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

diff --git a/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDragAdapter.java b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDragAdapter.java
new file mode 100644
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+++ b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/DelegatingDragAdapter.java
@@ -0,0 +1,115 @@
+/*******************************************************************************
+ * 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 java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.eclipse.swt.dnd.DragSource;
+import org.eclipse.swt.dnd.DragSourceEvent;
+import org.eclipse.swt.dnd.DragSourceListener;
+import org.eclipse.swt.dnd.Transfer;
+import org.eclipse.swt.dnd.TransferData;
+
+import org.eclipse.jface.util.Assert;
+
+/**
+ * A delegating drag adapter negotiates between a set of <code>TransferDragSourceListener</code>s
+ * On <code>dragStart</code> the adapter determines the listener to be used for any further
+ * <code>drag*</code> callback.
+ */
+public class DelegatingDragAdapter implements DragSourceListener {
+
+	private TransferDragSourceListener[] fPossibleListeners;
+	private List fActiveListeners;
+	private TransferDragSourceListener fFinishListener;
+	
+	public DelegatingDragAdapter(TransferDragSourceListener[] listeners) {
+		setPossibleListeners(listeners);
+	}
+	
+	protected void setPossibleListeners(TransferDragSourceListener[] listeners) {
+		Assert.isNotNull(listeners);
+		Assert.isTrue(fActiveListeners == null, "Can only set possible listeners before drag operation has started"); //$NON-NLS-1$
+		fPossibleListeners= listeners;
+	}
+	
+	/* non Java-doc
+	 * @see DragSourceListener
+	 */
+	public void dragStart(DragSourceEvent event) {
+		fFinishListener= null;
+		boolean saveDoit= event.doit;
+		Object saveData= event.data;
+		boolean doIt= false;
+		List transfers= new ArrayList(fPossibleListeners.length);
+		fActiveListeners= new ArrayList(fPossibleListeners.length);
+		
+		for (int i= 0; i < fPossibleListeners.length; i++) {
+			TransferDragSourceListener listener= fPossibleListeners[i];
+			event.doit= saveDoit;
+			listener.dragStart(event);
+			if (event.doit) {
+				transfers.add(listener.getTransfer());
+				fActiveListeners.add(listener);
+			}
+			doIt= doIt || event.doit;
+		}
+		if (doIt) {
+			((DragSource)event.widget).setTransfer((Transfer[])transfers.toArray(new Transfer[transfers.size()]));
+		}
+		event.data= saveData;
+		event.doit= doIt;
+	}
+
+	/* non Java-doc
+	 * @see DragSourceListener
+	 */
+	public void dragSetData(DragSourceEvent event) {
+		fFinishListener= getListener(event.dataType);
+		if (fFinishListener != null)
+			fFinishListener.dragSetData(event);
+	}
+	
+	/* non Java-doc
+	 * @see DragSourceListener
+	 */
+	public void dragFinished(DragSourceEvent event) {
+		try{
+			if (fFinishListener != null) {
+				fFinishListener.dragFinished(event);
+			} else {
+				// If the user presses Escape then we get a dragFinished without
+				// getting a dragSetData before.
+				fFinishListener= getListener(event.dataType);
+				if (fFinishListener != null)
+					fFinishListener.dragFinished(event);
+			}
+		} finally{
+			fFinishListener= null;
+			fActiveListeners= null;
+		}	
+	}
+	
+	private TransferDragSourceListener getListener(TransferData type) {
+		if (type == null)
+			return null;
+			
+		for (Iterator iter= fActiveListeners.iterator(); iter.hasNext();) {
+			TransferDragSourceListener listener= (TransferDragSourceListener)iter.next();
+			if (listener.getTransfer().isSupportedType(type)) {
+				return listener;
+			}
+		}
+		return null;
+	}	
+}