added missing constructor javadoc description

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/digester/trunk@1140063 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/digester3/binder/AbstractNamespaceUIRIBasedRulesModule.java b/src/main/java/org/apache/commons/digester3/binder/AbstractNamespaceUIRIBasedRulesModule.java
index e79f340..a9635db 100644
--- a/src/main/java/org/apache/commons/digester3/binder/AbstractNamespaceUIRIBasedRulesModule.java
+++ b/src/main/java/org/apache/commons/digester3/binder/AbstractNamespaceUIRIBasedRulesModule.java
@@ -31,6 +31,13 @@
 
     private final String namespaceURI;
 
+    /**
+     * Creates a new (nullable) namespaceURI-based {@link RulesModule} that automatically binds every
+     * rule to the input namespaceURI.
+     *
+     * @param namespaceURI Namespace URI for which this Rule is relevant, or <code>null</code> to match
+     *        independent of namespace.
+     */
     public AbstractNamespaceUIRIBasedRulesModule( /* @Nullable */String namespaceURI )
     {
         this.namespaceURI = namespaceURI;