/*
* Copyright 1999-2004 The Apache Software Foundation
*
* Licensed 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.
*
*/
/* $Id: SourceCacheImpl.java,v 1.4 2004/04/26 12:07:56 andreas Exp $ */
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;
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.ac.cache.SourceCache#get(java.lang.String, org.apache.lenya.ac.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) {
if (getLogger().isDebugEnabled()){
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) {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Source validity is not null.");
}
} else {
if (getLogger().isDebugEnabled()) {
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.
* @param builder The input stream builder that should be used.
* @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());
}
}
}