--- branches/2.0-RC2/src/skrueger/AttributeMetadata.java	2010/02/03 15:32:21	658
+++ branches/2.0-RC2/src/skrueger/AttributeMetadata.java	2010/02/03 18:05:50	666
@@ -79,7 +79,7 @@
 	 * be set and will always be interpreted as NULL internally and will usually
 	 * be ignored. This overcomes the problem, that 
 	 **/
-	protected HashSet<Object> nodataValues = new HashSet<Object>();
+	protected final HashSet<Object> nodataValues = new HashSet<Object>();
 
 	/** Translation of the attribute's title **/
 	protected Translation title = new Translation();
@@ -340,8 +340,12 @@
 		this.name = name;
 	}
 
-	public void setNodataValues(final HashSet<Object> nodataValues) {
-		this.nodataValues = nodataValues;
+	public void addNodataValue(Object nodataValue) {
+		this.nodataValues.add(nodataValue);
+	}
+	
+	public void removeNodataValue(Object nodataValue) {
+		this.nodataValues.remove(nodataValue);
 	}
 
 	public void setTitle(final Translation title) {
@@ -387,19 +391,14 @@
 	}
 
 	/**
-	 * Takes any value object and checks it againsts the NODATA values. If the
+	 * Takes any value object and checks it against the NODATA values. If the
 	 * value equals a NODATA value, <code>null</code> is returned. Otherwise the
 	 * same object is returned.
 	 * 
 	 * Note: This method is called often.
 	 */
 	public Object fiterNodata(final Object value) {
-
-		// contains.. hash
-		for (final Object nodataValue : getNodataValues()) {
-			if (nodataValue.equals(value))
-				return null;
-		}
+		if (nodataValues.contains(value)) return null;
 		return value;
 	}
 }