/*
* @(#)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
* 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.cond;
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.Iterator;
import java.util.List;
import java.util.Set;
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;
/**
* 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
*
* Adding generic type support by Christian Mueller (geotools)
*/
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<String, Integer> 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 final URI returnTypeURI = URI.create(BooleanAttribute.identifier);
// try to create the return type URI, and also setup the id map
static {
idMap = new HashMap<String, Integer>();
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<String> 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() {
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<? extends Expression> inputs, EvaluationCtx context) {
Iterator<? extends Expression> iterator = inputs.iterator();
// get the first arg, which is the function
Expression xpr = 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<AttributeValue> it = ((BagAttribute) args[0]).iterator();
BagAttribute bag = (BagAttribute) (args[1]);
while (it.hasNext()) {
AttributeValue value = 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<AttributeValue> it = ((BagAttribute) args[0]).iterator();
BagAttribute bag = (BagAttribute) (args[1]);
while (it.hasNext()) {
AttributeValue value = 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<? extends Expression> 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<Evaluatable> args = new ArrayList<Evaluatable>();
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<? extends Expression> 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<AttributeValue> it = bag.iterator();
while (it.hasNext()) {
List<AttributeValue> params = new ArrayList<AttributeValue>();
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<AttributeValue> it = allBag.iterator();
while (it.hasNext()) {
AttributeValue value = 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()
+ "\"/>");
}
}