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Java > Open Source Codes > org > apache > cayenne > util > BaseTreeVisitor


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19
20 package org.apache.cayenne.util;
21
22 import java.util.HashMap JavaDoc;
23 import java.util.Map JavaDoc;
24
25 import org.apache.cayenne.project.ProjectPath;
26
27 /**
28  * A common superclass for specialized tree visitors. Can also be used as a noop
29  * pass-through visitor for nodes that need no processing by themselves.
30  *
31  * @author Andrus Adamchik
32  */
33 // TODO, andrus, 4/24/2006 - move to Cayenne core in 2.0
34 public class BaseTreeVisitor implements HierarchicalTreeVisitor {
35
36     protected Map JavaDoc childVisitors;
37     protected boolean terminatingOnNoChildVisitor;
38
39     public BaseTreeVisitor() {
40         this.terminatingOnNoChildVisitor = true;
41     }
42
43     public boolean isTerminatingOnNoChildVisitor() {
44         return terminatingOnNoChildVisitor;
45     }
46
47     public void setTerminatingOnNoChildVisitor(boolean terminatingOnNoChildVisitor) {
48         this.terminatingOnNoChildVisitor = terminatingOnNoChildVisitor;
49     }
50
51     public HierarchicalTreeVisitor childVisitor(ProjectPath path, Class JavaDoc childType) {
52         if (childVisitors == null) {
53             return terminatingOnNoChildVisitor ? null : this;
54         }
55
56         HierarchicalTreeVisitor childVisitor = (HierarchicalTreeVisitor) childVisitors
57                 .get(childType.getName());
58         return childVisitor != null ? childVisitor : terminatingOnNoChildVisitor
59                 ? null
60                 : this;
61     }
62
63     public void onFinishNode(ProjectPath path) {
64     }
65
66     public boolean onStartNode(ProjectPath path) {
67         return true;
68     }
69
70     public void addChildVisitor(Class JavaDoc childClass, HierarchicalTreeVisitor visitor) {
71         if (childVisitors == null) {
72             childVisitors = new HashMap JavaDoc();
73         }
74
75         childVisitors.put(childClass.getName(), visitor);
76     }
77 }
78
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