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This is the master POM file for Oracle's Implementation of the JSF 2.0 Specification.
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2011 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.logging.Level;
import java.util.logging.Logger;
import javax.faces.FacesException;
/**
* A concurrent caching mechanism.
*/
public class Cache {
// Log instance for this class
private static final Logger LOGGER = FacesLogger.UTIL.getLogger();
/**
* Factory interface for creating various cacheable objects.
*/
public interface Factory {
V newInstance(final K arg) throws InterruptedException;
} // END Factory
private ConcurrentMap> cache =
new ConcurrentHashMap>();
private Factory factory;
// -------------------------------------------------------- Constructors
/**
* Constructs this cache using the specified Factory.
* @param factory
*/
public Cache(Factory factory) {
this.factory = factory;
}
// ------------------------------------------------------ Public Methods
/**
* If a value isn't associated with the specified key, a new
* {@link java.util.concurrent.Callable} will be created wrapping the Factory
* specified via the constructor and passed to a {@link java.util.concurrent.FutureTask}. This task
* will be passed to the backing ConcurrentMap. When {@link java.util.concurrent.FutureTask#get()}
* is invoked, the Factory will return the new Value which will be cached
* by the {@link java.util.concurrent.FutureTask}.
*
* @param key the key the value is associated with
* @return the value for the specified key, if any
*/
public V get(final K key) {
while (true) {
Future f = cache.get(key);
if (f == null) {
Callable callable = new Callable() {
public V call() throws Exception {
return factory.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();
}
}
try {
return f.get();
} catch (CancellationException ce) {
if (LOGGER.isLoggable(Level.FINEST)) {
LOGGER.log(Level.FINEST,
ce.toString(),
ce);
}
cache.remove(key);
} catch (InterruptedException ie) {
if (LOGGER.isLoggable(Level.FINEST)) {
LOGGER.log(Level.FINEST,
ie.toString(),
ie);
}
cache.remove(key);
} catch (ExecutionException ee) {
throw new FacesException(ee);
}
}
}
public V remove(final K key) {
Future t = cache.remove(key);
V result = null;
if (null != t) {
try {
result = t.get();
} catch (CancellationException ce) {
if (LOGGER.isLoggable(Level.FINEST)) {
LOGGER.log(Level.FINEST,
ce.toString(),
ce);
}
} catch (InterruptedException ie) {
if (LOGGER.isLoggable(Level.FINEST)) {
LOGGER.log(Level.FINEST,
ie.toString(),
ie);
}
} catch (ExecutionException ee) {
throw new FacesException(ee);
}
}
return result;
}
} // END Cache