if (dialogTable_.containsKey(target_))
                    dialogTable_.remove(target_);
            }
        }
    }


}