/*
* @(#)GeneralSetFunction.java
*
* Copyright 2004-2006 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
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* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
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package com.sun.xacml.cond;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.attr.BagAttribute;
/**
* Specific <code>SetFunction</code> class that supports all of the general-purpose set functions:
* type-intersection and type-union.
*
* @since 1.2
* @author Seth Proctor
*
* Adding generic type support by Christian Mueller (geotools)
*/
public class GeneralSetFunction extends SetFunction {
// private identifiers for the supported functions
private static final int ID_BASE_INTERSECTION = 0;
private static final int ID_BASE_UNION = 1;
// mapping of function name to its associated id and parameter type
private static HashMap<String, Integer> idMap;
private static HashMap<String, String> typeMap;
/**
* Static initializer that sets up the paramater info for all the supported functions.
*/
static {
idMap = new HashMap<String, Integer>();
typeMap = new HashMap<String, String>();
idMap.put(NAME_BASE_INTERSECTION, new Integer(ID_BASE_INTERSECTION));
idMap.put(NAME_BASE_UNION, new Integer(ID_BASE_UNION));
for (int i = 0; i < baseTypes.length; i++) {
String baseName = FUNCTION_NS + simpleTypes[i];
String baseType = baseTypes[i];
idMap.put(baseName + NAME_BASE_INTERSECTION, new Integer(ID_BASE_INTERSECTION));
idMap.put(baseName + NAME_BASE_UNION, new Integer(ID_BASE_UNION));
typeMap.put(baseName + NAME_BASE_INTERSECTION, baseType);
typeMap.put(baseName + NAME_BASE_UNION, baseType);
}
for (int i = 0; i < baseTypes2.length; i++) {
String baseName = FUNCTION_NS_2 + simpleTypes2[i];
String baseType = baseTypes2[i];
idMap.put(baseName + NAME_BASE_INTERSECTION, new Integer(ID_BASE_INTERSECTION));
idMap.put(baseName + NAME_BASE_UNION, new Integer(ID_BASE_UNION));
typeMap.put(baseName + NAME_BASE_INTERSECTION, baseType);
typeMap.put(baseName + NAME_BASE_UNION, baseType);
}
};
/**
* Constructor that is used to create one of the general-purpose standard set functions. The
* name supplied must be one of the standard XACML functions supported by this class, including
* the full namespace, otherwise an exception is thrown. Look in <code>SetFunction</code> for
* details about the supported names.
*
* @param functionName
* the name of the function to create
*
* @throws IllegalArgumentException
* if the function is unknown
*/
public GeneralSetFunction(String functionName) {
super(functionName, getId(functionName), getArgumentType(functionName),
getArgumentType(functionName), true);
}
/**
* Constructor that is used to create instances of general-purpose set functions for new
* (non-standard) datatypes. This is equivalent to using the <code>getInstance</code> methods in
* <code>SetFunction</code> and is generally only used by the run-time configuration code.
*
* @param functionName
* the name of the new function
* @param datatype
* the full identifier for the supported datatype
* @param functionType
* which kind of Set function, based on the <code>NAME_BASE_*</code> fields
*/
public GeneralSetFunction(String functionName, String datatype, String functionType) {
super(functionName, getId(functionType), datatype, datatype, true);
}
/**
* Private helper that returns the internal identifier used for the given standard function.
*/
private static int getId(String functionName) {
Integer id = (Integer) (idMap.get(functionName));
if (id == null)
throw new IllegalArgumentException("unknown set function " + functionName);
return id.intValue();
}
/**
* Private helper that returns the argument type for the given standard function. Note that this
* doesn't check on the return value since the method always is called after getId, so we assume
* that the function is present.
*/
private static String getArgumentType(String functionName) {
return (String) (typeMap.get(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<String> getSupportedIdentifiers() {
return Collections.unmodifiableSet(idMap.keySet());
}
/**
* Evaluates 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<? extends Expression> inputs, EvaluationCtx context) {
// Evaluate the arguments
AttributeValue[] argValues = new AttributeValue[inputs.size()];
EvaluationResult evalResult = evalArgs(inputs, context, argValues);
if (evalResult != null)
return evalResult;
// setup the two bags we'll be using
BagAttribute[] bags = new BagAttribute[2];
bags[0] = (BagAttribute) (argValues[0]);
bags[1] = (BagAttribute) (argValues[1]);
AttributeValue result = null;
Set<AttributeValue> set = new HashSet<AttributeValue>();
switch (getFunctionId()) {
// *-intersection takes two bags of the same type and returns
// a bag of that type
case ID_BASE_INTERSECTION:
// create a bag with the common elements of both inputs, removing
// all duplicate values
Iterator<AttributeValue> it = bags[0].iterator();
// find all the things in bags[0] that are also in bags[1]
while (it.hasNext()) {
AttributeValue value = (AttributeValue) (it.next());
if (bags[1].contains(value)) {
// sets won't allow duplicates, so this addition is ok
set.add(value);
}
}
result = new BagAttribute(bags[0].getType(), set);
break;
// *-union takes two bags of the same type and returns a bag of
// that type
case ID_BASE_UNION:
// create a bag with all the elements from both inputs, removing
// all duplicate values
Iterator<AttributeValue> it0 = bags[0].iterator();
while (it0.hasNext()) {
// first off, add all elements from the first bag...the set
// will ignore all duplicates
set.add(it0.next());
}
Iterator<AttributeValue> it1 = bags[1].iterator();
while (it1.hasNext()) {
// now add all the elements from the second bag...again, all
// duplicates will be ignored by the set
set.add(it1.next());
}
result = new BagAttribute(bags[0].getType(), set);
break;
}
return new EvaluationResult(result);
}
}