--- /dev/null
+/*******************************************************************************
+ * 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;
+
+//incastrix
+//import org.eclipse.jface.text.Assert;
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.jface.viewers.StructuredViewer;
+import org.eclipse.swt.dnd.DND;
+import org.eclipse.swt.dnd.DropTargetEvent;
+import org.eclipse.swt.dnd.DropTargetListener;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.swt.graphics.Rectangle;
+import org.eclipse.swt.widgets.Item;
+import org.eclipse.swt.widgets.TableItem;
+import org.eclipse.swt.widgets.TreeItem;
+
+/**
+ * A drag and drop adapter to be used together with structured viewers. The
+ * adapater delegates the <code>dragEnter</code>, <code>dragOperationChanged
+ * </code>,
+ * <code>dragOver</code> and <code>dropAccept</code> method to the
+ * <code>validateDrop</code> method. Furthermore it adds location feedback.
+ */
+public class JdtViewerDropAdapter implements DropTargetListener {
+
+ /**
+ * Constant describing the position of the mouse cursor relative to the
+ * target object. This means the mouse is positioned slightly before the
+ * target.
+ */
+ protected static final int LOCATION_BEFORE = 1;
+
+ /**
+ * Constant describing the position of the mouse cursor relative to the
+ * target object. This means the mouse is positioned slightly after the
+ * target.
+ */
+ protected static final int LOCATION_AFTER = 2;
+
+ /**
+ * Constant describing the position of the mouse cursor relative to the
+ * target object. This means the mouse is positioned directly on the target.
+ */
+ protected static final int LOCATION_ON = 3;
+
+ /**
+ * Constant describing the position of the mouse cursor relative to the
+ * target object. This means the mouse is not positioned over or near any
+ * valid target.
+ */
+ protected static final int LOCATION_NONE = 4;
+
+ /**
+ * The threshold used to determine if the mouse is before or after an item.
+ */
+ private static final int LOCATION_EPSILON = 5;
+
+ /**
+ * Style to enable location feedback.
+ */
+ public static final int INSERTION_FEEDBACK = 1 << 1;
+
+ private StructuredViewer fViewer;
+
+ private int fFeedback;
+
+ private boolean fShowInsertionFeedback;
+
+ private int fRequestedOperation;
+
+ private int fLastOperation;
+
+ protected int fLocation;
+
+ protected Object fTarget;
+
+ public JdtViewerDropAdapter(StructuredViewer viewer, int feedback) {
+ fViewer = viewer;
+ Assert.isNotNull(fViewer);
+ fFeedback = feedback;
+ fLastOperation = -1;
+ }
+
+ /**
+ * Controls whether the drop adapter shows insertion feedback or not.
+ *
+ * @param showInsertionFeedback
+ * <code>true</code> if the drop adapter is supposed to show
+ * insertion feedback. Otherwise <code>false</code>
+ */
+// public void showInsertionFeedback(boolean showInsertionFeedback) {
+// fShowInsertionFeedback = showInsertionFeedback;
+// }
+
+ /**
+ * Returns the viewer this adapter is working on.
+ */
+// protected StructuredViewer getViewer() {
+// return fViewer;
+// }
+
+ // ---- Hooks to override
+ // -----------------------------------------------------
+
+ /**
+ * The actual drop has occurred. Calls
+ * <code>drop(Object target, DropTargetEvent event)
+ * </code>.
+ *
+ * @see DropTargetListener#drop(org.eclipse.swt.dnd.DropTargetEvent)
+ */
+ public void drop(DropTargetEvent event) {
+ drop(fTarget, event);
+ }
+
+ /**
+ * The actual drop has occurred.
+ *
+ * @param target
+ * the drop target in form of a domain element.
+ * @param event
+ * the drop traget event
+ */
+ public void drop(Object target, DropTargetEvent event) {
+ }
+
+ /**
+ * Checks if the drop is valid. The method calls <code>validateDrop
+ * (Object target, DropTargetEvent event). Implementors can alter the
+ * <code>currentDataType</code> field and the <code>detail</code> field
+ * to give feedback about drop acceptence.
+ */
+ public void validateDrop(DropTargetEvent event) {
+ validateDrop(fTarget, event, fRequestedOperation);
+ }
+
+ /**
+ * Checks if the drop on the current target is valid. The method can alter
+ * the <code>currentDataType</code> field and the <code>
+ * detail</code>
+ * field to give feedback about drop acceptence.
+ *
+ * @param target
+ * the drop target in form of a domain element.
+ * @param event
+ * the drop traget event
+ * @param operation
+ * the operation requested by the user.
+ */
+ public void validateDrop(Object target, DropTargetEvent event, int operation) {
+ }
+
+ public void dragEnter(DropTargetEvent event) {
+ dragOperationChanged(event);
+ }
+
+ public void dragLeave(DropTargetEvent event) {
+ fTarget = null;
+ fLocation = LOCATION_NONE;
+ }
+
+ public void dragOperationChanged(DropTargetEvent event) {
+ fRequestedOperation = event.detail;
+ fTarget = computeTarget(event);
+ fLocation = computeLocation(event);
+ validateDrop(event);
+ fLastOperation = event.detail;
+ computeFeedback(event);
+ }
+
+ public void dragOver(DropTargetEvent event) {
+ Object oldTarget = fTarget;
+ fTarget = computeTarget(event);
+
+ // set the location feedback
+ int oldLocation = fLocation;
+ fLocation = computeLocation(event);
+ if (oldLocation != fLocation || oldTarget != fTarget
+ || fLastOperation != event.detail) {
+ validateDrop(event);
+ fLastOperation = event.detail;
+ } else {
+ event.detail = fLastOperation;
+ }
+ computeFeedback(event);
+ }
+
+ public void dropAccept(DropTargetEvent event) {
+ fTarget = computeTarget(event);
+ validateDrop(event);
+ fLastOperation = event.detail;
+ }
+
+ /**
+ * Returns the data held by <code>event.item</code>. Inside a viewer this
+ * corresponds to the items data model element.
+ */
+ protected Object computeTarget(DropTargetEvent event) {
+ return event.item == null ? null : event.item.getData();
+ }
+
+ /**
+ * Returns the position of the given coordinates relative to the given
+ * target. The position is determined to be before, after, or on the item,
+ * based on some threshold value. The return value is one of the LOCATION_*
+ * constants defined in this class.
+ */
+ final protected int computeLocation(DropTargetEvent event) {
+ if (!(event.item instanceof Item))
+ return LOCATION_NONE;
+
+ Item item = (Item) event.item;
+ Point coordinates = fViewer.getControl().toControl(
+ new Point(event.x, event.y));
+ Rectangle bounds = getBounds(item);
+ if (bounds == null) {
+ return LOCATION_NONE;
+ }
+ if ((coordinates.y - bounds.y) < LOCATION_EPSILON) {
+ return LOCATION_BEFORE;
+ }
+ if ((bounds.y + bounds.height - coordinates.y) < LOCATION_EPSILON) {
+ return LOCATION_AFTER;
+ }
+ return LOCATION_ON;
+ }
+
+ /**
+ * Returns the bounds of the given item, or <code>null</code> if it is not
+ * a valid type of item.
+ */
+ private Rectangle getBounds(Item item) {
+ if (item instanceof TreeItem)
+ return ((TreeItem) item).getBounds();
+
+ if (item instanceof TableItem)
+ return ((TableItem) item).getBounds(0);
+
+ return null;
+ }
+
+ /**
+ * Sets the drag under feedback corresponding to the value of
+ * <code>fLocation</code> and the <code>INSERTION_FEEDBACK</code> style
+ * bit.
+ */
+ protected void computeFeedback(DropTargetEvent event) {
+ if (!fShowInsertionFeedback && fLocation != LOCATION_NONE) {
+ event.feedback = DND.FEEDBACK_SELECT;
+ } else {
+ if (fLocation == LOCATION_BEFORE) {
+ event.feedback = DND.FEEDBACK_INSERT_BEFORE;
+ } else if (fLocation == LOCATION_AFTER) {
+ event.feedback = DND.FEEDBACK_INSERT_AFTER;
+ }
+ }
+ event.feedback |= fFeedback;
+ }
+
+ /**
+ * Sets the drop operation to </code>DROP_NODE<code>.
+ */
+ protected void clearDropOperation(DropTargetEvent event) {
+ event.detail = DND.DROP_NONE;
+ }
+
+ /**
+ * Returns the requested drop operation.
+ */
+ protected int getRequestedOperation() {
+ return fRequestedOperation;
+ }
+}
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