/*
$Id: SourceCacheImpl.java,v 1.1 2003/11/13 16:07:05 andreas Exp $
<License>
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2003 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 Lenya" 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
Michael Wechner <michi@apache.org>. For more information on the Apache Soft-
ware Foundation, please see <http://www.apache.org/>.
Lenya includes software developed by the Apache Software Foundation, W3C,
DOM4J Project, BitfluxEditor, Xopus, and WebSHPINX.
</License>
*/
package org.apache.lenya.ac.cache;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.SourceNotFoundException;
import org.apache.excalibur.source.SourceResolver;
import org.apache.excalibur.source.SourceValidity;
import org.apache.lenya.util.CacheMap;
/**
* @author andreas
*
* To change the template for this generated type comment go to
* Window - Preferences - Java - Code Generation - Code and Comments
*/
public class SourceCacheImpl
extends AbstractLogEnabled
implements SourceCache, Serviceable, Disposable {
/**
* Returns the service manager.
* @return A service manager.
*/
public ServiceManager getManager() {
return manager;
}
/**
* Returns the source resolver.
* @return A source resolver.
*/
public SourceResolver getResolver() {
return resolver;
}
/**
* Ctor.
*/
public SourceCacheImpl() {
cache = new CacheMap(CAPACITY);
}
public static final int CAPACITY = 1000;
private CacheMap cache;
/**
* Returns the cache.
* @return A cache object.
*/
protected CacheMap getCache() {
return cache;
}
/**
* @see org.apache.lenya.cms.ac2.cache.SourceCache#get(java.lang.String, org.apache.lenya.cms.ac2.cache.InputStreamBuilder)
*/
public Object get(String sourceUri, InputStreamBuilder builder) throws CachingException {
String key = sourceUri;
Object value = null;
CachedObject cachedObject = (CachedObject) getCache().get(key);
boolean usedCache = false;
SourceValidity sourceValidity = null;
try {
if (cachedObject != null) {
getLogger().debug("Found cached object [" + cachedObject + "]");
SourceValidity cachedValidity = cachedObject.getValidityObject();
int result = cachedValidity.isValid();
boolean valid = false;
if (result == 0) {
// get source validity and compare
sourceValidity = getSourceValidity(sourceUri);
if (sourceValidity != null) {
result = cachedValidity.isValid(sourceValidity);
if (result == 0) {
sourceValidity = null;
} else {
valid = (result == 1);
}
}
} else {
valid = (result > 0);
}
if (valid) {
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug(
"Using valid cached source for '" + sourceUri + "'.");
}
usedCache = true;
value = cachedObject.getValue();
} else {
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug(
"Cached content is invalid for '" + sourceUri + "'.");
}
// remove invalid cached object
getCache().remove(key);
}
} else {
getLogger().debug("Did not find cached object.");
}
if (!usedCache) {
getLogger().debug("Did not use cache.");
if (key != null) {
if (sourceValidity == null) {
sourceValidity = getSourceValidity(sourceUri);
}
if (sourceValidity != null) {
getLogger().debug("Source validity is not null.");
} else {
getLogger().debug("Source validity is null - not caching.");
key = null;
}
}
value = buildObject(sourceUri, builder);
// store the response
if (key != null) {
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug(
"Caching object ["
+ value
+ "] for further requests of ["
+ sourceUri
+ "].");
}
getCache().put(key, new CachedObject(sourceValidity, value));
}
}
} catch (Exception e) {
throw new CachingException(e);
}
return value;
}
/**
* Returns the input stream to read a source from.
* @param sourceUri The URI of the source.
* @return An object.
* @throws MalformedURLException when an error occurs.
* @throws IOException when an error occurs.
* @throws SourceNotFoundException when an error occurs.
*/
protected Object buildObject(String sourceUri, InputStreamBuilder builder)
throws MalformedURLException, IOException, SourceNotFoundException, BuildException {
Object value = null;
Source source = null;
try {
source = getResolver().resolveURI(sourceUri);
if (source.exists()) {
InputStream stream = source.getInputStream();
value = builder.build(stream);
}
} finally {
if (source != null) {
getResolver().release(source);
}
}
return value;
}
/**
* Returns the validity of a source.
* @param sourceUri The URI of the source.
* @return A source validity object.
* @throws MalformedURLException when an error occurs.
* @throws IOException when an error occurs.
*/
protected SourceValidity getSourceValidity(String sourceUri)
throws MalformedURLException, IOException {
SourceValidity sourceValidity;
Source source = null;
try {
source = getResolver().resolveURI(sourceUri);
sourceValidity = source.getValidity();
} finally {
if (source != null) {
getResolver().release(source);
}
}
return sourceValidity;
}
private ServiceManager manager;
private SourceResolver resolver;
/**
* @see org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager)
*/
public void service(ServiceManager manager) throws ServiceException {
this.manager = manager;
this.resolver = (SourceResolver) manager.lookup(SourceResolver.ROLE);
}
/**
* @see org.apache.avalon.framework.activity.Disposable#dispose()
*/
public void dispose() {
if (getResolver() != null) {
getManager().release(getResolver());
}
}
}