/*
* @(#)MapFunction.java 1.4 01/30/03
*
* 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
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package com.sun.xacml.cond;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Indenter;
import com.sun.xacml.ParsingException;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.attr.BagAttribute;
import com.sun.xacml.ctx.Status;
import java.net.URI;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* Represents the higher order bag function map.
*
* @since 1.0
* @author Seth Proctor
*/
class MapFunction implements Function
{
/**
* The name of this function
*/
public static final String NAME_MAP = FunctionBase.FUNCTION_NS + "map";
// the return type for this instance
private URI returnType;
// the stuff used to make sure that we have a valid identifier or a
// known error, just like in the attribute classes
private static URI identifier;
private static RuntimeException earlyException;
// try to initialize the identifier
static {
try {
identifier = new URI(NAME_MAP);
} catch (Exception e) {
earlyException = new IllegalArgumentException();
earlyException.initCause(e);
}
};
/**
* Creates a new instance of a <code>MapFunction</code>.
*
* @param returnType the type returned by this function
*/
public MapFunction(URI returnType) {
this.returnType = returnType;
}
/**
* 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_MAP);
return set;
}
/**
* Creates a new instance of the map function using the data found in
* the DOM node provided. This is called by a proxy when the factory
* is asked to create one of these functions.
*
* @param root the DOM node of the apply tag containing this function
*
* @return a <code>MapFunction</code> instance
*
* @throws ParsingException if the DOM data was incorrect
*/
public static MapFunction getInstance(Node root) throws ParsingException {
URI returnType = null;
NodeList nodes = root.getChildNodes();
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (node.getNodeName().equals("Function")) {
String funcName = node.getAttributes().
getNamedItem("FunctionId").getNodeValue();
FunctionFactory factory = FunctionFactory.getGeneralInstance();
try {
Function function = factory.createFunction(funcName);
returnType = function.getReturnType();
break;
} catch (FunctionTypeException fte) {
// try to get this as an abstract function
try {
Function function = factory.
createAbstractFunction(funcName, root);
returnType = function.getReturnType();
break;
} catch (Exception e) {
// any exception here is an error
throw new ParsingException("invalid abstract map", e);
}
} catch (Exception e) {
// any exception that's not function type is an error
throw new ParsingException("couldn't parse map body", e);
}
}
}
// see if we found the return type
if (returnType == null)
throw new ParsingException("couldn't find the return type");
return new MapFunction(returnType);
}
/**
* Returns the full identifier of this function, as known by the factories.
*
* @return the function's identifier
*/
public URI getIdentifier() {
// strictly speaking, this should never happen
if (earlyException != null)
throw earlyException;
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 attribute type returned by this function.
*
* @return the return type
*/
public URI getReturnType() {
return returnType;
}
/**
* Returns <code>true</code>, since the map function always returns a bag
*
* @return true
*/
public boolean returnsBag() {
return true;
}
/**
* Helper function to create a processing error message.
*/
private static EvaluationResult makeProcessingError(String message) {
ArrayList code = new ArrayList();
code.add(Status.STATUS_PROCESSING_ERROR);
return new EvaluationResult(new Status(code, message));
}
/**
* Evaluates the function given the input data. Map expects a
* <code>Function</code> followed by a <code>BagAttribute</code>.
*
* @param inputs the input agrument list
* @param context the representation of the request
*
* @return the result of evaluation
*/
public EvaluationResult evaluate(List inputs, EvaluationCtx context) {
// get the inputs, which we expect to be correct
Iterator iterator = inputs.iterator();
Function function = null;
Expression xpr = (Expression)(iterator.next());
if (xpr instanceof Function) {
function = (Function)xpr;
} else {
function = (Function)(((VariableReference)xpr).
getReferencedDefinition().getExpression());
}
Evaluatable eval = (Evaluatable)(iterator.next());
EvaluationResult result = eval.evaluate(context);
// in a higher-order case, if anything is INDETERMINATE, then
// we stop right away
if (result.indeterminate())
return result;
BagAttribute bag = (BagAttribute)(result.getAttributeValue());
// param: function, bag
// return: bag
// for each value in the bag evaluate the given function with
// the value and put the function result in a new bag that
// is ultimately returned
Iterator it = bag.iterator();
List outputs = new ArrayList();
while (it.hasNext()) {
List params = new ArrayList();
params.add(it.next());
result = function.evaluate(params, context);
if (result.indeterminate())
return result;
outputs.add(result.getAttributeValue());
}
return new EvaluationResult(new BagAttribute(returnType, outputs));
}
/**
* Checks that the input list is valid for evaluation.
*
* @param inputs a <code>List</code> of inputs
*
* @throws IllegalArgumentException if the inputs cannot be evaluated
*/
public void checkInputs(List inputs) throws IllegalArgumentException {
Object [] list = inputs.toArray();
// check that we've got the right number of arguments
if (list.length != 2)
throw new IllegalArgumentException("map requires two inputs");
// now check that we've got the right types for map
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 argument to map must " +
"be a Function");
Evaluatable eval = (Evaluatable)(list[1]);
if (! eval.returnsBag())
throw new IllegalArgumentException("second argument to map must " +
"be a bag");
// finally, check that the type in the bag is right for the function
List input = new ArrayList();
input.add(list[1]);
function.checkInputsNoBag(input);
}
/**
* Always throws <code>IllegalArgumentException</code> since map needs
* to work on a bag
*
* @param inputs a <code>List</code> of inputs
*
* @throws IllegalArgumentException always
*/
public void checkInputsNoBag(List inputs) throws IllegalArgumentException {
throw new IllegalArgumentException("map requires a bag");
}
/**
* Encodes this <code>MapFunction</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>MapFunction</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=\"" +
NAME_MAP + "\"/>");
}
public Element toOWLNode(Document doc) {
Element applyElement = doc.createElement("Funtion");
//FIXME apply element für OWL
applyElement.setTextContent(NAME_MAP);
return applyElement;
}
public String toProlog() {
//FIXME Prolog
return identifier + "(UNKNOWN_FUNCTION)";
}
}