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This is the master POM file for Oracle's Implementation of the JSF 2.2 Specification.
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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.faces.util;
import java.util.concurrent.Callable;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.faces.FacesException;
/**
* This class implements an abstract ConcurrentCache with objects in the cache potentially expiring.
* Only non-expired objects will be returned from the cache or considered to be contained in the cache
* The cache is self-managing, so no remove() method is defined
*/
public final class ExpiringConcurrentCache extends ConcurrentCache {
/**
* Interface for checking whether a cached object expired
*/
public interface ExpiryChecker{
/**
* Checks whether a cached object expired
* @param key cache key
* @param value cached value
* @return true if the value expired and should be removed from the cache, false otherwise
*/
public boolean isExpired(K key, V value);
}
/**
* Public constructor.
* @param f used to create new instances of objects that are not already available
* @param checker used to check whether an object in the cache has expired
*/
public ExpiringConcurrentCache(Factory f, ExpiryChecker checker) {
super(f);
_checker = checker;
}
@Override
public V get(final K key) throws ExecutionException {
// This method uses a design pattern from "Java concurrency in practice".
// The pattern ensures that only one thread gets to create an object missing in the cache,
// while the all the other threads tring to get it are waiting
while (true) {
boolean newlyCached = false;
Future f = _cache.get(key);
if (f == null) {
Callable callable = new Callable() {
public V call() throws Exception {
return getFactory().newInstance(key);
}
};
FutureTask ft = new FutureTask(callable);
// here is the real beauty of the concurrent utilities.
// 1. putIfAbsent() is atomic
// 2. putIfAbsent() will return the value already associated
// with the specified key
// So, if multiple threads make it to this point
// they will all be calling f.get() on the same
// FutureTask instance, so this guarantees that the instances
// that the invoked Callable will return will be created once
f = _cache.putIfAbsent(key, ft);
if (f == null) {
f = ft;
ft.run();
newlyCached = true;
}
}
try {
V obj = f.get();
if (!newlyCached && _getExpiryChecker().isExpired(key, obj)) {
// Note that we are using both key and value in remove() call to ensure
// that we are not removing the Future added after expiry check by a different thread
_cache.remove(key, f);
}
else {
return obj;
}
} catch (CancellationException ce) {
if (_LOGGER.isLoggable(Level.SEVERE)) {
_LOGGER.log(Level.SEVERE,
ce.toString(),
ce);
}
_cache.remove(key, f);
} catch (ExecutionException ee) {
_cache.remove(key, f);
throw ee;
} catch (InterruptedException ie) {
throw new FacesException(ie);
}
}
}
@Override
public boolean containsKey(final K key) {
Future f = _cache.get(key);
if (f != null && f.isDone() && !f.isCancelled()) {
try {
// Call get() with a 0 timeout to avoid any wait
V obj = f.get(0, TimeUnit.MILLISECONDS);
if (_getExpiryChecker().isExpired(key, obj)) {
// Note that we are using both key and value in remove() call to ensure
// that we are not removing the Future added after expiry check by a different thread
_cache.remove(key, f);
} else {
return true;
}
} catch (TimeoutException ce) {
// do nothing. This just indicates that the object is not yet ready
} catch (CancellationException ce) {
if (_LOGGER.isLoggable(Level.SEVERE)) {
_LOGGER.log(Level.SEVERE, ce.toString(), ce);
}
} catch (InterruptedException ie) {
throw new FacesException(ie);
} catch (ExecutionException ee) {
// Do nothing - the FutureTask will be removed by the thread that called get() on this class
}
}
return false;
}
private ExpiryChecker _getExpiryChecker() {
return _checker;
}
private final ExpiryChecker _checker;
private final ConcurrentMap> _cache = new ConcurrentHashMap>();
private static final Logger _LOGGER = FacesLogger.UTIL.getLogger();
}