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Jetty web application support
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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.ee8.webapp;
import java.io.IOException;
import java.net.URL;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.annotation.ManagedOperation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A WebAppClassLoader that caches {@link #getResource(String)} results.
* Specifically this ClassLoader caches not found classes and resources,
* which can greatly increase performance for applications that search
* for resources.
*/
@ManagedObject
public class CachingWebAppClassLoader extends WebAppClassLoader {
private static final Logger LOG = LoggerFactory.getLogger(CachingWebAppClassLoader.class);
private final Set _notFound = ConcurrentHashMap.newKeySet();
private final ConcurrentHashMap _cache = new ConcurrentHashMap<>();
public CachingWebAppClassLoader(ClassLoader parent, Context context) throws IOException {
super(parent, context);
}
public CachingWebAppClassLoader(Context context) throws IOException {
super(context);
}
@Override
public URL getResource(String name) {
if (_notFound.contains(name)) {
if (LOG.isDebugEnabled())
LOG.debug("Not found cache hit resource {}", name);
return null;
}
URL url = _cache.get(name);
if (url == null) {
// Not found in cache, try parent
url = super.getResource(name);
if (url == null) {
// Still not found, cache the not-found result
if (LOG.isDebugEnabled())
LOG.debug("Caching not found resource {}", name);
_notFound.add(name);
} else {
// Cache the new result
_cache.putIfAbsent(name, url);
}
}
return url;
}
@Override
public Class> loadClass(String name) throws ClassNotFoundException {
if (_notFound.contains(name)) {
if (LOG.isDebugEnabled())
LOG.debug("Not found cache hit resource {}", name);
throw new ClassNotFoundException(name + ": in notfound cache");
}
try {
return super.loadClass(name);
} catch (ClassNotFoundException nfe) {
if (_notFound.add(name))
if (LOG.isDebugEnabled()) {
LOG.debug("Caching not found {}", name, nfe);
}
throw nfe;
}
}
@ManagedOperation
public void clearCache() {
_cache.clear();
_notFound.clear();
}
@Override
public String toString() {
return "Caching[" + super.toString() + "]";
}
}