/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.gdata.search.analysis;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.apache.lucene.gdata.data.ServerBaseEntry;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import com.google.gdata.data.ExtensionProfile;
import com.google.gdata.util.common.xml.XmlWriter;
/**
* <tt>Indexable</tt> implementation using the W3C Dom API and JAXP XPath
* engine
*
* @author Simon Willnauer
* @param <R> -
* a subtype of {@link org.w3c.dom.Node} returned by the applyPath
* method
* @param <I> -
* a subtype of {@link org.apache.lucene.gdata.data.ServerBaseEntry}
*/
public class DomIndexable<R extends Node, I extends ServerBaseEntry> extends
Indexable<R, I> {
private final Document document;
private final XPath xPath;
/**
* @param applyAble
* @throws NotIndexableException
*/
public DomIndexable(I applyAble) throws NotIndexableException {
super(applyAble);
if (this.applyAble.getServiceConfig() == null)
throw new NotIndexableException("ServiceConfig is not set");
try {
this.document = buildDomDocument();
} catch (ParserConfigurationException e) {
throw new NotIndexableException("Can not create document builder",
e);
} catch (IOException e) {
throw new NotIndexableException(
"IO Exception occurred while building indexable", e);
} catch (SAXException e) {
throw new NotIndexableException("Can not parse entry", e);
}
this.xPath = XPathFactory.newInstance().newXPath();
}
private Document buildDomDocument() throws ParserConfigurationException,
IOException, SAXException {
StringWriter stringWriter = new StringWriter();
ExtensionProfile profile = this.applyAble.getServiceConfig()
.getExtensionProfile();
if (profile == null)
throw new IllegalStateException("ExtensionProfile is not set");
XmlWriter writer = new XmlWriter(stringWriter);
this.applyAble.generateAtom(writer, profile);
DocumentBuilder builder = DocumentBuilderFactory.newInstance()
.newDocumentBuilder();
return builder.parse(new InputSource(new StringReader(stringWriter
.toString())));
}
/**
* @see org.apache.lucene.gdata.search.analysis.Indexable#applyPath(java.lang.String)
*/
@SuppressWarnings("unchecked")
@Override
public R applyPath(String expression) throws XPathExpressionException {
return (R) this.xPath.evaluate(expression, this.document,
XPathConstants.NODE);
}
}