--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/share/classes/com/sun/source/util/SourcePositions.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2005-2006 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.*;
+
+/**
+ * Provides methods to obtain the position of a Tree within a CompilationUnit.
+ * A position is defined as a simple character offset from the start of a
+ * CompilationUnit where the first character is at offset 0.
+ *
+ * @author Peter von der Ahé
+ * @since 1.6
+ */
+public interface SourcePositions {
+
+    /**
+     * Gets the starting position of tree within file.  If tree is not found within
+     * file, or if the starting position is not available,
+     * return {@link javax.tools.Diagnostic#NOPOS}.
+     * The returned position must be at the start of the yield of this tree, that
+     * is for any sub-tree of this tree, the following must hold:
+     *
+     * <p>
+     * {@code tree.getStartPosition() <= subtree.getStartPosition()} or <br>
+     * {@code tree.getStartPosition() == NOPOS} or <br>
+     * {@code subtree.getStartPosition() == NOPOS}
+     * </p>
+     *
+     * @param file CompilationUnit in which to find tree.
+     * @param tree tree for which a position is sought.
+     * @return the start position of tree.
+     */
+     long getStartPosition(CompilationUnitTree file, Tree tree);
+
+    /**
+     * Gets the ending position of tree within file.  If tree is not found within
+     * file, or if the starting position is not available,
+     * return {@link javax.tools.Diagnostic#NOPOS}.
+     * The returned position must be at the end of the yield of this tree,
+     * that is for any sub-tree of this tree, the following must hold:
+     *
+     * <p>
+     * {@code tree.getEndPosition() >= subtree.getEndPosition()} or <br>
+     * {@code tree.getEndPosition() == NOPOS} or <br>
+     * {@code subtree.getEndPosition() == NOPOS}
+     * </p>
+     *
+     * In addition, the following must hold:
+     *
+     * <p>
+     * {@code tree.getStartPosition() <= tree.getEndPosition()}  or <br>
+     * {@code tree.getStartPosition() == NOPOS} or <br>
+     * {@code tree.getEndPosition() == NOPOS}
+     * </p>
+     *
+     * @param file CompilationUnit in which to find tree.
+     * @param tree tree for which a position is sought.
+     * @return the end position of tree.
+     */
+     long getEndPosition(CompilationUnitTree file, Tree tree);
+
+}