/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2006-2008, 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.expression;

import org.geotools.util.Converters;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.filter.expression.Expression;
import org.opengis.filter.expression.ExpressionVisitor;
//
/**
 * Abstract superclass of these Expression implementations.
 * <p>
 * Contains additional support for "Expression chaining". This allows
 * Expressions to be constructed as a chain of Java commands similar to the use
 * of the java collections api.
 * </p>
 * <p>
 * Note: Expression chaining is a simple developer convience, it has no effect
 * on the data model exposed by the GeoAPI interfaces.
 * </p>
 * <p>
 * Idea: We may also be able to teach this implementation to make use of
 * JXPath to extract "attribute values" from Java Beans, DOM, JDOM in addition
 * to the geotools & geoapi FeatureType models. It is a cunning plan - any
 * implementation will make use of this abstract base class.
 * </p>
 * 
 * @author Jody Garnett
 *
 * @source $URL$
 */
public abstract class ExpressionAbstract implements Expression {

    /**
     * Subclass should override, default implementation returns null.
     * 
     * @return default implementation returns null
     */
    public Object evaluate(Object object) {
        return null;
    }
    /**
     * Default implementation delegates handling of context
     * conversion to Value utility class.
     * <p>
     * Subclasses are expected to make use of the Value utility class
     * (as the easiest way to provide value morphing in confirmance with
     *  the Filter specification).
     */
    public <T> T evaluate(Object object, Class<T> context) {
        return Converters.convert(evaluate(object), context);
    }

}

@@ -948,657 +948,8 @@
 ns.%0A
- * %3Cp%3E%0A * Contains additional support for %22Expression chaining%22. This allows%0A * Expressions to be constructed as a chain of Java commands similar to the use%0A * of the java collections api.%0A * %3C/p%3E%0A * %3Cp%3E%0A * Note: Expression chaining is a simple developer convience, it has no effect%0A * on the data model exposed by the GeoAPI interfaces.%0A * %3C/p%3E%0A * %3Cp%3E%0A * Idea: We may also be able to teach this implementation to make use of%0A * JXPath to extract %22attribute values%22 from Java Beans, DOM, JDOM in addition%0A * to the geotools & geoapi FeatureType models. It is a cunning plan - any%0A * implementation will make use of this abstract base class.%0A * %3C/p%3E%0A
  * %0A
@@ -1367,21 +1367,26 @@
 sion to 
-Value
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  utility
@@ -1458,13 +1458,31 @@
 the 
-Value
+%7B@linkplain Converters%7D
  uti
@@ -1552,17 +1552,17 @@
  in conf
-i
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remove developer notes javadoc