Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.g2d / src / org / simantics / g2d / dnd / DnDContext.java

diff --git a/bundles/org.simantics.g2d/src/org/simantics/g2d/dnd/DnDContext.java b/bundles/org.simantics.g2d/src/org/simantics/g2d/dnd/DnDContext.java
new file mode 100644 (file)
index 0000000..6a036cb
--- /dev/null
+++ b/bundles/org.simantics.g2d/src/org/simantics/g2d/dnd/DnDContext.java
@@ -0,0 +1,106 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+/*\r
+ *\r
+ * @author Toni Kalajainen\r
+ */\r
+package org.simantics.g2d.dnd;\r
+\r
+import java.awt.geom.Point2D;\r
+import java.util.ArrayList;\r
+import java.util.HashMap;\r
+import java.util.List;\r
+import java.util.Map;\r
+\r
+import org.simantics.utils.datastructures.context.Context;\r
+import org.simantics.utils.datastructures.hints.HintContext;\r
+import org.simantics.utils.datastructures.hints.IHintContext;\r
+\r
+/**\r
+ * Contains an ordered set of context items (see {@link #orderedItems}) which\r
+ * works around the fact that {@link Context} base implementation does not\r
+ * preserve any kind of order information for the added drag items, which is\r
+ * often useful for user experience's sake.\r
+ * \r
+ * <b>WARNING</b> DnDContext is not as thread-safe as its base implementation\r
+ * {@link Context}.\r
+ * \r
+ * @author Tuukka Lehtonen\r
+ */\r
+public class DnDContext extends Context<IDragItem> implements IDnDContext {\r
+\r
+    IHintContext            hintCtx       = new HintContext();\r
+\r
+    List<IDragItem>         orderedItems  = new ArrayList<IDragItem>();\r
+\r
+    Map<IDragItem, Point2D> itemPositions = new HashMap<IDragItem, Point2D>();\r
+\r
+    public DnDContext() {\r
+        super(IDragItem.class);\r
+    }\r
+\r
+    @Override\r
+    public IHintContext getHints() {\r
+        return hintCtx;\r
+    }\r
+\r
+    @Override\r
+    public synchronized void setItemPosition(IDragItem item, Point2D pos) {\r
+        if (item == null)\r
+            throw new NullPointerException("trying to set position " + pos + " for null IDragItem");\r
+        if (pos == null)\r
+            throw new NullPointerException("trying to set null position for dragged item " + item);\r
+        itemPositions.put(item, pos);\r
+    }\r
+\r
+    @Override\r
+    public synchronized Point2D getItemPosition(IDragItem item) {\r
+        return itemPositions.get(item);\r
+    }\r
+\r
+    @Override\r
+    public void add(IDragItem item) {\r
+        assertNotDisposed();\r
+        orderedItems.add(item);\r
+        boolean added = false;\r
+        try {\r
+            super.add(item);\r
+            added = true;\r
+        } finally {\r
+            if (!added)\r
+                orderedItems.remove(item);\r
+        }\r
+    }\r
+\r
+    @Override\r
+    public boolean remove(IDragItem item) {\r
+        assertNotDisposed();\r
+        boolean existed = super.remove(item);\r
+        if (existed)\r
+            orderedItems.remove(item);\r
+        return existed;\r
+    }\r
+\r
+    @Override\r
+    public void clear() {\r
+        assertNotDisposed();\r
+        orderedItems.clear();\r
+        super.clear();\r
+    }\r
+\r
+    @Override\r
+    public IDragItem[] toArray() {\r
+        assertNotDisposed();\r
+        return orderedItems.toArray(new IDragItem[orderedItems.size()]);\r
+    }\r
+\r
+}\r