/*
* @(#)PolicyCombiningAlgorithm.java
*
* Copyright 2003-2004 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.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* 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
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed or intended for use in
* the design, construction, operation or maintenance of any nuclear facility.
*/
package com.sun.xacml.combine;
import java.net.URI;
import java.util.List;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.ctx.Result;
/**
* The base type for all Policy combining algorithms. Unlike in Rule Combining Algorithms, each
* policy must be matched before they're evaluated to make sure they apply. Also, in combining
* policies, obligations must be handled correctly. Specifically, no obligation may be included in
* the <code>Result</code> that doesn't match the effect being returned. So, if INDETERMINATE or
* NOT_APPLICABLE is the returned effect, no obligations may be included in the result. If the
* effect of the combining algorithm is PERMIT or DENY, then obligations with a matching fulfillOn
* effect are also included in the result.
*
* @since 1.0
* @author Seth Proctor
* @author Marco Barreno
*/
public abstract class PolicyCombiningAlgorithm extends CombiningAlgorithm {
/**
* Constructor that takes the algorithm's identifier.
*
* @param identifier
* the algorithm's identifier
*/
public PolicyCombiningAlgorithm(URI identifier) {
super(identifier);
}
/**
* Combines the policies based on the context to produce some unified result. This is the one
* function of a combining algorithm.
* <p>
* Note that unlike in the RuleCombiningAlgorithms, here you must explicitly match the
* sub-policies to make sure that you should consider them, and you must handle Obligations.
*
* @param context
* the representation of the request
* @param parameters
* a (possibly empty) non-null <code>List</code> of <code>CombinerParameter<code>s
* @param policyElements
* a <code>List</code> of <code>CombinerElement<code>s
*
* @return a single unified result based on the combining logic
*/
public abstract Result combine(EvaluationCtx context, List<CombinerParameter> parameters,
List<? extends CombinerElement> policyElements);
}