Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/resources/workbench/ResourceDropAction.java
if (this.alwaysOverwrite)
			return ALL;
		final String returnCode[] = {CANCEL};
		final String msg = ResourceNavigatorMessages.format("DropAdapter.overwriteQuery", new Object[]{pathString}); 
		final String[] options = {IDialogConstants.YES_LABEL, IDialogConstants.YES_TO_ALL_LABEL, IDialogConstants.NO_LABEL, IDialogConstants.CANCEL_LABEL};
		getDisplay().syncExec(new Runnable() {
			public void run() {
				MessageDialog dialog = new MessageDialog(getShell(), ResourceNavigatorMessages.getString("DropAdapter.question"), null, msg, MessageDialog.QUESTION, options, 0); 
				dialog.open();
				int returnVal = dialog.getReturnCode();
				String[] returnCodes = {YES, ALL, NO, CANCEL};
				returnCode[0] = returnVal < 0 ? CANCEL : returnCodes[returnVal];
			}
		});
		if (returnCode[0] == ALL)
			this.alwaysOverwrite = true;
		return returnCode[0];
	}
 
	/**
	 * @return
	 */
	private Display getDisplay() {
		
		return null;
	}
	public boolean validateDrop(PluginDropAdapter dropAdapter, Object target, int operation, TransferData transferType) {
		return validateTarget(dropAdapter, target, transferType).isOK();
	}
	public boolean run(PluginDropAdapter dropAdapter, Object data, Object target) {