/*
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2002 The Apache Software Foundation. All rights reserved.
Redistribution and use in source and binary forms, with or without modifica-
tion, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. The end-user documentation included with the redistribution, if any, must
include the following acknowledgment: "This product includes software
developed by the Apache Software Foundation (http://www.apache.org/)."
Alternately, this acknowledgment may appear in the software itself, if
and wherever such third-party acknowledgments normally appear.
4. The names "Apache Cocoon" and "Apache Software Foundation" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
apache@apache.org.
5. Products derived from this software may not be called "Apache", nor may
"Apache" appear in their name, without prior written permission of the
Apache Software Foundation.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This software consists of voluntary contributions made by many individuals
on behalf of the Apache Software Foundation and was originally created by
Stefano Mazzocchi <stefano@apache.org>. For more information on the Apache
Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.cocoon.components.pipeline;
import org.apache.avalon.excalibur.pool.Recyclable;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.*;
import org.apache.cocoon.components.sax.XMLDeserializer;
import org.apache.cocoon.components.sax.XMLSerializer;
import org.apache.cocoon.components.sax.XMLTeePipe;
import org.apache.cocoon.components.saxconnector.SAXConnector;
import org.apache.cocoon.components.store.Store;
import org.apache.cocoon.environment.Environment;
import org.apache.cocoon.transformation.Transformer;
import org.apache.cocoon.xml.XMLConsumer;
import org.apache.cocoon.xml.XMLProducer;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* The CachingEventPipeline
*
* If all components of this event pipeline are cacheable then the whole
* pipeline is also cacheable. If in this case the CacheableEventPipeline interface
* is invoked (e.g. by the CachingStreamPipeline) the CachingEventPipeline
* does not cache! (If it would cache, the response would be cached twice!)
*
* @author <a href="mailto:cziegeler@apache.org">Carsten Ziegeler</a>
* @version CVS $Id: CachingEventPipeline.java,v 1.9 2002/04/06 17:57:54 vgritsenko Exp $
*/
public class CachingEventPipeline
extends AbstractEventPipeline
implements Disposable, CacheableEventPipeline, Recyclable {
/** The store for the cached sax events */
private Store eventCache;
private XMLProducer producer;
private String generatorRole;
private ArrayList transformerRoles = new ArrayList();
private ArrayList notCacheableTransformers = new ArrayList();
private Map validityObjects;
private PipelineCacheKey pipelineCacheKey;
private boolean setupFinished = false;
/** Indicates if the whole pipeline is cacheable */
private boolean cacheable = false;
private int firstNotCacheableTransformerIndex;
public void compose (ComponentManager manager)
throws ComponentException {
super.compose(manager);
this.eventCache = (Store)this.manager.lookup(Store.TRANSIENT_CACHE);
}
/**
* Set the generator.
*/
public void setGenerator (String role, String source, Parameters param)
throws Exception {
super.setGenerator(role, source, param);
this.generatorRole = role;
}
/**
* Add a transformer.
*/
public void addTransformer (String role, String source, Parameters param)
throws Exception {
super.addTransformer(role, source, param);
this.transformerRoles.add(role);
}
/**
* Generate the unique key.
* This key is the <code>PipelineCacheKey</code> for the whole
* EventPipeline.
*
* @param environment The current environment of the request.
* @return The generated key or <code>null</code> if the pipeline
* is currently not cacheable as a whole.
*/
public PipelineCacheKey generateKey(Environment environment)
throws Exception {
this.setup(environment);
return (this.cacheable ? this.pipelineCacheKey : null);
}
/**
* Generate the validity object.
* Before this method can be invoked the generateKey() method
* must be invoked.
*
* @param environment The current environment of the request.
* @return The generated validity objects for the whole pipeline
* or <code>null</code> if the pipeline is currently
* not cacheable.
*/
public Map generateValidity(Environment environment)
throws Exception {
if (this.cacheable) {
return this.validityObjects;
}
return null;
}
/**
* The stream pipeline (or the content aggregator) calls this
* method to tell the event pipeline if it must not cache the result
*/
public void setStreamPipelineCaches(boolean flag) {
// if we are cacheable and this method is called
// reset the pipeline cache key to avoid duplicate caching
if (flag) {
this.pipelineCacheKey = null;
}
}
public boolean process(Environment environment) throws Exception {
this.setup(environment);
// we cache if the pipelinecachekey is available
XMLSerializer xmlSerializer = null;
try {
if (this.pipelineCacheKey != null) {
// now we have the key to get the cached object
CachedEventObject cachedObject = (CachedEventObject)this.eventCache.get(this.pipelineCacheKey);
if (cachedObject != null) {
getLogger().debug("Found cached content for '" + environment.getURI() + "'.");
Iterator validityIterator = validityObjects.keySet().iterator();
ComponentCacheKey validityKey;
boolean valid = true;
while (validityIterator.hasNext() && valid) {
validityKey = (ComponentCacheKey)validityIterator.next();
valid = cachedObject.isValid(validityKey, (CacheValidity)validityObjects.get(validityKey));
if (getLogger().isDebugEnabled()) {
CacheValidity cachedValidity = cachedObject.getCacheValidity(validityKey);
getLogger().debug("Compared cached validity '" + cachedValidity +
"' with new validity '" + validityObjects.get(validityKey) +
"' : " + (valid ? "valid" : "changed"));
}
}
if (valid) {
getLogger().debug("Using valid cached content for '" + environment.getURI() + "'.");
// get all transformers which are not cacheable
int transformerSize = this.transformers.size();
while (this.firstNotCacheableTransformerIndex < transformerSize) {
this.notCacheableTransformers.add(this.transformers.get(this.firstNotCacheableTransformerIndex));
this.firstNotCacheableTransformerIndex++;
}
XMLDeserializer deserializer = null;
try {
deserializer = (XMLDeserializer)this.manager.lookup(XMLDeserializer.ROLE);
// connect the pipeline:
this.producer = deserializer;
this.connectPipeline(environment,
notCacheableTransformers,
null);
// execute the pipeline:
deserializer.deserialize(cachedObject.getSAXFragment());
} catch ( ProcessingException e ) {
throw e;
} catch ( Exception e ) {
throw new ProcessingException(
"Failed to execute pipeline.",
e
);
} finally {
this.manager.release(deserializer);
}
} else {
getLogger().debug("Cached content is invalid for '" + environment.getURI() + "'.");
// remove invalid cached object
this.eventCache.remove(this.pipelineCacheKey);
cachedObject = null;
}
}
if (cachedObject == null) {
getLogger().debug("Caching content for further requests of '" + environment.getURI() + "'.");
xmlSerializer = (XMLSerializer)this.manager.lookup(XMLSerializer.ROLE);
}
}
if (this.producer == null) {
// the content was not cached/or is invalid
this.producer = this.generator;
this.connectPipeline(environment,
this.transformers,
xmlSerializer);
// execute the pipeline:
this.generator.generate();
// did we have cacheable components?
if (xmlSerializer != null) {
this.eventCache.store(this.pipelineCacheKey,
new CachedEventObject(this.validityObjects,
xmlSerializer.getSAXFragment()));
}
}
} finally {
this.manager.release(xmlSerializer);
}
return true;
}
/**
* Setup the evenet pipeline.
* The components of the pipeline are checked if they are
* Cacheable.
*/
private void setup(Environment environment) throws Exception {
if (this.setupFinished) {
return;
}
if (!this.checkPipeline()) {
throw new ProcessingException("Attempted to process incomplete pipeline.");
}
// set up all sitemap components
this.setupPipeline(environment);
this.firstNotCacheableTransformerIndex = 0;
// is the generator cacheable?
if (this.generator instanceof Cacheable) {
long key = ((Cacheable)this.generator).generateKey();
CacheValidity validity = ((Cacheable)this.generator).generateValidity();
// final check, the current generator might not be cacheable
if (key != 0 && validity != null) {
ComponentCacheKey cck = new ComponentCacheKey(
ComponentCacheKey.ComponentType_Generator,
this.generatorRole,
key);
this.validityObjects = new HashMap();
this.validityObjects.put(cck, validity);
this.pipelineCacheKey = new PipelineCacheKey();
this.pipelineCacheKey.addKey(cck);
// now testing transformers
Transformer trans;
ComponentCacheKey transCacheKey;
int transformerSize = this.transformers.size();
long transKey;
CacheValidity transValidity;
boolean testTrans = true;
while (this.firstNotCacheableTransformerIndex < transformerSize
&& testTrans) {
trans = (Transformer)this.transformers.get(this.firstNotCacheableTransformerIndex);
if (trans instanceof Cacheable) {
transKey = ((Cacheable)trans).generateKey();
transValidity = ((Cacheable)trans).generateValidity();
if (transKey != 0 && transValidity != null) {
transCacheKey = new ComponentCacheKey(
ComponentCacheKey.ComponentType_Transformer,
(String)this.transformerRoles.get(this.firstNotCacheableTransformerIndex),
transKey);
this.pipelineCacheKey.addKey(transCacheKey);
this.validityObjects.put(transCacheKey, transValidity);
} else {
testTrans = false;
}
} else {
testTrans = false;
}
if (testTrans) {
this.firstNotCacheableTransformerIndex++;
}
}
// all transformers are cacheable => pipeline is cacheable
if (this.firstNotCacheableTransformerIndex == transformerSize) {
this.cacheable = true;
}
}
}
this.setupFinished = true;
}
/** Connect the pipeline.
*/
private void connectPipeline(Environment environment,
ArrayList usedTransformers,
XMLSerializer xmlSerializer)
throws ProcessingException {
XMLProducer prev = this.producer;
XMLConsumer next;
boolean configuredSAXConnector = this.manager.hasComponent(SAXConnector.ROLE);
try {
int cacheableTransformerCount = this.firstNotCacheableTransformerIndex;
Iterator itt = usedTransformers.iterator();
while ( itt.hasNext() ) {
if (configuredSAXConnector) {
// connect SAXConnector
SAXConnector connect = (SAXConnector) this.manager.lookup(SAXConnector.ROLE);
connect.setup(environment,environment.getObjectModel(),null,null);
this.connectors.add(connect);
next = connect;
prev.setConsumer(next);
prev = connect;
}
// Connect next component.
next = (XMLConsumer) itt.next();
if (xmlSerializer != null) {
if (cacheableTransformerCount == 0) {
next = new XMLTeePipe(next, xmlSerializer);
xmlSerializer = null;
} else {
cacheableTransformerCount--;
}
}
prev.setConsumer(next);
prev = (XMLProducer) next;
}
if (configuredSAXConnector) {
// insert SAXConnector
SAXConnector connect = (SAXConnector) this.manager.lookup(SAXConnector.ROLE);
connect.setup(environment,environment.getObjectModel(),null,null);
this.connectors.add(connect);
next = connect;
prev.setConsumer(next);
prev = connect;
}
// insert this consumer
next = super.xmlConsumer;
if (xmlSerializer != null) {
next = new XMLTeePipe(next, xmlSerializer);
xmlSerializer = null;
}
prev.setConsumer(next);
} catch ( IOException e ) {
throw new ProcessingException(
"Could not connect pipeline.",
e
);
} catch ( SAXException e ) {
throw new ProcessingException(
"Could not connect pipeline.",
e
);
} catch ( ComponentException e ) {
throw new ProcessingException(
"Could not connect pipeline.",
e
);
}
}
public void recycle() {
getLogger().debug("Recycling of CachingEventPipeline");
super.recycle();
this.producer = null;
this.generatorRole = null;
this.transformerRoles.clear();
this.notCacheableTransformers.clear();
this.validityObjects = null;
this.pipelineCacheKey = null;
this.setupFinished = false;
this.cacheable = false;
}
public void dispose() {
this.manager.release(this.eventCache);
super.dispose();
}
}