/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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.cocoon.generation;
import java.io.Serializable;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.cocoon.ResourceNotFoundException;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.components.sax.XMLDeserializer;
import org.apache.excalibur.source.SourceValidity;
import org.apache.excalibur.source.impl.validity.NOPValidity;
import org.apache.excalibur.store.Store;
import org.xml.sax.SAXException;
/**
* The generation half of FragmentExtractor.
*
* FragmentExtractor is a transformer-generator pair which is designed to allow
* sitemap managers to extract certain nodes from a SAX stream and move them
* into a separate pipeline. The main use for this is to extract inline SVG
* images and serve them up through a separate pipeline, usually serializing
* them to PNG or JPEG format first.
*
* This is by no means complete yet, but it should prove useful, particularly
* for offline generation.
*
* @author <a href="mailto:paul@luminas.co.uk">Paul Russell</a>
* @version CVS $Id: FragmentExtractorGenerator.java 224618 2005-07-24 13:42:15Z joerg $
*/
public class FragmentExtractorGenerator extends ServiceableGenerator
implements CacheableProcessingComponent {
/**
* Generate the unique key.
* This key must be unique inside the space of this component.
*
* @return The generated key hashes the src
*/
public Serializable getKey() {
return this.source;
}
/**
* Generate the validity object.
*
* @return The generated validity object or <code>null</code> if the
* component is currently not cacheable.
*/
public SourceValidity getValidity() {
return NOPValidity.SHARED_INSTANCE;
}
public void generate() throws SAXException, ProcessingException {
// Obtain the fragmentID (which is simply the filename portion of the source)
if (getLogger().isDebugEnabled()) {
getLogger().debug("Retrieving fragment " + source + ".");
}
Store store = null;
XMLDeserializer deserializer = null;
Object fragment = null;
try {
store = (Store) this.manager.lookup(Store.TRANSIENT_STORE);
fragment = store.get(source);
if (fragment == null) {
throw new ResourceNotFoundException("Could not find fragment " + source + " in store");
}
deserializer = (XMLDeserializer) this.manager.lookup(XMLDeserializer.ROLE);
deserializer.setConsumer(this.xmlConsumer);
deserializer.deserialize(fragment);
} catch (ServiceException ce) {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Could not lookup for component.", ce);
}
throw new SAXException("Could not lookup for component.", ce);
} finally {
this.manager.release(store);
this.manager.release(deserializer);
}
}
}