added missing javadoc

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/digester/trunk@1140258 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/digester3/AbstractMethodRule.java b/src/main/java/org/apache/commons/digester3/AbstractMethodRule.java
index 60627f8..2611936 100644
--- a/src/main/java/org/apache/commons/digester3/AbstractMethodRule.java
+++ b/src/main/java/org/apache/commons/digester3/AbstractMethodRule.java
@@ -192,6 +192,11 @@
         }
     }
 
+    /**
+     * Just performs the method execution.
+     *
+     * @throws Exception if any error occurs.
+     */
     private void invoke()
         throws Exception
     {
@@ -240,8 +245,18 @@
         }
     }
 
+    /**
+     * Returns the argument object of method has to be invoked.
+     *
+     * @return the argument object of method has to be invoked.
+     */
     protected abstract Object getChild();
 
+    /**
+     * Returns the target object of method has to be invoked.
+     *
+     * @return the target object of method has to be invoked.
+     */
     protected abstract Object getParent();
 
     /**