X-Git-Url: http://secure.phpeclipse.com

diff --git a/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDropAdapter.java b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDropAdapter.java
new file mode 100644
index 0000000..c3ad84a
--- /dev/null
+++ b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDropAdapter.java
@@ -0,0 +1,109 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package net.sourceforge.phpdt.internal.ui.dnd;
+
+import org.eclipse.swt.dnd.DropTargetEvent;
+import org.eclipse.swt.dnd.DropTargetListener;
+import org.eclipse.swt.dnd.TransferData;
+
+import org.eclipse.jface.util.Assert;
+
+/**
+ * A delegating drop adapter negotiates between a set of <code>TransferDropTargetListener</code>s
+ * On <code>dragEnter</code> the adapter determines the listener to be used for any further
+ * <code>drag*</code> callback.
+ */
+public class DelegatingDropAdapter implements DropTargetListener {
+
+	private TransferDropTargetListener[] fListeners;
+	
+	private TransferDropTargetListener fChosenListener;
+
+	/**
+	 * Creates a new delegating drop adapter.
+	 * 
+	 * @param listeners an array of potential listeners
+	 */	
+	public DelegatingDropAdapter(TransferDropTargetListener[] listeners) {
+		fListeners= listeners;
+		Assert.isNotNull(listeners);
+	}
+
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void dragEnter(DropTargetEvent event) {
+		fChosenListener= null;
+		event.currentDataType= selectPreferredListener(event.dataTypes);
+		if (fChosenListener != null)
+			fChosenListener.dragEnter(event);
+	}
+	
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void dragLeave(DropTargetEvent event){
+		if (fChosenListener != null)
+			fChosenListener.dragLeave(event);
+	}
+	
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void dragOperationChanged(DropTargetEvent event){
+		if (fChosenListener != null)
+			fChosenListener.dragOperationChanged(event);
+	}
+	
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void dragOver(DropTargetEvent event){
+		if (fChosenListener != null)
+			fChosenListener.dragOver(event);
+	}
+	
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void drop(DropTargetEvent event){
+		if (fChosenListener != null)
+			fChosenListener.drop(event);
+		fChosenListener= null;	
+	}
+	
+	/* non Java-doc
+	 * @see DropTargetListener
+	 */
+	public void dropAccept(DropTargetEvent event){
+		if (fChosenListener != null)
+			fChosenListener.dropAccept(event);
+	}
+	
+	private TransferData selectPreferredListener(TransferData[] dataTypes) {
+		for (int i= 0; i < fListeners.length; i++) {
+			TransferData data= computeTransferData(dataTypes, fListeners[i]);
+			if (data != null)
+				return data;
+		}
+		return null;
+	}
+	
+	private TransferData computeTransferData(TransferData[] dataTypes, TransferDropTargetListener listener) {
+		for (int i= 0; i < dataTypes.length; i++) {
+			if (listener.getTransfer().isSupportedType(dataTypes[i])) {
+				fChosenListener= listener;
+				return dataTypes[i];
+			}
+		}
+		return null;
+	}	
+}