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Java > Open Source Codes > org > objectstyle > cayenne > project > FlatProjectView


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
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6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
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22  * must include the following acknowlegement:
23  * "This product includes software developed by independent contributors
24  * and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
25  * Alternately, this acknowlegement may appear in the software itself,
26  * if and wherever such third-party acknowlegements normally appear.
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28  * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
29  * or promote products derived from this software without prior written
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31  * "andrus at objectstyle dot org".
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35  * names without prior written permission.
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51  * This software consists of voluntary contributions made by many
52  * individuals and hosted on ObjectStyle Group web site. For more
53  * information on the ObjectStyle Group, please see
54  * <http://objectstyle.org/>.
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56 package org.objectstyle.cayenne.project;
57
58 import java.util.ArrayList JavaDoc;
59 import java.util.List JavaDoc;
60
61 import org.objectstyle.cayenne.access.DataNode;
62
63 /**
64  * FlatProjectView converts a project tree into a list of nodes,
65  * thus flattening the tree. Normally used as a singleton.
66  *
67  * @author Andrei Adamchik
68  */
69 public class FlatProjectView {
70
71     protected static FlatProjectView instance = new FlatProjectView();
72
73     /**
74      * Returns a FlatProjectView singleton.
75      */
76     public static FlatProjectView getInstance() {
77         return instance;
78     }
79
80     /**
81      * Returns flat tree view.
82      */
83     public List JavaDoc flattenProjectTree(Object JavaDoc rootNode) {
84         List JavaDoc nodes = new ArrayList JavaDoc();
85         TraversalHelper helper = new TraversalHelper(nodes);
86         new ProjectTraversal(helper).traverse(rootNode);
87         return nodes;
88     }
89
90     /**
91      * Helper class that serves as project traversal helper.
92      */
93     class TraversalHelper implements ProjectTraversalHandler {
94         protected List JavaDoc nodes;
95
96         public TraversalHelper(List JavaDoc nodes) {
97             this.nodes = nodes;
98         }
99
100         public void projectNode(ProjectPath path) {
101             nodes.add(path);
102         }
103
104         /**
105          * Returns true unless an object is a DataNode.
106          */
107         public boolean shouldReadChildren(
108             Object JavaDoc node,
109             ProjectPath parentPath) {
110             // don't read linked maps
111 return !(node instanceof DataNode);
112         }
113     }
114 }
115
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