/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2010-2011, 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 java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.geotools.data.complex.ComplexFeatureConstants;
import org.geotools.factory.Hints;
import org.geotools.filter.capability.FunctionNameImpl;
import org.opengis.filter.capability.FunctionName;
import org.opengis.filter.expression.Expression;
import org.opengis.filter.expression.ExpressionVisitor;
import org.opengis.filter.expression.Function;
import org.opengis.filter.expression.Literal;
/**
* This function redirects an attribute to be encoded as xlink:href, instead of being encoded as a
* full attribute. This is useful in polymorphism, where static client property cannot be used when
* the encoding is conditional. This function expects:
* <ol>
* <li>Expression: REFERENCE_VALUE (could be another function or literal)
* </ol>
*
* @author Rini Angreani (CSIRO Earth Science and Resource Engineering)
*
*
*
*
* @source $URL$
*/
public class ToXlinkHrefFunction implements Function {
public static final FunctionName NAME = new FunctionNameImpl("toXlinkHref", "REFERENCE_VALUE");
private final List<Expression> parameters;
private final Literal fallback;
public ToXlinkHrefFunction() {
this(new ArrayList<Expression>(), null);
}
public ToXlinkHrefFunction(List<Expression> parameters, Literal fallback) {
this.parameters = parameters;
this.fallback = fallback;
}
public String getName() {
return NAME.getName();
}
public FunctionName getFunctionName() {
return NAME;
}
public List<Expression> getParameters() {
return Collections.unmodifiableList(parameters);
}
public Literal getFallbackValue() {
return fallback;
}
public Object accept(ExpressionVisitor visitor, Object extraData) {
return visitor.visit(this, extraData);
}
public Object evaluate(Object object) {
return evaluate(object, Hints.class);
}
@SuppressWarnings("unchecked")
public <T> T evaluate(Object object, Class<T> context) {
return (T) new Hints(ComplexFeatureConstants.STRING_KEY, parameters.get(0).evaluate(object,
String.class));
}
}