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The public API classes of the Apache MyFaces CORE JSF-2.2 project
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package javax.faces;
import javax.faces.application.ApplicationFactory;
import javax.faces.context.FacesContextFactory;
import javax.faces.lifecycle.LifecycleFactory;
import javax.faces.render.RenderKitFactory;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.*;
/**
* see Javadoc of JSF Specification
*
* @author Manfred Geiler (latest modification by $Author: skitching $)
* @version $Revision: 676298 $ $Date: 2008-07-13 05:31:48 -0500 (Sun, 13 Jul 2008) $
*/
public final class FactoryFinder
{
public static final String APPLICATION_FACTORY = "javax.faces.application.ApplicationFactory";
public static final String FACES_CONTEXT_FACTORY = "javax.faces.context.FacesContextFactory";
public static final String LIFECYCLE_FACTORY = "javax.faces.lifecycle.LifecycleFactory";
public static final String RENDER_KIT_FACTORY = "javax.faces.render.RenderKitFactory";
/**
* used as a monitor for itself and _factories.
* Maps in this map are used as monitors for themselves and the corresponding maps in _factories.
*/
private static Map _registeredFactoryNames = new HashMap();
/**
* Maps from classLoader to another map, the container (i.e. Tomcat) will create a class loader for
* each web app that it controls (typically anyway) and that class loader is used as the key.
*
* The secondary map maps the factory name (i.e. FactoryFinder.APPLICATION_FACTORY) to actual instances
* that are created via getFactory. The instances will be of the class specified in the setFactory method
* for the factory name, i.e. FactoryFinder.setFactory(FactoryFinder.APPLICATION_FACTORY, MyFactory.class).
*/
private static Map _factories = new HashMap();
private static final Set VALID_FACTORY_NAMES = new HashSet();
private static final Map ABSTRACT_FACTORY_CLASSES = new HashMap();
static {
VALID_FACTORY_NAMES.add(APPLICATION_FACTORY);
VALID_FACTORY_NAMES.add(FACES_CONTEXT_FACTORY);
VALID_FACTORY_NAMES.add(LIFECYCLE_FACTORY);
VALID_FACTORY_NAMES.add(RENDER_KIT_FACTORY);
ABSTRACT_FACTORY_CLASSES.put(APPLICATION_FACTORY, ApplicationFactory.class);
ABSTRACT_FACTORY_CLASSES.put(FACES_CONTEXT_FACTORY, FacesContextFactory.class);
ABSTRACT_FACTORY_CLASSES.put(LIFECYCLE_FACTORY, LifecycleFactory.class);
ABSTRACT_FACTORY_CLASSES.put(RENDER_KIT_FACTORY, RenderKitFactory.class);
}
// avoid instantiation
FactoryFinder() {
}
public static Object getFactory(String factoryName)
throws FacesException
{
if(factoryName == null)
throw new NullPointerException("factoryName may not be null");
ClassLoader classLoader = getClassLoader();
//This code must be synchronized because this could cause a problem when
//using update feature each time of myfaces (org.apache.myfaces.CONFIG_REFRESH_PERIOD)
//In this moment, a concurrency problem could happen
Map factoryClassNames = null;
Map factoryMap = null;
synchronized(_registeredFactoryNames)
{
factoryClassNames = _registeredFactoryNames.get(classLoader);
if (factoryClassNames == null)
{
String message = "No Factories configured for this Application. This happens if the faces-initialization "+
"does not work at all - make sure that you properly include all configuration settings necessary for a basic faces application " +
"and that all the necessary libs are included. Also check the logging output of your web application and your container for any exceptions!" +
"\nIf you did that and find nothing, the mistake might be due to the fact that you use some special web-containers which "+
"do not support registering context-listeners via TLD files and " +
"a context listener is not setup in your web.xml.\n" +
"A typical config looks like this;\n\n" +
" org.apache.myfaces.webapp.StartupServletContextListener \n" +
" \n";
throw new IllegalStateException(message);
}
if (! factoryClassNames.containsKey(factoryName))
{
throw new IllegalArgumentException("no factory " + factoryName + " configured for this application.");
}
factoryMap = _factories.get(classLoader);
if (factoryMap == null)
{
factoryMap = new HashMap();
_factories.put(classLoader, factoryMap);
}
}
List classNames = null;
Object factory = null;
synchronized (factoryClassNames)
{
factory = factoryMap.get(factoryName);
if (factory != null)
{
return factory;
}
classNames = (List) factoryClassNames.get(factoryName);
}
//release lock while calling out
factory = newFactoryInstance(ABSTRACT_FACTORY_CLASSES.get(factoryName), classNames.iterator(), classLoader);
synchronized (factoryClassNames)
{
//check if someone else already installed the factory
if (factoryMap.get(factoryName) == null)
{
factoryMap.put(factoryName, factory);
}
}
return factory;
}
private static Object newFactoryInstance(Class interfaceClass, Iterator classNamesIterator, ClassLoader classLoader)
{
try
{
Object current = null;
while (classNamesIterator.hasNext())
{
String implClassName = (String) classNamesIterator.next();
Class implClass = classLoader.loadClass(implClassName);
// check, if class is of expected interface type
if (!interfaceClass.isAssignableFrom(implClass))
{
throw new IllegalArgumentException("Class " + implClassName + " is no " + interfaceClass.getName());
}
if (current == null)
{
// nothing to decorate
current = implClass.newInstance();
} else
{
// let's check if class supports the decorator pattern
try
{
Constructor delegationConstructor = implClass.getConstructor(new Class[]{interfaceClass});
// impl class supports decorator pattern,
try
{
// create new decorator wrapping current
current = delegationConstructor.newInstance(new Object[]{current});
} catch (InstantiationException e)
{
throw new FacesException(e);
} catch (IllegalAccessException e)
{
throw new FacesException(e);
} catch (InvocationTargetException e)
{
throw new FacesException(e);
}
} catch (NoSuchMethodException e)
{
// no decorator pattern support
current = implClass.newInstance();
}
}
}
return current;
} catch (ClassNotFoundException e)
{
throw new FacesException(e);
} catch (InstantiationException e)
{
throw new FacesException(e);
} catch (IllegalAccessException e)
{
throw new FacesException(e);
}
}
public static void setFactory(String factoryName,
String implName)
{
checkFactoryName(factoryName);
ClassLoader classLoader = getClassLoader();
Map factoryClassNames = null;
synchronized(_registeredFactoryNames)
{
Map factories = _factories.get(classLoader);
if (factories != null && factories.containsKey(factoryName)) {
// Javadoc says ... This method has no effect if getFactory() has already been
// called looking for a factory for this factoryName.
return;
}
factoryClassNames = _registeredFactoryNames.get(classLoader);
if (factoryClassNames == null)
{
factoryClassNames = new HashMap();
_registeredFactoryNames.put(classLoader, factoryClassNames);
}
}
synchronized (factoryClassNames)
{
List classNameList = factoryClassNames.get(factoryName);
if (classNameList == null)
{
classNameList = new ArrayList();
factoryClassNames.put(factoryName, classNameList);
}
classNameList.add(implName);
}
}
public static void releaseFactories()
throws FacesException
{
ClassLoader classLoader = getClassLoader();
//This code must be synchronized
synchronized(_registeredFactoryNames)
{
_factories.remove(classLoader);
// _registeredFactoryNames has as value type Map and this must
//be cleaned before release (for gc).
Map factoryClassNames = (Map) _registeredFactoryNames.get(classLoader);
if (factoryClassNames != null) factoryClassNames.clear();
_registeredFactoryNames.remove(classLoader);
}
}
private static void checkFactoryName(String factoryName)
{
if (! VALID_FACTORY_NAMES.contains(factoryName))
{
throw new IllegalArgumentException("factoryName '" + factoryName + "'");
}
}
private static ClassLoader getClassLoader()
{
try
{
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
if (classLoader == null)
{
throw new FacesException("web application class loader cannot be identified", null);
}
return classLoader;
}
catch (Exception e)
{
throw new FacesException("web application class loader cannot be identified", e);
}
}
}
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