/*
* @(#)CombiningAlgFactory.java
*
* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
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* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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package com.sun.xacml.combine;
import com.sun.xacml.Constants;
import com.sun.xacml.UnknownIdentifierException;
import java.net.URI;
import java.util.HashMap;
import java.util.Set;
/**
* Provides a factory mechanism for installing and retrieving combining
* algorithms.
*
* @since 1.0
* @author Seth Proctor
*/
public abstract class CombiningAlgFactory
{
// the proxy used to get the default factory
private static CombiningAlgFactoryProxy defaultFactoryProxy;
// the map of registered factories
private static HashMap<String, CombiningAlgFactoryProxy> registeredFactories
= new HashMap<String, CombiningAlgFactoryProxy>();
// <BUG> ignores the configuration, i.e., <combiningAlgFactory useStandardAlgorithms="false">
// /**
// * static intialiazer that sets up the default factory proxy and
// * registers the standard namespaces
// */
// static {
// CombiningAlgFactoryProxy proxy = new CombiningAlgFactoryProxy() {
// public CombiningAlgFactory getFactory() {
// return StandardCombiningAlgFactory.getFactory();
// }
// };
//
// registeredFactories = new HashMap<String, CombiningAlgFactoryProxy>();
// registeredFactories.put(Constants.XACML_1_0_IDENTIFIER, proxy);
// registeredFactories.put(Constants.XACML_2_0_IDENTIFIER, proxy);
// registeredFactories.put(Constants.XACML_3_0_IDENTIFIER, proxy);
//
// defaultFactoryProxy = proxy;
// }
// </BUG>
/**
* Default constructor. Used only by subclasses.
*/
protected CombiningAlgFactory() {
//used only by subclasses
}
/**
* Returns the default factory. Depending on the default factory's
* implementation, this may return a singleton instance or new instances
* with each invokation.
*
* @return the default <code>CombiningAlgFactory</code>
*/
public static final CombiningAlgFactory getInstance() {
return defaultFactoryProxy.getFactory();
}
/**
* Returns a factory based on the given identifier. You may register
* as many factories as you like, and then retrieve them through this
* interface, but a factory may only be registered once using a given
* identifier. By default, the standard XACML 1.0, 2.0 and 3.0 identifiers
* are regsietered to provide the standard factory.
*
* @param identifier the identifier for a factory
*
* @return a <code>CombiningAlgFactory</code>
*
* @throws UnknownIdentifierException if the given identifier isn't
* registered
*/
public static final CombiningAlgFactory getInstance(String identifier)
throws UnknownIdentifierException
{
CombiningAlgFactoryProxy proxy =
(CombiningAlgFactoryProxy)(registeredFactories.get(identifier));
if (proxy == null) {
throw new UnknownIdentifierException("Uknown CombiningAlgFactory "
+ "identifier: " +
identifier);
}
return proxy.getFactory();
}
/**
* Sets the default factory. This does not register the factory proxy as
* an identifiable factory.
*
* @param proxy the <code>CombiningAlgFactoryProxy</code> to set as the
* new default factory proxy
*/
public static final void setDefaultFactory(CombiningAlgFactoryProxy proxy)
{
defaultFactoryProxy = proxy;
}
public static final void setAllFactories(CombiningAlgFactory factory) {
CombiningAlgFactoryProxyImpl proxy = new CombiningAlgFactoryProxyImpl(factory);
registeredFactories.put(Constants.XACML_1_0_IDENTIFIER, proxy);
registeredFactories.put(Constants.XACML_2_0_IDENTIFIER, proxy);
registeredFactories.put(Constants.XACML_3_0_IDENTIFIER, proxy);
defaultFactoryProxy = proxy;
}
/**
* Registers the given factory proxy with the given identifier. If the
* identifier is already used, then this throws an exception. If the
* identifier is not already used, then it will always be bound to the
* given proxy.
*
* @param identifier the identifier for the proxy
* @param proxy the <code>CombiningAlgFactoryProxy</code> to register with
* the given identifier
*
* @throws IllegalArgumentException if the identifier is already used
*/
public static final void registerFactory(String identifier,
CombiningAlgFactoryProxy proxy)
throws IllegalArgumentException
{
synchronized (registeredFactories) {
if (registeredFactories.containsKey(identifier)) {
throw new IllegalArgumentException("Identifier is already " +
"registered as " +
"CombiningAlgFactory: " +
identifier);
}
registeredFactories.put(identifier, proxy);
}
}
/**
* Adds a combining algorithm to the factory. This single instance will
* be returned to anyone who asks the factory for an algorithm with the
* id given here.
*
* @param alg the combining algorithm to add
*
* @throws IllegalArgumentException if the algorithm is already registered
*/
public abstract void addAlgorithm(CombiningAlgorithm alg);
/**
* Adds a combining algorithm to the factory. This single instance will
* be returned to anyone who asks the factory for an algorithm with the
* id given here.
*
* @deprecated As of version 1.2, replaced by
* {@link #addAlgorithm(CombiningAlgorithm)}.
* The new factory system requires you to get a factory
* instance and then call the non-static methods on that
* factory. The static versions of these methods have been
* left in for now, but are slower and will be removed in
* a future version.
*
* @param alg the combining algorithm to add
*
* @throws IllegalArgumentException if the algorithm is already registered
*/
public static void addCombiningAlg(CombiningAlgorithm alg) {
getInstance().addAlgorithm(alg);
}
/**
* Returns the algorithm identifiers supported by this factory.
*
* @return a <code>Set</code> of <code>String</code>s
*/
public abstract Set<String> getSupportedAlgorithms();
/**
* Tries to return the correct combinging algorithm based on the
* given algorithm ID.
*
* @param algId the identifier by which the algorithm is known
*
* @return a combining algorithm
*
* @throws UnknownIdentifierException algId is unknown
*/
public abstract CombiningAlgorithm createAlgorithm(URI algId)
throws UnknownIdentifierException;
/**
* Tries to return the correct combinging algorithm based on the
* given algorithm ID.
*
* @deprecated As of version 1.2, replaced by
* {@link #createAlgorithm(URI)}.
* The new factory system requires you to get a factory
* instance and then call the non-static methods on that
* factory. The static versions of these methods have been
* left in for now, but are slower and will be removed in
* a future version.
*
* @param algId the identifier by which the algorithm is known
*
* @return a combining algorithm
*
* @throws UnknownIdentifierException algId is unknown
*/
public static CombiningAlgorithm createCombiningAlg(URI algId)
throws UnknownIdentifierException
{
return getInstance().createAlgorithm(algId);
}
private static class CombiningAlgFactoryProxyImpl implements CombiningAlgFactoryProxy {
CombiningAlgFactory factory;
CombiningAlgFactoryProxyImpl(CombiningAlgFactory factory) {
this.factory = factory;
}
public CombiningAlgFactory getFactory() {
return factory;
}
}
}