true.
+ *
+ * When used together with {@link DnDNodeModel}, children can be reordered
+ * by Drag and Drop.
+ *
+ * @author Martin Entlicher
+ * @since 1.25
+ */
+public interface ReorderableTreeModel extends TreeModel {
+
+ /**
+ * Provide if this model implementation can reorder children nodes.
+ * @param parent The parent node of children that are test for reorder
+ * @return true if this model can handle reordering of children,
+ * false otherwise
+ * @throws UnknownTypeException if this model implementation is not
+ * able to decide the reorder capability for given node type
+ */
+ public boolean canReorder(Object parent) throws UnknownTypeException;
+
+ /**
+ * Reorder children nodes with a given permutation.
+ * @param parent The parent node of children that are being reordered
+ * @param perm permutation with the length of current child nodes. The permutation
+ * lists the new positions of the original nodes, that is, for nodes
+ * [A,B,C,D] and permutation [0,3,1,2], the final
+ * order would be [A,C,D,B].
+ * @throws IllegalArgumentException if the permutation is not valid
+ * @throws UnknownTypeException if this model implementation is not
+ * able to perform the reorder for given node type
+ */
+ public void reorder(Object parent, int[] perm) throws UnknownTypeException;
+
+}
diff --git a/spi.viewmodel/src/org/netbeans/spi/viewmodel/ReorderableTreeModelFilter.java b/spi.viewmodel/src/org/netbeans/spi/viewmodel/ReorderableTreeModelFilter.java
new file mode 100644
--- /dev/null
+++ b/spi.viewmodel/src/org/netbeans/spi/viewmodel/ReorderableTreeModelFilter.java
@@ -0,0 +1,78 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
+ *
+ * The contents of this file are subject to the terms of either the GNU
+ * General Public License Version 2 only ("GPL") or the Common
+ * Development and Distribution License("CDDL") (collectively, the
+ * "License"). You may not use this file except in compliance with the
+ * License. You can obtain a copy of the License at
+ * http://www.netbeans.org/cddl-gplv2.html
+ * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
+ * specific language governing permissions and limitations under the
+ * License. When distributing the software, include this License Header
+ * Notice in each file and include the License file at
+ * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the GPL Version 2 section of the License file that
+ * accompanied this code. If applicable, add the following below the
+ * License Header, with the fields enclosed by brackets [] replaced by
+ * your own identifying information:
+ * "Portions Copyrighted [year] [name of copyright owner]"
+ *
+ * If you wish your version of this file to be governed by only the CDDL
+ * or only the GPL Version 2, indicate your decision by adding
+ * "[Contributor] elects to include this software in this distribution
+ * under the [CDDL or GPL Version 2] license." If you do not indicate a
+ * single choice of license, a recipient has the option to distribute
+ * your version of this file under either the CDDL, the GPL Version 2 or
+ * to extend the choice of license to its licensees as provided above.
+ * However, if you add GPL Version 2 code and therefore, elected the GPL
+ * Version 2 license, then the option applies only if the new code is
+ * made subject to such option by the copyright holder.
+ *
+ * Contributor(s):
+ *
+ * Portions Copyrighted 2009 Sun Microsystems, Inc.
+ */
+
+package org.netbeans.spi.viewmodel;
+
+/**
+ * Filters an original tree data model that supports reordering
+ * of child nodes. The created {@link org.openide.nodes.Children} will
+ * implement {@link org.openide.nodes.Index} if
+ * {@link #canReorder(org.netbeans.spi.viewmodel.ReorderableTreeModel, java.lang.Object)}
+ * returns true.
+ *
+ * @author Martin Entlicher
+ * @since 1.25
+ */
+public interface ReorderableTreeModelFilter extends TreeModelFilter {
+
+ /**
+ * Provide if this filter implementation can reorder children nodes.
+ * @param original The original ReorderableTreeModel
+ * @param parent The parent node of children that are test for reorder
+ * @return true if this model can handle reordering of children,
+ * false otherwise
+ * @throws UnknownTypeException if this model implementation is not
+ * able to decide the reorder capability for given node type
+ */
+ public boolean canReorder(ReorderableTreeModel original, Object parent) throws UnknownTypeException;
+
+ /**
+ * Reorder children nodes with a given permutation.
+ * @param parent The parent node of children that are being reordered
+ * @param perm permutation with the length of current child nodes. The permutation
+ * lists the new positions of the original nodes, that is, for nodes
+ * [A,B,C,D] and permutation [0,3,1,2], the final
+ * order would be [A,C,D,B].
+ * @throws IllegalArgumentException if the permutation is not valid
+ * @throws UnknownTypeException if this model implementation is not
+ * able to perform the reorder for given node type
+ */
+ public void reorder(ReorderableTreeModel original, Object parent, int[] perm) throws UnknownTypeException;
+
+}
diff --git a/spi.viewmodel/test/unit/src/org/netbeans/modules/viewmodel/ReorderableTreeModelTest.java b/spi.viewmodel/test/unit/src/org/netbeans/modules/viewmodel/ReorderableTreeModelTest.java
new file mode 100644
--- /dev/null
+++ b/spi.viewmodel/test/unit/src/org/netbeans/modules/viewmodel/ReorderableTreeModelTest.java
@@ -0,0 +1,199 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
+ *
+ * The contents of this file are subject to the terms of either the GNU
+ * General Public License Version 2 only ("GPL") or the Common
+ * Development and Distribution License("CDDL") (collectively, the
+ * "License"). You may not use this file except in compliance with the
+ * License. You can obtain a copy of the License at
+ * http://www.netbeans.org/cddl-gplv2.html
+ * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
+ * specific language governing permissions and limitations under the
+ * License. When distributing the software, include this License Header
+ * Notice in each file and include the License file at
+ * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the GPL Version 2 section of the License file that
+ * accompanied this code. If applicable, add the following below the
+ * License Header, with the fields enclosed by brackets [] replaced by
+ * your own identifying information:
+ * "Portions Copyrighted [year] [name of copyright owner]"
+ *
+ * If you wish your version of this file to be governed by only the CDDL
+ * or only the GPL Version 2, indicate your decision by adding
+ * "[Contributor] elects to include this software in this distribution
+ * under the [CDDL or GPL Version 2] license." If you do not indicate a
+ * single choice of license, a recipient has the option to distribute
+ * your version of this file under either the CDDL, the GPL Version 2 or
+ * to extend the choice of license to its licensees as provided above.
+ * However, if you add GPL Version 2 code and therefore, elected the GPL
+ * Version 2 license, then the option applies only if the new code is
+ * made subject to such option by the copyright holder.
+ *
+ * Contributor(s):
+ *
+ * Portions Copyrighted 2009 Sun Microsystems, Inc.
+ */
+
+package org.netbeans.modules.viewmodel;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import org.netbeans.junit.NbTestCase;
+import org.netbeans.spi.viewmodel.Model;
+import org.netbeans.spi.viewmodel.ModelEvent;
+import org.netbeans.spi.viewmodel.ModelListener;
+import org.netbeans.spi.viewmodel.Models;
+import org.netbeans.spi.viewmodel.NodeModel;
+import org.netbeans.spi.viewmodel.ReorderableTreeModel;
+import org.netbeans.spi.viewmodel.TreeModel;
+import org.netbeans.spi.viewmodel.UnknownTypeException;
+import org.openide.nodes.Index;
+import org.openide.nodes.Node;
+import org.openide.util.RequestProcessor;
+
+/**
+ * Tests that reorderable model produces node with Index implementation
+ *
+ * @author Martin Entlicher
+ */
+public class ReorderableTreeModelTest extends NbTestCase {
+
+ private Node root;
+
+ public ReorderableTreeModelTest (String s) {
+ super (s);
+ }
+
+ private void setUpModel() {
+ Model m = new ReorderableModelImpl();
+
+ ArrayList l = new ArrayList ();
+ l.add(m);
+ Models.CompoundModel mcm = Models.createCompoundModel(l);
+ OutlineTable tt = BasicTest.createView(mcm);
+
+ RequestProcessor rp = tt.currentTreeModelRoot.getRootNode().getRequestProcessor();
+ BasicTest.waitFinished (rp);
+
+ root = tt.getExplorerManager ().getRootContext ();
+ }
+
+ public void testChildrenReorder() {
+ setUpModel();
+
+ Index indexImpl = root.getLookup().lookup(Index.class);
+ assertNull("Root must not provide Index, root is not reordeable!", indexImpl);
+
+ Node[] ch1 = root.getChildren().getNodes();
+ assertEquals(2, ch1.length);
+
+ indexImpl = ch1[1].getLookup().lookup(Index.class);
+ assertNull(ch1[1]+ " must not provide Index, it is not reordeable!", indexImpl);
+ indexImpl = ch1[0].getLookup().lookup(Index.class);
+ assertNotNull(ch1[0]+ " must provide Index, it is reordeable!", indexImpl);
+
+ indexImpl.reorder(new int[] { 2, 0, 1, 4, 3 });
+ // => "3", "1", "2", "5", "4"
+ String[] reorderedNames = new String[] { "2", "3", "1", "5", "4" };
+ Node[] reorderedNodes = ch1[0].getChildren().getNodes();
+ assertEquals(reorderedNames.length, reorderedNodes.length);
+ String nodes = "Nodes = "+Arrays.toString(reorderedNodes);
+ for (int i = 0; i < reorderedNodes.length; i++) {
+ assertEquals(nodes, reorderedNames[i], reorderedNodes[i].getDisplayName());
+ }
+ }
+
+ private static final class ReorderableModelImpl implements ReorderableTreeModel, NodeModel {
+
+ private static final String CAN_REORDER = "canReorder";
+ private static final String CAN_NOT_REORDER = "canNotReorder";
+
+ private final String[] childrenReordered = new String[] { "1", "2", "3", "4", "5" };
+
+ public boolean canReorder(Object parent) throws UnknownTypeException {
+ return /*ROOT == parent ||*/ CAN_REORDER.equals(parent);
+ }
+
+ public void reorder(Object parent, int[] perm) throws UnknownTypeException {
+ //System.err.println("reorder("+parent+", "+Arrays.toString(perm)+")");
+ //Thread.dumpStack();
+ if (!(/*ROOT == parent ||*/ CAN_REORDER.equals(parent))) {
+ throw new IllegalStateException("reorder called on "+parent);
+ }
+ if (perm.length != childrenReordered.length) {
+ throw new IllegalArgumentException("Permutation of length "+perm.length+", but have "+childrenReordered.length+" children.");
+ }
+ checkPermutation(perm);
+ String[] ch = childrenReordered.clone();
+ for (int i = 0; i < ch.length; i++) {
+ //System.err.println("ch["+perm[i]+"] = "+ch[i]);
+ childrenReordered[perm[i]] = ch[i];
+ }
+ }
+
+ private static void checkPermutation(int[] permutation) throws IllegalArgumentException {
+ int max = permutation.length;
+ int[] check = new int[max];
+ for (int i = 0; i < max; i++) {
+ int p = permutation[i];
+ if (p >= max) {
+ throw new IllegalArgumentException("Permutation "+Arrays.toString(permutation)+" is not a valid permutation, it contains element "+p+", which is bigger than the length of the permutation.");
+ }
+ if (p < 0) {
+ throw new IllegalArgumentException("Permutation "+Arrays.toString(permutation)+" is not a valid permutation, it contains element "+p+", which is negative.");
+ }
+ if (check[p] != 0) {
+ throw new IllegalArgumentException("Permutation "+Arrays.toString(permutation)+" is not a valid permutation, it contains element "+p+" twice or more times.");
+ }
+ check[p] = 1;
+ }
+ }
+
+ public Object getRoot() {
+ return ROOT;
+ }
+
+ public Object[] getChildren(Object parent, int from, int to) throws UnknownTypeException {
+ if (ROOT == parent) {
+ return new String[] { CAN_REORDER, CAN_NOT_REORDER };
+ } else if (CAN_REORDER.equals(parent)) {
+ return childrenReordered;
+ } else if (CAN_NOT_REORDER.equals(parent)) {
+ return new String[] { "a", "b", "c", "d", "e" };
+ } else {
+ return new Object[] {};
+ }
+ }
+
+ public boolean isLeaf(Object node) throws UnknownTypeException {
+ return ((String) node).length() == 1;
+ }
+
+ public int getChildrenCount(Object node) throws UnknownTypeException {
+ return Integer.MAX_VALUE;
+ }
+
+ public void addModelListener(ModelListener l) {
+ }
+
+ public void removeModelListener(ModelListener l) {
+ }
+
+ public String getDisplayName(Object node) throws UnknownTypeException {
+ return (String) node;
+ }
+
+ public String getIconBase(Object node) throws UnknownTypeException {
+ return null;
+ }
+
+ public String getShortDescription(Object node) throws UnknownTypeException {
+ return node+" of "+getClass().getSimpleName();
+ }
+
+ }
+
+}