001    // Copyright 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.tree;
016    
017    import org.apache.tapestry5.BaseOptimizedSessionPersistedObject;
018    import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
019    
020    import java.util.Set;
021    
022    /**
023     * Default implementation of {@link TreeSelectionModel}. This is simply a wrapper around a set of node ids.
024     *
025     * @param <T> type of node
026     */
027    public class DefaultTreeSelectionModel<T> extends BaseOptimizedSessionPersistedObject implements TreeSelectionModel<T>
028    {
029        private final Set<String> selectedIds = CollectionFactory.newSet();
030    
031        public boolean isSelected(TreeNode<T> node)
032        {
033            assert node != null;
034    
035            return selectedIds.contains(node.getId());
036        }
037    
038        public void select(TreeNode<T> node)
039        {
040            assert node != null;
041    
042            if (selectedIds.add(node.getId()))
043                markDirty();
044        }
045    
046        public void unselect(TreeNode<T> node)
047        {
048            assert node != null;
049    
050            if (selectedIds.remove(node.getId()))
051                markDirty();
052        }
053    
054        public void clear()
055        {
056            if (!selectedIds.isEmpty())
057            {
058                selectedIds.clear();
059                markDirty();
060            }
061        }
062    }