/*
* @(#)LogicalFunction.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
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* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
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package org.jboss.security.xacml.sunxacml.cond;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.jboss.security.xacml.sunxacml.EvaluationCtx;
import org.jboss.security.xacml.sunxacml.attr.AttributeValue;
import org.jboss.security.xacml.sunxacml.attr.BooleanAttribute;
/**
* A class that implements the logical functions "or" and "and".
* These functions take any number of boolean arguments and evaluate
* them one at a time, starting with the first argument. As soon as
* the result of the function can be determined, evaluation stops and
* that result is returned. During this process, if any argument
* evaluates to indeterminate, an indeterminate result is returned.
*
* @since 1.0
* @author Steve Hanna
* @author Seth Proctor
*/
@SuppressWarnings({"unchecked", "rawtypes"})
public class LogicalFunction extends FunctionBase
{
/**
* Standard identifier for the or function.
*/
public static final String NAME_OR = FUNCTION_NS + "or";
/**
* Standard identifier for the and function.
*/
public static final String NAME_AND = FUNCTION_NS + "and";
// internal identifiers for each of the supported functions
private static final int ID_OR = 0;
private static final int ID_AND = 1;
/**
* Creates a new <code>LogicalFunction</code> object.
*
* @param functionName the standard XACML name of the function to be
* handled by this object, including the full namespace
*
* @throws IllegalArgumentException if the functionName is unknown
*/
public LogicalFunction(String functionName) {
super(functionName, getId(functionName), BooleanAttribute.identifier,
false, -1, BooleanAttribute.identifier, false);
}
/**
* Private helper that looks up the private id based on the function name.
*/
private static int getId(String functionName) {
if (functionName.equals(NAME_OR))
return ID_OR;
else if (functionName.equals(NAME_AND))
return ID_AND;
else
throw new IllegalArgumentException("unknown logical function: " +
functionName);
}
/**
* Returns a <code>Set</code> containing all the function identifiers
* supported by this class.
*
* @return a <code>Set</code> of <code>String</code>s
*/
public static Set getSupportedIdentifiers() {
Set set = new HashSet();
set.add(NAME_OR);
set.add(NAME_AND);
return set;
}
/**
* Evaluate the function, using the specified parameters.
*
* @param inputs a <code>List</code> of <code>Evaluatable</code>
* objects representing the arguments passed to the function
* @param context an <code>EvaluationCtx</code> so that the
* <code>Evaluatable</code> objects can be evaluated
* @return an <code>EvaluationResult</code> representing the
* function's result
*/
public EvaluationResult evaluate(List inputs, EvaluationCtx context) {
// Evaluate the arguments one by one. As soon as we can
// return a result, do so. Return Indeterminate if any argument
// evaluated is indeterminate.
Iterator it = inputs.iterator();
while (it.hasNext()) {
Evaluatable eval = (Evaluatable)(it.next());
// Evaluate the argument
EvaluationResult result = eval.evaluate(context);
if (result.indeterminate())
return result;
AttributeValue value = result.getAttributeValue();
boolean argBooleanValue = ((BooleanAttribute)value).getValue();
switch (getFunctionId()) {
case ID_OR:
if (argBooleanValue)
return EvaluationResult.getTrueInstance();
break;
case ID_AND:
if (!argBooleanValue)
return EvaluationResult.getFalseInstance();
break;
}
}
if (getFunctionId() == ID_OR)
return EvaluationResult.getFalseInstance();
else
return EvaluationResult.getTrueInstance();
}
}