/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. 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. For additional information regarding
* copyright in this work, please see the NOTICE file in the top level
* directory of this distribution.
*/
package org.apache.roller.ui.rendering.util.cache;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.roller.RollerException;
import org.apache.roller.config.RollerConfig;
import org.apache.roller.business.RollerFactory;
import org.apache.roller.ui.rendering.util.PlanetRequest;
import org.apache.roller.util.cache.Cache;
import org.apache.roller.util.cache.CacheManager;
import org.apache.roller.util.cache.ExpiringCacheEntry;
/**
* Cache for planet content.
*/
public class PlanetCache {
private static Log log = LogFactory.getLog(PlanetCache.class);
// a unique identifier for this cache, this is used as the prefix for
// roller config properties that apply to this cache
public static final String CACHE_ID = "cache.planet";
// keep cached content
private boolean cacheEnabled = true;
private Cache contentCache = null;
// keep a cached version of last expired time
private ExpiringCacheEntry lastUpdateTime = null;
private long timeout = 15 * 60 * 1000;
// reference to our singleton instance
private static PlanetCache singletonInstance = new PlanetCache();
private PlanetCache() {
cacheEnabled = RollerConfig.getBooleanProperty(CACHE_ID+".enabled");
Map cacheProps = new HashMap();
cacheProps.put("id", CACHE_ID);
Enumeration allProps = RollerConfig.keys();
String prop = null;
while(allProps.hasMoreElements()) {
prop = (String) allProps.nextElement();
// we are only interested in props for this cache
if(prop.startsWith(CACHE_ID+".")) {
cacheProps.put(prop.substring(CACHE_ID.length()+1),
RollerConfig.getProperty(prop));
}
}
log.info("Planet cache = "+cacheProps);
if(cacheEnabled) {
contentCache = CacheManager.constructCache(null, cacheProps);
} else {
log.warn("Caching has been DISABLED");
}
// lookup our timeout value
String timeoutString = RollerConfig.getProperty("cache.planet.timeout");
try {
long timeoutSecs = Long.parseLong(timeoutString);
this.timeout = timeoutSecs * 1000;
} catch(Exception e) {
// ignored ... illegal value
}
}
public static PlanetCache getInstance() {
return singletonInstance;
}
public Object get(String key) {
if(!cacheEnabled)
return null;
Object entry = contentCache.get(key);
if(entry == null) {
log.debug("MISS "+key);
} else {
log.debug("HIT "+key);
}
return entry;
}
public void put(String key, Object value) {
if(!cacheEnabled)
return;
contentCache.put(key, value);
log.debug("PUT "+key);
}
public void remove(String key) {
if(!cacheEnabled)
return;
contentCache.remove(key);
log.debug("REMOVE "+key);
}
public void clear() {
if(!cacheEnabled)
return;
contentCache.clear();
this.lastUpdateTime = null;
log.debug("CLEAR");
}
public Date getLastModified() {
Date lastModified = null;
// first try our cached version
if(this.lastUpdateTime != null) {
lastModified = (Date) this.lastUpdateTime.getValue();
}
// still null, we need to get a fresh value
if(lastModified == null) {
try {
lastModified = RollerFactory.getRoller().getPlanetManager().getLastUpdated();
} catch (RollerException ex) {
log.error("Error getting planet manager", ex);
}
if (lastModified == null) {
lastModified = new Date();
log.warn("Can't get lastUpdate time, using current time instead");
}
this.lastUpdateTime = new ExpiringCacheEntry(lastModified, this.timeout);
}
return lastModified;
}
/**
* Generate a cache key from a parsed planet request.
* This generates a key of the form ...
*
* <context>/<type>/<language>[/user]
* or
* <context>/<type>[/flavor]/<language>[/excerpts]
*
*
* examples ...
*
* planet/page/en
* planet/feed/rss/en/excerpts
*
*/
public String generateKey(PlanetRequest planetRequest) {
StringBuffer key = new StringBuffer();
key.append(this.CACHE_ID).append(":");
key.append(planetRequest.getContext());
key.append("/");
key.append(planetRequest.getType());
if(planetRequest.getFlavor() != null) {
key.append("/").append(planetRequest.getFlavor());
}
// add language
key.append("/").append(planetRequest.getLanguage());
if(planetRequest.getFlavor() != null) {
// add excerpts
if(planetRequest.isExcerpts()) {
key.append("/excerpts");
}
} else {
// add login state
if(planetRequest.getAuthenticUser() != null) {
key.append("/user=").append(planetRequest.getAuthenticUser());
}
}
return key.toString();
}
}