1 files changed, 20 insertions, 1 deletions
diff --git a/src/main/javassist/ClassMap.java b/src/main/javassist/ClassMap.java
index 98e5cc9e..28f646f0 100644
--- a/src/main/javassist/ClassMap.java
+++ b/src/main/javassist/ClassMap.java
@@ -82,7 +82,7 @@ public class ClassMap extends java.util.HashMap {
      * <code>oldname</code> to <code>newname</code>.  See
      * <code>fix</code> method.
      *
-     * @param oldname   the original class name
+     * @param oldname   the original class name.
      * @param newname   the substituted class name.
      * @see #fix(String)
      */
@@ -96,6 +96,25 @@ public class ClassMap extends java.util.HashMap {
             super.put(oldname2, toJvmName(newname));
     }
 
+    /**
+     * Is equivalent to <code>put()</code> except that
+     * the given mapping is not recorded into the hashtable
+     * if another mapping from <code>oldname</code> is
+     * already included. 
+     *
+     * @param oldname       the original class name.
+     * @param newname       the substituted class name.
+     */
+    public void putIfNone(String oldname, String newname) {
+        if (oldname == newname)
+            return;
+
+        String oldname2 = toJvmName(oldname);
+        String s = (String)get(oldname2);
+        if (s == null)
+            super.put(oldname2, toJvmName(newname));
+    }
+
     protected final void put0(Object oldname, Object newname) {
         super.put(oldname, newname);
     }