/*
* @(#)FunctionBase.java
*
* 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
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* 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
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package com.sun.xacml.cond;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Indenter;
import com.sun.xacml.attr.AttributeDesignator;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.ctx.Status;
/**
* An abstract utility superclass for functions. Supplies several useful
* methods, making it easier to implement a <code>Function</code>. You can
* extend this class or implement <code>Function</code> directly, depending
* on your needs.
*
* @since 1.0
* @author Steve Hanna
* @author Seth Proctor
*/
public abstract class FunctionBase implements Function
{
/**
* The standard namespace where all XACML 1.0 spec-defined functions live
*/
public static final String FUNCTION_NS =
"urn:oasis:names:tc:xacml:1.0:function:";
/**
* The standard namespace where all XACML 2.0 spec-defined functions live
*/
public static final String FUNCTION_NS_2 =
"urn:oasis:names:tc:xacml:2.0:function:";
// A List used by makeProcessingError() to save some steps.
private static List processingErrList = null;
// the name of this function
private String functionName;
// the id used by this function
private int functionId;
// the return type of this function, and whether it's a bag
private String returnType;
private boolean returnsBag;
// flag that tells us which of the two constructors was used
private boolean singleType;
// parameter data if we're only using a single type
private String paramType;
private boolean paramIsBag;
private int numParams;
private int minParams;
// paramater data if we're using different types
private String [] paramTypes;
private boolean [] paramsAreBags;
/**
* Constructor that sets up the function as having some number of
* parameters all of the same given type. If <code>numParams</code> is
* -1, then the length is variable
*
* @param functionName the name of this function as used by the factory
* and any XACML policies
* @param functionId an optional identifier that can be used by your
* code for convenience
* @param paramType the type of all parameters to this function, as used
* by the factory and any XACML documents
* @param paramIsBag whether or not every parameter is actually a bag
* of values
* @param numParams the number of parameters required by this function,
* or -1 if any number are allowed
* @param returnType the type returned by this function, as used by
* the factory and any XACML documents
* @param returnsBag whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String paramType,
boolean paramIsBag, int numParams,
String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = true;
this.paramType = paramType;
this.paramIsBag = paramIsBag;
this.numParams = numParams;
this.minParams = 0;
}
/**
* Constructor that sets up the function as having some number of
* parameters all of the same given type. If <code>numParams</code> is
* -1, then the length is variable, and then <code>minParams</code> may
* be used to specify a minimum number of parameters. If
* <code>numParams</code> is not -1, then <code>minParams</code> is
* ignored.
*
* @param functionName the name of this function as used by the factory
* and any XACML policies
* @param functionId an optional identifier that can be used by your
* code for convenience
* @param paramType the type of all parameters to this function, as used
* by the factory and any XACML documents
* @param paramIsBag whether or not every parameter is actually a bag
* of values
* @param numParams the number of parameters required by this function,
* or -1 if any number are allowed
* @param minParams the minimum number of parameters required if
* <code>numParams</code> is -1
* @param returnType the type returned by this function, as used by
* the factory and any XACML documents
* @param returnsBag whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId, String paramType,
boolean paramIsBag, int numParams, int minParams,
String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = true;
this.paramType = paramType;
this.paramIsBag = paramIsBag;
this.numParams = numParams;
this.minParams = minParams;
}
/**
* Constructor that sets up the function as having different types for
* each given parameter.
*
* @param functionName the name of this function as used by the factory
* and any XACML policies
* @param functionId an optional identifier that can be used by your
* code for convenience
* @param paramTypes the type of each parameter, in order, required by
* this function, as used by the factory and any XACML
* documents
* @param paramIsBag whether or not each parameter is actually a bag
* of values
* @param returnType the type returned by this function, as used by
* the factory and any XACML documents
* @param returnsBag whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId,
String [] paramTypes, boolean [] paramIsBag,
String returnType, boolean returnsBag) {
this(functionName, functionId, returnType, returnsBag);
singleType = false;
this.paramTypes = paramTypes;
this.paramsAreBags = paramIsBag;
}
/**
* Constructor that sets up some basic values for functions that will
* take care of parameter checking on their own. If you use this
* constructor for your function class, then you must override the
* two check methods to make sure that parameters are correct.
*
* @param functionName the name of this function as used by the factory
* and any XACML policies
* @param functionId an optional identifier that can be used by your
* code for convenience
* @param returnType the type returned by this function, as used by
* the factory and any XACML documents
* @param returnsBag whether or not this function returns a bag of values
*/
public FunctionBase(String functionName, int functionId,
String returnType, boolean returnsBag) {
this.functionName = functionName;
this.functionId = functionId;
this.returnType = returnType;
this.returnsBag = returnsBag;
}
/**
* Returns the full identifier of this function, as known by the factories.
*
* @return the function's identifier
*
* @throws IllegalArgumentException if the identifier isn't a valid URI
*/
public URI getIdentifier() {
// this is to get around the exception handling problems, but may
// change if this code changes to include exceptions from the
// constructors
try {
return new URI(functionName);
} catch (URISyntaxException use) {
throw new IllegalArgumentException("invalid URI");
}
}
/**
* Returns the name of the function to be handled by this particular
* object.
*
* @return the function name
*/
public String getFunctionName() {
return functionName;
}
/**
* Returns the Identifier of the function to be handled by this
* particular object.
*
* @return the function Id
*/
public int getFunctionId() {
return functionId;
}
/**
* 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();
}
/**
* Get the attribute type returned by this function.
*
* @return a <code>URI</code> indicating the attribute type
* returned by this function
*/
public URI getReturnType() {
try {
return new URI(returnType);
} catch (Exception e) {
return null;
}
}
/**
* Returns true if this function returns a bag of values.
*
* @return true if the function returns a bag, false otherwise
*/
public boolean returnsBag() {
return returnsBag;
}
/**
* Returns the return type for this particular object.
*
* @return the return type
*/
public String getReturnTypeAsString() {
return returnType;
}
/**
* Create an <code>EvaluationResult</code> that indicates a
* processing error with the specified message. This method
* may be useful to subclasses.
*
* @param message a description of the error
* (<code>null</code> if none)
* @return the desired <code>EvaluationResult</code>
*/
protected static EvaluationResult makeProcessingError(String message) {
// Build up the processing error Status.
if (processingErrList == null) {
String [] errStrings = { Status.STATUS_PROCESSING_ERROR };
processingErrList = Arrays.asList(errStrings);
}
Status errStatus = new Status(processingErrList, message);
EvaluationResult processingError = new EvaluationResult(errStatus);
return processingError;
}
/**
* Evaluates each of the parameters, in order, filling in the argument
* array with the resulting values. If any error occurs, this method
* returns the error, otherwise null is returned, signalling that
* evaluation was successful for all inputs, and the resulting argument
* list can be used.
*
* @param params a <code>List</code> of <code>Evaluatable</code>
* objects representing the parameters to evaluate
* @param context the representation of the request
* @param args an array as long as the params <code>List</code> that
* will, on return, contain the <code>AttributeValue</code>s
* generated from evaluating all parameters
*
* @return <code>null</code> if no errors were encountered, otherwise
* an <code>EvaluationResult</code> representing the error
*/
protected EvaluationResult evalArgs(List params, EvaluationCtx context,
AttributeValue [] args) {
Iterator it = params.iterator();
int index = 0;
while (it.hasNext()) {
// get and evaluate the next parameter
Evaluatable eval = (Evaluatable)(it.next());
EvaluationResult result = eval.evaluate(context);
// If there was an error, pass it back...
if (result.indeterminate())
return result;
// ...otherwise save it and keep going
args[index++] = result.getAttributeValue();
}
// if no error occurred then we got here, so we return no errors
return null;
}
/**
* Default handling of input checking. This does some simple checking
* based on the type of constructor used. If you need anything more
* complex, or if you used the simple constructor, then you must
* override this method.
*
* @param inputs a <code>List></code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException if the inputs won't work
*/
public void checkInputs(List inputs) throws IllegalArgumentException {
// first off, see what kind of function we are
if (singleType) {
// first, check the length of the inputs, if appropriate
if (numParams != -1) {
if (inputs.size() != numParams)
throw new IllegalArgumentException("wrong number of args" +
" to " + functionName);
} else {
if (inputs.size() < minParams)
throw new IllegalArgumentException("not enough args" +
" to " + functionName);
}
// now, make sure everything is of the same, correct type
Iterator it = inputs.iterator();
while (it.hasNext()) {
Evaluatable eval = (Evaluatable)(it.next());
if ((! eval.getType().toString().equals(paramType)) ||
(eval.returnsBag() != paramIsBag))
throw new IllegalArgumentException("illegal parameter");
}
} else {
// first, check the length of the inputs
if (paramTypes.length != inputs.size())
throw new IllegalArgumentException("wrong number of args" +
" to " + functionName);
// now, make sure everything is of the same, correct type
Iterator it = inputs.iterator();
int i = 0;
while (it.hasNext()) {
Evaluatable eval = (Evaluatable)(it.next());
if ((! eval.getType().toString().equals(paramTypes[i])) ||
(eval.returnsBag() != paramsAreBags[i]))
throw new IllegalArgumentException("illegal parameter");
i++;
}
}
}
/**
* Default handling of input checking. This does some simple checking
* based on the type of constructor used. If you need anything more
* complex, or if you used the simple constructor, then you must
* override this method.
*
* @param inputs a <code>List></code> of <code>Evaluatable</code>s
*
* @throws IllegalArgumentException if the inputs won't work
*/
public void checkInputsNoBag(List inputs) throws IllegalArgumentException {
// first off, see what kind of function we are
if (singleType) {
// first check to see if we need bags
if (paramIsBag)
throw new IllegalArgumentException(functionName + "needs" +
"bags on input");
// now check on the length
if (numParams != -1) {
if (inputs.size() != numParams)
throw new IllegalArgumentException("wrong number of args" +
" to " + functionName);
} else {
if (inputs.size() < minParams)
throw new IllegalArgumentException("not enough args" +
" to " + functionName);
}
// finally check param list
Iterator it = inputs.iterator();
while (it.hasNext()) {
Evaluatable eval = (Evaluatable)(it.next());
if (! eval.getType().toString().equals(paramType))
throw new IllegalArgumentException("illegal parameter");
}
} else {
// first, check the length of the inputs
if (paramTypes.length != inputs.size())
throw new IllegalArgumentException("wrong number of args" +
" to " + functionName);
// now, make sure everything is of the same, correct type
Iterator it = inputs.iterator();
int i = 0;
while (it.hasNext()) {
Evaluatable eval = (Evaluatable)(it.next());
if ((! eval.getType().toString().equals(paramTypes[i])) ||
(paramsAreBags[i]))
throw new IllegalArgumentException("illegal parameter");
i++;
}
}
}
/**
* Encodes this <code>FunctionBase</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>FunctionBase</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=\"" +
getFunctionName() + "\"/>");
}
public Element toOWLNode(Document doc) {
Element functionElement = doc.createElement("Function");
functionElement.setTextContent(getFunctionName());
//FIXME OWL für functionElement
return functionElement;
}
public String toProlog() {
return functionName + "(UNKNOWN_FUNCTION)";
}
}