001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  You may obtain a copy of the License at
009     *  
010     *    http://www.apache.org/licenses/LICENSE-2.0
011     *  
012     *  Unless required by applicable law or agreed to in writing,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License. 
018     *  
019     */
020    package org.apache.directory.shared.ldap.util.tree;
021    
022    
023    /**
024     * An interface for nodes in a tree designed to quickly lookup hierarchical DN.
025     * Branch nodes in this tree contain other nodes.  Leaf nodes in the tree
026     * contain a reference to an object  whose suffix is the path through the 
027     * nodes of the tree from the root.
028     * 
029     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030     */
031    public interface DnNode<N>
032    {
033        /**
034         * Tells if the implementation is a leaf node. If it's a branch node
035         * then false is returned.
036         *
037         * @return <code>true</code> if the class is a leaf node, false otherwise.
038         */
039        boolean isLeaf();
040        
041        
042        /**
043         * Returns the number of entries under this node. It includes
044         * the node itself, plus the sum of all it children and descendents.
045         *
046         * @return The number of descendents
047         */
048        int size();
049    }