001    // Copyright 2004, 2005 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.tapestry.contrib.tree.model;
016    
017    import java.util.Iterator;
018    
019    /**
020     * The interface that defines a suitable data model for a <code>TreeView component</code>. 
021     * 
022     * @author ceco
023     */
024    public interface ITreeDataModel
025    {
026            /**
027             * Returns the root node of the tree
028             */
029            Object getRoot();
030    
031            /**
032             * Returns the number of children of parent node.
033             * @param objParent is the parent object whose nr of children are sought
034             */
035            int getChildCount(Object objParent);
036    
037            /**
038             * Get an iterator to the Collection of children belonging to the parent node object
039             * @param objParent is the parent object whose children are requested
040             */
041            Iterator getChildren(Object objParent);
042    
043            /**
044             * Get the actual node object based on some identifier (for example an UUID)
045             * @param objUniqueKey is the unique identifier of the node object being retrieved
046             * @return the instance of the node object identified by the key
047             */
048            Object getObject(Object objUniqueKey);
049    
050            /** 
051             * Get the unique identifier (UUID) of the node object with a certain parent node
052             * @param objTarget is the Object whose identifier is required
053             * @param objParentUniqueKey is the unique id of the parent of objTarget
054             * @return the unique identifier of objTarget
055             */
056            Object getUniqueKey(Object objTarget, Object objParentUniqueKey);
057    
058            /**
059             * Get the unique identifier of the parent of an object
060             * @param objChildUniqueKey is the identifier of the Object for which the parent identifier is sought
061             * @return the identifier (possibly UUID) of the parent of objChildUniqueKey
062             */
063            Object getParentUniqueKey(Object objChildUniqueKey);
064    
065            /**
066             * Check to see (on the basis of some node object identifier) whether the parent node is indeed the parent of the object
067             * @param objChildUniqueKey is the identifier of the object whose parent is being checked
068             * @param objParentUniqueKey is the identifier of the parent which is to be checked against
069             */
070            boolean isAncestorOf(Object objChildUniqueKey, Object objParentUniqueKey);
071            
072    }