TreePath


1   /**
2    * @(#)TreePath.java    1.3 06/06/12
3    *
4    * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    *
7    * Use and Distribution is subject to the Java Research License available
8    * at <http://wwws.sun.com/software/communitysource/jrl.html>.
9    */
10  
11  package com.sun.source.util;
12  
13  import com.sun.source.tree.*;
14  import java.util.Iterator  ;
15  
16  /**
17   * A path of tree nodes, typically used to represent the sequence of ancestor
18   * nodes of a tree node up to the top level CompilationUnitTree node.
19   *
20   * @author Jonathan Gibbons
21   * @since 1.6
22   */
23  public class TreePath implements Iterable  <Tree> {
24      /**
25       * Gets a tree path for a tree node within a compilation unit.
26       * @return null if the node is not found
27       */
28      public static TreePath getPath(CompilationUnitTree unit, Tree target) {
29      return getPath(new TreePath(unit), target);
30      }
31      
32      /**
33       * Gets a tree path for a tree node within a subtree identified by a TreePath object.
34       * @return null if the node is not found
35       */
36      public static TreePath getPath(TreePath path, Tree target) {
37      path.getClass();
38      target.getClass();
39      
40      class Result extends Error   {
41          static final long serialVersionUID = -5942088234594905625L;
42          TreePath path;
43          Result(TreePath path) {
44          this.path = path;
45          }
46      }
47      class PathFinder extends TreePathScanner<TreePath,Tree> {
48          public TreePath scan(Tree tree, Tree target) {
49          if (tree == target)
50              throw new Result(new TreePath(getCurrentPath(), target));
51          return super.scan(tree, target);
52          }
53      }
54      
55      try {
56          new PathFinder().scan(path, target);
57      } catch (Result result) {
58          return result.path;
59      }
60          return null;
61      }
62      
63      /**
64       * Creates a TreePath for a root node.
65       */
66      public TreePath(CompilationUnitTree t) {
67          this(null, t);
68      }
69      
70      /**
71       * Creates a TreePath for a child node.
72       */
73      public TreePath(TreePath p, Tree t) {
74          if (t.getKind() == Tree.Kind.COMPILATION_UNIT) {
75              compilationUnit = (CompilationUnitTree) t;
76              parent = null; 
77          }
78          else {
79              compilationUnit = p.compilationUnit;
80              parent = p;
81          }
82          leaf = t;
83      }
84      /**
85       * Get the compilation unit associated with this path.
86       */
87      public CompilationUnitTree getCompilationUnit() {
88      return compilationUnit;
89      }
90      
91      /**
92       * Get the leaf node for this path.
93       */
94      public Tree getLeaf() {
95      return leaf;
96      }
97      
98      /**
99       * Get the path for the enclosing node, or null if there is no enclosing node.
100      */
101     public TreePath getParentPath() {
102     return parent;
103     }
104 
105     public Iterator  <Tree> iterator() {
106     return new Iterator  <Tree>() {
107         public boolean hasNext() {
108         return curr.parent != null;
109         }
110         
111         public Tree next() {
112         curr = curr.parent;
113         return curr.leaf;
114         }
115         
116         public void remove() {
117         throw new UnsupportedOperationException  ();
118         }
119         
120         private TreePath curr;
121     };
122     }
123     
124     private CompilationUnitTree compilationUnit;
125     private Tree leaf;
126     private TreePath parent;
127 }
128
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