Added code to check if a named field has been modified, added code to

check if all the modified fields are within a particular subset of fields.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1209 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/jdbc/jora/FieldMask.java

@@ -1,9 +1,9 @@
 //
-// $Id: FieldMask.java,v 1.2 2002/05/11 20:29:27 mdb Exp $
+// $Id: FieldMask.java,v 1.3 2003/08/26 04:49:05 eric Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Michael Bayne
-// 
+//
 // This library is free software; you can redistribute it and/or modify it
 // under the terms of the GNU Lesser General Public License as published
 // by the Free Software Foundation; either version 2.1 of the License, or
@@ -22,6 +22,8 @@ package com.samskivert.jdbc.jora;
 
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
 
 /**
  * Provides support for doing partial updates to objects in a JORA table.
@@ -81,6 +83,36 @@ public class FieldMask
         return _modified[index];
     }
 
+    /**
+     * Returns true if the field with the specified name is modifed.
+     */
+    public final boolean isModified (String fieldName)
+    {
+        Integer index = (Integer)_descripMap.get(fieldName);
+        if (index == null) {
+            String errmsg = "Passed in field not in mask.";
+            throw new IllegalArgumentException(errmsg);
+        }
+        return _modified[index.intValue()];
+    }
+
+    /**
+     * Takes a subset of the fields represented by this field mask.
+     * Returns true only if the modified fields intersect the subsetFields.
+     */
+    public final boolean onlySubSetModified (HashSet subsetFields)
+    {
+        Iterator itr = _descripMap.keySet().iterator();
+        while (itr.hasNext()) {
+            String field = (String)itr.next();
+            if (isModified(field) && (!subsetFields.contains(field))) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     /**
      * Marks the specified field as modified.
      */