/*
* @(#)HigherOrderFunction.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.
*
* 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
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*
* You acknowledge that this software is not designed or intended for use in
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*/
package com.sun.xacml.cond;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Indenter;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.attr.BagAttribute;
import com.sun.xacml.attr.BooleanAttribute;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
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 org.w3c.dom.Document;
import org.w3c.dom.Element;
/**
* Represents all of the higher order bag functions, except map, which has
* its own class due to the issues with its return type. Unlike the other
* functions that are designed to work over any types (the type-* functions)
* these functions don't use specific names to describe what type they
* operate over, so you don't need to install new instances for any new
* datatypes you define.
*
* @since 1.0
* @author Seth Proctor
*/
public class HigherOrderFunction implements Function
{
/**
* Standard identifier for the any-of function.
*/
public static final String NAME_ANY_OF =
FunctionBase.FUNCTION_NS + "any-of";
/**
* Standard identifier for the all-of function.
*/
public static final String NAME_ALL_OF =
FunctionBase.FUNCTION_NS + "all-of";
/**
* Standard identifier for the any-of-any function.
*/
public static final String NAME_ANY_OF_ANY =
FunctionBase.FUNCTION_NS + "any-of-any";
/**
* Standard identifier for the all-of-any function.
*/
public static final String NAME_ALL_OF_ANY =
FunctionBase.FUNCTION_NS + "all-of-any";
/**
* Standard identifier for the any-of-all function.
*/
public static final String NAME_ANY_OF_ALL =
FunctionBase.FUNCTION_NS + "any-of-all";
/**
* Standard identifier for the all-of-all function.
*/
public static final String NAME_ALL_OF_ALL =
FunctionBase.FUNCTION_NS + "all-of-all";
// internal identifiers for each of the supported functions
private static final int ID_ANY_OF = 0;
private static final int ID_ALL_OF = 1;
private static final int ID_ANY_OF_ANY = 2;
private static final int ID_ALL_OF_ANY = 3;
private static final int ID_ANY_OF_ALL = 4;
private static final int ID_ALL_OF_ALL = 5;
// internal mapping of names to ids
private static HashMap idMap;
// the internal identifier for each function
private int functionId;
// the real identifier for each function
private URI identifier;
// should the second argument (the first arg passed to the sub-function)
// be a bag
private boolean secondIsBag;
// the stuff used to make sure that we have a valid return type or a
// known error, just like in the attribute classes
private static URI returnTypeURI;
private static RuntimeException earlyException;
// try to create the return type URI, and also setup the id map
static {
try {
returnTypeURI = new URI(BooleanAttribute.identifier);
} catch (Exception e) {
earlyException = new IllegalArgumentException();
earlyException.initCause(e);
}
idMap = new HashMap();
idMap.put(NAME_ANY_OF, new Integer(ID_ANY_OF));
idMap.put(NAME_ALL_OF, new Integer(ID_ALL_OF));
idMap.put(NAME_ANY_OF_ANY, new Integer(ID_ANY_OF_ANY));
idMap.put(NAME_ALL_OF_ANY, new Integer(ID_ALL_OF_ANY));
idMap.put(NAME_ANY_OF_ALL, new Integer(ID_ANY_OF_ALL));
idMap.put(NAME_ALL_OF_ALL, new Integer(ID_ALL_OF_ALL));
};
/**
* Creates a new instance of the given function.
*
* @param functionName the function to create
*
* @throws IllegalArgumentException if the function is unknown
*/
public HigherOrderFunction(String functionName) {
// try to get the function's identifier
Integer i = (Integer)(idMap.get(functionName));
if (i == null)
throw new IllegalArgumentException("unknown function: " +
functionName);
functionId = i.intValue();
// setup the URI form of this function's idenitity
try {
identifier = new URI(functionName);
} catch (URISyntaxException use) {
throw new IllegalArgumentException("invalid URI");
}
// see if the second arg is a bag
if ((functionId != ID_ANY_OF) && (functionId != ID_ALL_OF))
secondIsBag = true;
else
secondIsBag = false;
}
/**
* 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() {
return Collections.unmodifiableSet(idMap.keySet());
}
/**
* Returns the full identifier of this function, as known by the factories.
*
* @return the function's identifier
*/
public URI getIdentifier() {
return identifier;
}
/**
* Returns the same value as <code>getReturnType</code>. This is here
* to support the <code>Expression</code> interface.
*
* @return the return type
*/
public URI getType() {
return getReturnType();
}
/**
* Returns the type of attribute value that will be returned by
* this function.
*
* @return the return type
*/
public URI getReturnType() {
if (earlyException != null)
throw earlyException;
return returnTypeURI;
}
/**
* Returns whether or not this function will actually return a bag
* of values.
*
* @return true if the function returns a bag of values, otherwise false
*/
public boolean returnsBag() {
return false;
}
/**
* 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 inputs, EvaluationCtx context) {
Iterator iterator = inputs.iterator();
// get the first arg, which is the function
Expression xpr = (Expression)(iterator.next());
Function function = null;
if (xpr instanceof Function) {
function = (Function)xpr;
} else {
function = (Function)(((VariableReference)xpr).
getReferencedDefinition().getExpression());
}
// get the two inputs, and if anything is INDETERMINATE, then we
// stop right away
AttributeValue [] args = new AttributeValue[2];
Evaluatable eval = (Evaluatable)(iterator.next());
EvaluationResult result = eval.evaluate(context);
if (result.indeterminate())
return result;
args[0] = (AttributeValue)(result.getAttributeValue());
eval = (Evaluatable)(iterator.next());
result = eval.evaluate(context);
if (result.indeterminate())
return result;
args[1] = (AttributeValue)(result.getAttributeValue());
// now we're ready to do the evaluation
result = null;
switch(functionId) {
case ID_ANY_OF: {
// param: boolean-function, single value, bag of same type
// return: boolean
// using the function, iterate through the bag, and if one
// of the bag elements matches the single value, return
// true, otherwise return false
result = any(args[0], (BagAttribute)(args[1]), function, context,
false);
break;
}
case ID_ALL_OF: {
// param: boolean-function, single value, bag of same type
// return: boolean
// using the function, iterate through the bag, and if all
// of the bag elements match the single value, return
// true, otherwise return false
result = all(args[0], (BagAttribute)(args[1]), function, context);
break;
}
case ID_ANY_OF_ANY: {
// param: boolean-function, bag, bag of same type
// return: boolean
// apply the function to every combination of a single value from
// the first bag and a single value from the second bag, and if
// any evaluation is true return true, otherwise return false
result = new EvaluationResult(BooleanAttribute.getInstance(false));
Iterator it = ((BagAttribute)args[0]).iterator();
BagAttribute bag = (BagAttribute)(args[1]);
while (it.hasNext()) {
AttributeValue value = (AttributeValue)(it.next());
result = any(value, bag, function, context, false);
if (result.indeterminate())
return result;
if (((BooleanAttribute)(result.
getAttributeValue())).getValue())
break;
}
break;
}
case ID_ALL_OF_ANY: {
// param: boolean-function, bag, bag of same type
// return: boolean
// iterate through the first bag, and if for each of those values
// one of the values in the second bag matches then return true,
// otherwise return false
result = allOfAny((BagAttribute)(args[1]), (BagAttribute)(args[0]),
function, context);
break;
}
case ID_ANY_OF_ALL: {
// param: boolean-function, bag, bag of same type
// return: boolean
// iterate through the second bag, and if for each of those values
// one of the values in the first bag matches then return true,
// otherwise return false
result = anyOfAll((BagAttribute)(args[0]), (BagAttribute)(args[1]),
function, context);
break;
}
case ID_ALL_OF_ALL: {
// param: boolean-function, bag, bag of same type
// return: boolean
// iterate through the first bag, and for each of those values
// if every value in the second bag matches using the given
// function, then return true, otherwise return false
result = new EvaluationResult(BooleanAttribute.getInstance(true));
Iterator it = ((BagAttribute)args[0]).iterator();
BagAttribute bag = (BagAttribute)(args[1]);
while (it.hasNext()) {
AttributeValue value = (AttributeValue)(it.next());
result = all(value, bag, function, context);
if (result.indeterminate())
return result;
if (! ((BooleanAttribute)(result.
getAttributeValue())).getValue())
break;
}
break;
}
}
return result;
}
/**
* Checks that the given inputs are valid for this function.
*
* @param inputs a <code>List</code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException if the inputs are invalid
*/
public void checkInputs(List inputs) throws IllegalArgumentException {
Object [] list = inputs.toArray();
// first off, check that we got the right number of paramaters
if (list.length != 3)
throw new IllegalArgumentException("requires three inputs");
// now, try to cast the first element into a function
Function function = null;
if (list[0] instanceof Function) {
function = (Function)(list[0]);
} else if (list[0] instanceof VariableReference) {
Expression xpr = ((VariableReference)(list[0])).
getReferencedDefinition().getExpression();
if (xpr instanceof Function)
function = (Function)xpr;
}
if (function == null)
throw new IllegalArgumentException("first arg to higher-order " +
" function must be a function");
// check that the function returns a boolean
if (! function.getReturnType().toString().
equals(BooleanAttribute.identifier))
throw new IllegalArgumentException("higher-order function must " +
"use a boolean function");
// get the two inputs
Evaluatable eval1 = (Evaluatable)(list[1]);
Evaluatable eval2 = (Evaluatable)(list[2]);
// the first arg might be a bag
if (secondIsBag && (! eval1.returnsBag()))
throw new IllegalArgumentException("first arg has to be a bag");
// the second arg must be a bag
if (! eval2.returnsBag())
throw new IllegalArgumentException("second arg has to be a bag");
// finally, we need to make sure that the given type will work on
// the given function
List args = new ArrayList();
args.add(eval1);
args.add(eval2);
function.checkInputsNoBag(args);
}
/**
* Checks that the given inputs are valid for this function if all
* inputs are considered to not be bags. This always throws an
* exception, since this function by definition must work on bags.
*
* @param inputs a <code>List</code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException always
*/
public void checkInputsNoBag(List inputs) throws IllegalArgumentException {
throw new IllegalArgumentException("higher-order functions require " +
"use of bags");
}
/**
* Private helper function that performs the any function, but lets you
* swap the argument order (so it can be used by any-of-all)
*/
private EvaluationResult any(AttributeValue value, BagAttribute bag,
Function function, EvaluationCtx context,
boolean argumentsAreSwapped) {
return anyAndAllHelper(value, bag, function, context, false,
argumentsAreSwapped);
}
/**
* Private helper function that performs the all function
*/
private EvaluationResult all(AttributeValue value, BagAttribute bag,
Function function, EvaluationCtx context) {
return anyAndAllHelper(value, bag, function, context, true, false);
}
/**
* Private helper for any & all functions
*/
private EvaluationResult anyAndAllHelper(AttributeValue value,
BagAttribute bag,
Function function,
EvaluationCtx context,
boolean allFunction,
boolean argumentsAreSwapped) {
BooleanAttribute attr = BooleanAttribute.getInstance(allFunction);
Iterator it = bag.iterator();
while (it.hasNext()) {
List params = new ArrayList();
if (! argumentsAreSwapped) {
params.add(value);
params.add((AttributeValue)(it.next()));
} else {
params.add((AttributeValue)(it.next()));
params.add(value);
}
EvaluationResult result = function.evaluate(params, context);
if (result.indeterminate())
return result;
BooleanAttribute bool =
(BooleanAttribute)(result.getAttributeValue());
if (bool.getValue() != allFunction) {
attr = bool;
break;
}
}
return new EvaluationResult(attr);
}
/**
* any-of-all
*/
private EvaluationResult anyOfAll(BagAttribute anyBag, BagAttribute allBag,
Function function,
EvaluationCtx context) {
return allAnyHelper(anyBag, allBag, function, context, true);
}
/**
* all-of-any
*/
private EvaluationResult allOfAny(BagAttribute anyBag, BagAttribute allBag,
Function function,
EvaluationCtx context) {
return allAnyHelper(anyBag, allBag, function, context, false);
}
/**
* Private helper for the all-of-any and any-of-all functions
*/
private EvaluationResult allAnyHelper(BagAttribute anyBag,
BagAttribute allBag,
Function function,
EvaluationCtx context,
boolean argumentsAreSwapped) {
Iterator it = allBag.iterator();
while (it.hasNext()) {
AttributeValue value = (AttributeValue)(it.next());
EvaluationResult result =
any(value, anyBag, function, context, argumentsAreSwapped);
if (result.indeterminate())
return result;
if (! ((BooleanAttribute)(result.
getAttributeValue())).getValue())
return result;
}
return new EvaluationResult(BooleanAttribute.getTrueInstance());
}
/**
* Encodes this <code>HigherOrderFunction</code> into its XML
* representation and writes this encoding to the given
* <code>OutputStream</code> with no indentation.
*
* @param output a stream into which the XML-encoded data is written
*/
public void encode(OutputStream output) {
encode(output, new Indenter(0));
}
/**
* Encodes this <code>HigherOrderFunction</code> into its XML
* representation and writes this encoding to the given
* <code>OutputStream</code> with indentation.
*
* @param output a stream into which the XML-encoded data is written
* @param indenter an object that creates indentation strings
*/
public void encode(OutputStream output, Indenter indenter) {
PrintStream out = new PrintStream(output);
out.println(indenter.makeString() + "<Function FunctionId=\"" +
getIdentifier().toString() + "\"/>");
}
public Element toOWLNode(Document doc) {
Element applyElement = doc.createElement("Function");
//FIXME apply element für OWL
applyElement.setTextContent(getIdentifier().toASCIIString());
return applyElement;
}
public String toProlog() {
//FIXME Prolog
return identifier + "(UNKNOWN_FUNCTION)";
}
}