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langtools/src/share/classes/com/sun/source/util/TreePath.java

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+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package com.sun.source.util;
+
+import com.sun.source.tree.*;
+import java.util.Iterator;
+
+/**
+ * A path of tree nodes, typically used to represent the sequence of ancestor
+ * nodes of a tree node up to the top level CompilationUnitTree node.
+ *
+ * @author Jonathan Gibbons
+ * @since 1.6
+ */
+public class TreePath implements Iterable<Tree> {
+    /**
+     * Gets a tree path for a tree node within a compilation unit.
+     * @return null if the node is not found
+     */
+    public static TreePath getPath(CompilationUnitTree unit, Tree target) {
+        return getPath(new TreePath(unit), target);
+    }
+
+    /**
+     * Gets a tree path for a tree node within a subtree identified by a TreePath object.
+     * @return null if the node is not found
+     */
+    public static TreePath getPath(TreePath path, Tree target) {
+        path.getClass();
+        target.getClass();
+
+        class Result extends Error {
+            static final long serialVersionUID = -5942088234594905625L;
+            TreePath path;
+            Result(TreePath path) {
+                this.path = path;
+            }
+        }
+        class PathFinder extends TreePathScanner<TreePath,Tree> {
+            public TreePath scan(Tree tree, Tree target) {
+                if (tree == target)
+                    throw new Result(new TreePath(getCurrentPath(), target));
+                return super.scan(tree, target);
+            }
+        }
+
+        try {
+            new PathFinder().scan(path, target);
+        } catch (Result result) {
+            return result.path;
+        }
+        return null;
+    }
+
+    /**
+     * Creates a TreePath for a root node.
+     */
+    public TreePath(CompilationUnitTree t) {
+        this(null, t);
+    }
+
+    /**
+     * Creates a TreePath for a child node.
+     */
+    public TreePath(TreePath p, Tree t) {
+        if (t.getKind() == Tree.Kind.COMPILATION_UNIT) {
+            compilationUnit = (CompilationUnitTree) t;
+            parent = null;
+        }
+        else {
+            compilationUnit = p.compilationUnit;
+            parent = p;
+        }
+        leaf = t;
+    }
+    /**
+     * Get the compilation unit associated with this path.
+     */
+    public CompilationUnitTree getCompilationUnit() {
+        return compilationUnit;
+    }
+
+    /**
+     * Get the leaf node for this path.
+     */
+    public Tree getLeaf() {
+        return leaf;
+    }
+
+    /**
+     * Get the path for the enclosing node, or null if there is no enclosing node.
+     */
+    public TreePath getParentPath() {
+        return parent;
+    }
+
+    public Iterator<Tree> iterator() {
+        return new Iterator<Tree>() {
+            public boolean hasNext() {
+                return curr.parent != null;
+            }
+
+            public Tree next() {
+                curr = curr.parent;
+                return curr.leaf;
+            }
+
+            public void remove() {
+                throw new UnsupportedOperationException();
+            }
+
+            private TreePath curr;
+        };
+    }
+
+    private CompilationUnitTree compilationUnit;
+    private Tree leaf;
+    private TreePath parent;
+}