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 java.util.List;
018    
019    import javax.swing.tree.TreeSelectionModel;
020    
021    import org.apache.tapestry5.ValueEncoder;
022    import org.apache.tapestry5.corelib.components.Tree;
023    
024    /**
025     * A model for tree-oriented data used by the {@link Tree} component. The default implemention, {@link DefaultTreeModel}
026     * uses a {@link ValueEncoder} and a {@link TreeModelAdapter} to supply the
027     * underlying information.
028     * 
029     * @param <T>
030     *            type of data in the tree
031     * @since 5.3
032     * @see TreeSelectionModel
033     */
034    public interface TreeModel<T>
035    {
036        /**
037         * Returns the node or nodes that are the top level of the tree.
038         */
039        List<TreeNode<T>> getRootNodes();
040    
041        /**
042         * Locates a node in the tree by its unique id.
043         * 
044         * @throws IllegalArgumentException
045         *             if no such node exists
046         * @see TreeNode#getId()
047         */
048        TreeNode<T> getById(String id);
049    
050        /**
051         * Recursively searches from the root nodes to find the tree node that matches
052         * the provided element.
053         * 
054         * @param element
055         *            to search for
056         * @return matching node, or null if not found
057         */
058        TreeNode<T> find(T element);
059    }