/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2005, Open Geospatial Consortium Inc.
*
* All Rights Reserved. http://www.opengis.org/legal/
*/
package org.opengis.filter.expression;
// Annotations
import org.opengis.annotation.XmlElement;
/**
* Instances of this interface provide a constant, literal value that can be
* used in expressions.
* <p>
* The {@link #evaluate evaluate} method of this class must return the same
* value as {@link #getValue()}.
* </p>
* <p>
* It should be noted that content of getValue() may be persisted with with
* XML based technologies. As an example a geoapi Geometry may be written out
* uding GML3, while a JTS Geometry may be written out using GML2. You should
* not assume that the same instance will be made available to all callers,
* please limit your self to pure data objects and don't use Literal to pass
* state or operations between systems.
* <p>
*
*
* @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/filter/expression/Literal.java $
* @version <A HREF="http://www.opengis.org/docs/02-059.pdf">Implementation specification 1.0</A>
* @author Chris Dillard (SYS Technologies)
* @since GeoAPI 2.0
*/
@XmlElement("Literal")
public interface Literal extends Expression {
/**
* Returns the constant value held by this object.
*/
Object getValue();
}