/*
* 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.lenya.modules.metadata;
import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.generation.ServiceableGenerator;
import org.apache.excalibur.source.SourceValidity;
import org.apache.excalibur.source.impl.validity.TimeStampValidity;
import org.apache.excalibur.xml.dom.DOMParser;
import org.apache.lenya.cms.cocoon.source.RepositorySource;
import org.apache.lenya.cms.metadata.MetaData;
import org.apache.lenya.cms.metadata.MetaDataException;
import org.apache.lenya.cms.repository.ContentHolder;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
/**
* <p>
* Generates the meta data of a document. The <code>src</code> attribute must be
* a {@link RepositorySource} URI (e.g., <code>lenya-document:...</code>).
* </p>
* <p>
* For multi-value elements, multiple <prefix:key> elements are generated.
* </p>
* <p>
* Example output:
* </p>
*
* <pre>
* <meta:metadata xmlns:meta="http://apache.org/cocoon/lenya/metadata/1.0">
* <elements xmlns="http://purl.org/dc/elements/1.1/">
* <title>Search</title>
* <date>2006-06-12 13:43:14</date>
* <language>en</language>
* <creator>lenya</creator>
* </elements>
* <elements xmlns="http://apache.org/lenya/metadata/document/1.0">
* <extension>xml</extension>
* <resourceType>usecase</resourceType>
* <contentType>xml</contentType>
* </elements>
* </meta:metadata>
* </pre>
*/
public class LenyaMetaDataGenerator extends ServiceableGenerator implements
CacheableProcessingComponent {
/** Node and attribute names */
protected AttributesImpl attributes;
/** Metadata */
protected static final String ROOT_META_NODE_NAME = "meta";
/** The URI of the namespace of the metadata */
protected static final String URI_META = "http://apache.org/cocoon/lenya/metadata/1.0";
/** The namespace prefix for this namespace */
protected static final String PREFIX_META = "lenya";
/** The parser for the XML snippets to be included. */
protected DOMParser parser = null;
private String src;
/** The repository content holder to generate the meta data for */
private ContentHolder content;
private SourceValidity validity;
/**
* Recycle this component. All instance variables are set to <code>null</code>.
*/
public void recycle() {
this.content = null;
this.src = null;
this.parser = null;
this.validity = null;
super.recycle();
}
/**
* Serviceable
*
* @param manager the ComponentManager
*
* @throws ServiceException in case a component could not be found
*/
public void service(ServiceManager manager) throws ServiceException {
super.service(manager);
this.parser = (DOMParser) manager.lookup(DOMParser.ROLE);
this.attributes = new AttributesImpl();
}
/**
* Setup the file generator. Try to get the last modification date of the source for caching.
*/
public void setup(SourceResolver resolver, Map objectModel, String src, Parameters par)
throws ProcessingException, SAXException, IOException {
super.setup(resolver, objectModel, src, par);
this.src = src;
RepositorySource source = null;
try {
source = (RepositorySource) resolver.resolveURI(src);
this.content = source.getContent();
this.validity = source.getValidity();
} catch (Exception e) {
throw new RuntimeException(e);
}
finally {
if (source != null) {
resolver.release(source);
}
}
}
/**
* 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.src;
}
/**
* Generate the validity object.
*
* @return The generated validity object or <code>null</code> if the component is currently
* not cacheable.
*/
public SourceValidity getValidity() {
return this.validity;
}
/**
* Generate XML data.
*/
public void generate() throws IOException, SAXException, ProcessingException {
startNodeRoot();
performIncludesMeta();
endNodeRoot();
}
private void performIncludesMeta() throws SAXException, ProcessingException {
try {
String[] namespaces = this.content.getMetaDataNamespaceUris();
for (int i = 0; i < namespaces.length; i++) {
this.contentHandler.startPrefixMapping("", namespaces[i]);
startNodeMeta(namespaces[i]);
parseMetaData(namespaces[i]);
endNodeMeta(namespaces[i]);
this.contentHandler.endPrefixMapping("");
}
} catch (MetaDataException e) {
throw new ProcessingException(e);
}
}
private void parseMetaData(String namespace) throws ProcessingException, SAXException {
MetaData metaData = getMetaData(namespace);
String[] names = metaData.getAvailableKeys();
for (int i = 0; i < names.length; i++) {
String[] values;
try {
values = metaData.getValues(names[i]);
} catch (MetaDataException e) {
throw new ProcessingException(e);
}
for (int j = 0; j < values.length; j++) {
this.contentHandler.startElement(namespace, names[i], names[i],
new AttributesImpl());
char[] valueChars = values[j].toCharArray();
this.contentHandler.characters(valueChars, 0, valueChars.length);
this.contentHandler.endElement(namespace, names[i], names[i]);
}
}
}
private void endNodeRoot() throws SAXException {
this.contentHandler.endElement(URI_META, "metadata", PREFIX_META + ":metadata");
this.contentHandler.endPrefixMapping(PREFIX_META);
this.contentHandler.endDocument();
}
private void startNodeRoot() throws SAXException {
this.contentHandler.startDocument();
this.contentHandler.startPrefixMapping(PREFIX_META, URI_META);
this.contentHandler.startElement(URI_META, "metadata", PREFIX_META + ":metadata",
attributes);
}
private void startNodeMeta(String namespace) throws SAXException {
this.contentHandler.startElement(namespace, "elements", "elements", attributes);
}
private void endNodeMeta(String namespace) throws SAXException {
this.contentHandler.endElement(namespace, "elements", "elements");
}
protected MetaData getMetaData(String namespaceUri) throws ProcessingException {
try {
return this.content.getMetaData(namespaceUri);
} catch (Exception e1) {
throw new ProcessingException("Obtaining meta data value for [" + this.content
+ "] failed: ", e1);
}
}
}