package org.geotools.filter;
/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2009, 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.
*/
import org.geotools.data.complex.XmlMappingFeatureIterator;
import org.geotools.data.complex.xml.XmlXpathFilterData;
import org.geotools.filter.FunctionExpressionImpl;
import org.geotools.filter.capability.FunctionNameImpl;
import org.geotools.util.XmlXpathUtilites;
import org.jdom.Document;
import org.opengis.filter.capability.FunctionName;
import org.xml.sax.helpers.NamespaceSupport;
/**
* This is used for app-schema with web-service backend, where a function could have an xpath to the
* web service as a parameter. E.g. strConcat('gsml.', gss:geologicEvent/@id). The expression would
* throw a CQLParser exception, as it doesn't allow for special characters. This function is to wrap
* the xpath expression, evaluate against the document and return the value. E.g. strConcat('gsml.',
* asXpath('gss:geologicEvent/@id'))
* <p>
* This function expects:
* <ol>
* <li>Expression: an xpath to underlying web service
* </ol>
*
* @author Rini Angreani (CSIRO Earth Science and Resource Engineering)
*
*
* @source $URL$
* http://svn.osgeo.org/geotools/trunk/modules/unsupported/app-schema/webservice/src/main
* /java/org/geotools/filter/AsXpathFunctionExpression.java $
*/
public class AsXpathFunctionExpression extends FunctionExpressionImpl {
/**
* Make the instance of FunctionName available in a consistent spot.
*/
public static final FunctionName NAME = new FunctionNameImpl("asXpath", "XPATH");
public AsXpathFunctionExpression() {
super(NAME.getName());
functionName = NAME;
}
public Object evaluate(Object object) {
if (object == null || !(object instanceof XmlXpathFilterData)) {
return null;
}
XmlXpathFilterData data = (XmlXpathFilterData) object;
Document doc = data.getDoc();
String xpath = data.getItemXpath();
NamespaceSupport ns = data.getNamespaces();
// append the parameter from AsXpath() to the prefix
xpath += XmlMappingFeatureIterator.XPATH_SEPARATOR
+ (params.get(0) == null ? "" : params.get(0).toString());
// then evaluate xpath from the xmlResponse
return XmlXpathUtilites.getSingleXPathValue(ns, xpath, doc);
}
}