/**
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig 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.jasig.portal.rendering.cache;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import org.jasig.portal.rendering.PipelineComponentWrapper;
import org.jasig.portal.rendering.PipelineEventReader;
import org.jasig.portal.rendering.PipelineEventReaderImpl;
import org.jasig.portal.utils.cache.CacheKey;
import org.jasig.resourceserver.aggr.om.Included;
import org.jasig.resourceserver.utils.aggr.ResourcesElementsProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.annotation.Autowired;
/**
* Component that caches events from a wrapped component
*
* @author Eric Dalquist
* @version $Revision$
*/
public abstract class CachingPipelineComponent<R, E> extends PipelineComponentWrapper<R, E> implements BeanNameAware {
protected final Logger logger = LoggerFactory.getLogger(getClass());
private ResourcesElementsProvider resourcesElementsProvider;
private Ehcache cache;
private String beanName;
@Autowired
public void setResourcesElementsProvider(ResourcesElementsProvider resourcesElementsProvider) {
this.resourcesElementsProvider = resourcesElementsProvider;
}
public final void setCache(Ehcache cache) {
this.cache = cache;
}
@Override
public void setBeanName(String name) {
this.beanName = name;
}
@Override
public final CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) {
return this.wrappedComponent.getCacheKey(request, response);
}
/* (non-Javadoc)
* @see org.jasig.portal.rendering.PipelineComponent#getEventReader(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
@SuppressWarnings("unchecked")
@Override
public final PipelineEventReader<R, E> getEventReader(HttpServletRequest request, HttpServletResponse response) {
if (Included.PLAIN == this.resourcesElementsProvider.getDefaultIncludedType()) {
this.logger.trace("{} - Resoure Aggregation Disabled, ignoring event cache and returning parent event reader directly", this.beanName);
return this.wrappedComponent.getEventReader(request, response);
}
//Get the key for this request from the target component and see if there is a cache entry
final CacheKey cacheKey = this.wrappedComponent.getCacheKey(request, response);
Element element = this.cache.get(cacheKey);
CachedEventReader<E> cachedEventReader = null;
if (element != null) {
cachedEventReader = (CachedEventReader<E>)element.getObjectValue();
}
//If there was a cached reader return it immediately
if (cachedEventReader == null) {
//No cached data for key, call target component to get events and an updated cache key
logger.debug("{} - No cached events found for key {}, calling parent", this.beanName, cacheKey);
final PipelineEventReader<R, E> pipelineEventReader = this.wrappedComponent.getEventReader(request, response);
//Copy the events from the reader into a buffer to be cached
final List<E> eventCache = new LinkedList<E>();
for (final E event : pipelineEventReader) {
//TODO add de-duplication logic here
eventCache.add(event);
}
final Map<String, String> outputProperties = pipelineEventReader.getOutputProperties();
cachedEventReader = new CachedEventReader<E>(eventCache, new LinkedHashMap<String, String>(outputProperties));
//Cache the buffer
element = new Element(cacheKey, cachedEventReader);
this.cache.put(element);
logger.debug("{} - Cached {} events for key {}", this.beanName, eventCache.size(), cacheKey);
}
else {
logger.debug("{} - Found cached events for key {}", this.beanName, cacheKey);
}
final List<E> eventCache = cachedEventReader.getEventCache();
final Map<String, String> outputProperties = cachedEventReader.getOutputProperties();
final R eventReader = this.createEventReader(eventCache.listIterator());
return new PipelineEventReaderImpl<R, E>(eventReader, outputProperties);
}
//Ugly!!! Needed because XMLEventReader implements Iterator but does not parameterize it
protected abstract R createEventReader(ListIterator<E> eventCache);
}