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WebLaf is a Java Swing Look and Feel and extended components library for cross-platform applications
/*
* This file is part of WebLookAndFeel library.
*
* WebLookAndFeel library 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.
*
* WebLookAndFeel library 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 WebLookAndFeel library. If not, see viewHandlers;
/**
* Whether or not something is being dragged right now.
*/
private static boolean dragging = false;
/**
* Dragged object representation variables.
*/
private static WebGlassPane glassPane;
private static Object data;
private static BufferedImage view;
private static Component dropLocation;
private static DragViewHandler dragViewHandler;
/**
* Whether manager is initialized or not.
*/
private static boolean initialized = false;
/**
* Initializes manager if it wasn't already initialized.
*/
public static synchronized void initialize ()
{
// To avoid more than one initialization
if ( !initialized )
{
// Remember that initialization happened
initialized = true;
// View handlers map
viewHandlers = new HashMap ();
final DragSourceAdapter dsa = new DragSourceAdapter ()
{
@Override
public void dragEnter ( final DragSourceDragEvent dsde )
{
dragEnterImpl ( dsde );
}
/**
* Performs actions on drag enter.
*
* @param dsde drag source drag event
*/
protected void dragEnterImpl ( final DragSourceDragEvent dsde )
{
// todo Do not recreate view few times while dragging
// Save drop location component
final DragSourceContext dsc = dsde.getDragSourceContext ();
dropLocation = dsc.getComponent ();
// Deciding on enter what to display for this kind of data
final Transferable transferable = dsc.getTransferable ();
final DataFlavor[] flavors = transferable.getTransferDataFlavors ();
for ( final DataFlavor flavor : flavors )
{
if ( viewHandlers.containsKey ( flavor ) )
{
try
{
data = transferable.getTransferData ( flavor );
dragViewHandler = viewHandlers.get ( flavor );
view = dragViewHandler.getView ( data, dsde );
glassPane = GlassPaneManager.getGlassPane ( dsc.getComponent () );
glassPane.setPaintedImage ( view, getLocation ( glassPane, dsde ) );
break;
}
catch ( final Throwable e )
{
Log.error ( DragManager.class, e );
}
}
}
// Marking drag operation
dragging = true;
}
@Override
public void dragMouseMoved ( final DragSourceDragEvent dsde )
{
final DragSourceContext dsc = dsde.getDragSourceContext ();
if ( dsc.getComponent () != dropLocation )
{
dragEnterImpl ( dsde );
}
// Move displayed data
if ( view != null )
{
final WebGlassPane gp = GlassPaneManager.getGlassPane ( dsde.getDragSourceContext ().getComponent () );
if ( gp != glassPane )
{
glassPane.clearPaintedImage ();
glassPane = gp;
}
glassPane.setPaintedImage ( view, getLocation ( glassPane, dsde ) );
}
}
/**
* Returns preferred dragged element location on glass pane.
*
* @param gp glass pane
* @param dsde drag source drag event
* @return preferred dragged element location on glass pane
*/
public Point getLocation ( final WebGlassPane gp, final DragSourceDragEvent dsde )
{
final Point mp = SwingUtils.getMousePoint ( gp );
final Point vp = dragViewHandler.getViewRelativeLocation ( data, dsde );
return new Point ( mp.x + vp.x, mp.y + vp.y );
}
@Override
public void dragDropEnd ( final DragSourceDropEvent dsde )
{
// Marking drag operation
dragging = false;
// Cleanup drop location component
dropLocation = null;
// Cleanup displayed data
if ( view != null )
{
dragViewHandler.dragEnded ( data, dsde );
glassPane.clearPaintedImage ();
glassPane = null;
data = null;
view = null;
dragViewHandler = null;
}
}
};
DragSource.getDefaultDragSource ().addDragSourceListener ( dsa );
DragSource.getDefaultDragSource ().addDragSourceMotionListener ( dsa );
}
}
/**
* Returns whether or not something is being dragged right now within the application.
*
* @return true if something is being dragged right now within the application, false otherwise
*/
public static boolean isDragging ()
{
return dragging;
}
/**
* Registers new DragViewHandler.
*
* @param dragViewHandler DragViewHandler to register
*/
public static void registerViewHandler ( final DragViewHandler dragViewHandler )
{
viewHandlers.put ( dragViewHandler.getObjectFlavor (), dragViewHandler );
}
/**
* Unregisters new DragViewHandler.
*
* @param dragViewHandler DragViewHandler to unregister
*/
public static void unregisterViewHandler ( final DragViewHandler dragViewHandler )
{
viewHandlers.remove ( dragViewHandler.getObjectFlavor () );
}
}