/*
* @(#)FirstApplicableRuleAlg.java
*
* Copyright 2003-2005 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 org.jboss.security.xacml.sunxacml.combine;
import java.net.URI;
import java.util.Iterator;
import java.util.List;
import org.jboss.security.xacml.sunxacml.EvaluationCtx;
import org.jboss.security.xacml.sunxacml.Rule;
import org.jboss.security.xacml.sunxacml.ctx.Result;
/**
* This is the standard First Applicable rule combining algorithm. It looks
* through the set of rules, finds the first one that applies, and returns
* that evaluation result.
*
* @since 1.0
* @author Seth Proctor
*/
@SuppressWarnings( "rawtypes" )
public class FirstApplicableRuleAlg extends RuleCombiningAlgorithm
{
/**
* The standard URN used to identify this algorithm
*/
public static final String algId =
"urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:" +
"first-applicable";
// a URI form of the identifier
private static URI identifierURI = URI.create(algId);
/**
* Standard constructor.
*/
public FirstApplicableRuleAlg() {
super(identifierURI);
}
/**
* Applies the combining rule to the set of rules based on the
* evaluation context.
*
* @param context the context from the request
* @param parameters a (possibly empty) non-null <code>List</code> of
* <code>CombinerParameter<code>s
* @param ruleElements the rules to combine
*
* @return the result of running the combining algorithm
*/
public Result combine(EvaluationCtx context, List parameters,
List ruleElements) {
Iterator it = ruleElements.iterator();
while (it.hasNext()) {
Rule rule = ((RuleCombinerElement)(it.next())).getRule();
Result result = rule.evaluate(context);
int value = result.getDecision();
// in the case of PERMIT, DENY, or INDETERMINATE, we always
// just return that result, so only on a rule that doesn't
// apply do we keep going...
if (value != Result.DECISION_NOT_APPLICABLE)
return result;
}
// if we got here, then none of the rules applied
return new Result(Result.DECISION_NOT_APPLICABLE,
context.getResourceId().encode());
}
}