/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2004-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.filter;
import org.opengis.filter.expression.Expression;
/**
* Takes an AttributeExpression, and computes the length of the data for the attribute.
*
* @author dzwiers
*
* @source $URL$
*/
public class LengthFunction extends FunctionExpressionImpl {
public LengthFunction(){
super("length");
}
/* (non-Javadoc)
* @see org.geotools.filter.FunctionExpressionImpl#getArgCount()
*/
public int getArgCount() {
return 1;
}
/* (non-Javadoc)
* @see org.geotools.filter.Expression#getValue(org.geotools.feature.Feature)
*/
public Object evaluate(Object feature) {
Expression ae = (Expression)getParameters().get(0);
String value = (String) ae.evaluate(feature, String.class);
return new Integer(value == null? 0 : value.length());
}
}