/*
* @(#)GeneralBagFunction.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
* notice, this list of conditions and the following disclaimer in the
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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
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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package com.sun.xacml.cond;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
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;
import com.sun.xacml.attr.IntegerAttribute;
/**
* Specific <code>BagFunction</code> class that supports all of the general-purpose bag functions:
* type-one-and-only, type-bag-size, and type-bag.
*
* @since 1.2
* @author Seth Proctor
*
* Adding generic type support by Christian Mueller (geotools)
*/
public class GeneralBagFunction extends BagFunction {
// private identifiers for the supported functions
private static final int ID_BASE_ONE_AND_ONLY = 0;
private static final int ID_BASE_BAG_SIZE = 1;
private static final int ID_BASE_BAG = 2;
// mapping of function name to its associated parameters
private static HashMap<String, BagParameters> paramMap;
private static Set<String> supportedIds;
/**
* Static initializer that sets up the paramater info for all the supported functions.
*/
static {
paramMap = new HashMap<String, BagParameters>();
for (int i = 0; i < baseTypes.length; i++) {
String baseType = baseTypes[i];
String functionBaseName = FUNCTION_NS + simpleTypes[i];
paramMap.put(functionBaseName + NAME_BASE_ONE_AND_ONLY, new BagParameters(
ID_BASE_ONE_AND_ONLY, baseType, true, 1, baseType, false));
paramMap.put(functionBaseName + NAME_BASE_BAG_SIZE, new BagParameters(ID_BASE_BAG_SIZE,
baseType, true, 1, IntegerAttribute.identifier, false));
paramMap.put(functionBaseName + NAME_BASE_BAG, new BagParameters(ID_BASE_BAG, baseType,
false, -1, baseType, true));
}
for (int i = 0; i < baseTypes2.length; i++) {
String baseType = baseTypes2[i];
String functionBaseName = FUNCTION_NS_2 + simpleTypes2[i];
paramMap.put(functionBaseName + NAME_BASE_ONE_AND_ONLY, new BagParameters(
ID_BASE_ONE_AND_ONLY, baseType, true, 1, baseType, false));
paramMap.put(functionBaseName + NAME_BASE_BAG_SIZE, new BagParameters(ID_BASE_BAG_SIZE,
baseType, true, 1, IntegerAttribute.identifier, false));
paramMap.put(functionBaseName + NAME_BASE_BAG, new BagParameters(ID_BASE_BAG, baseType,
false, -1, baseType, true));
}
supportedIds = Collections.unmodifiableSet(new HashSet<String>(paramMap.keySet()));
paramMap.put(NAME_BASE_ONE_AND_ONLY, new BagParameters(ID_BASE_ONE_AND_ONLY, null, true, 1,
null, false));
paramMap.put(NAME_BASE_BAG_SIZE, new BagParameters(ID_BASE_BAG_SIZE, null, true, 1,
IntegerAttribute.identifier, false));
paramMap.put(NAME_BASE_BAG, new BagParameters(ID_BASE_BAG, null, false, -1, null, true));
};
/**
* Constructor that is used to create one of the general-purpose standard bag 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>BagFunction</code> for
* details about the supported names.
*
* @param functionName
* the name of the function to create
*
* @throws IllegalArgumentException
* if the function is unknown
*/
public GeneralBagFunction(String functionName) {
super(functionName, getId(functionName), getArgumentType(functionName),
getIsBag(functionName), getNumArgs(functionName), getReturnType(functionName),
getReturnsBag(functionName));
}
/**
* Constructor that is used to create instances of general-purpose bag functions for new
* (non-standard) datatypes. This is equivalent to using the <code>getInstance</code> methods in
* <code>BagFunction</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 Bag function, based on the <code>NAME_BASE_*</code> fields
*/
public GeneralBagFunction(String functionName, String datatype, String functionType) {
super(functionName, getId(functionType), datatype, getIsBag(functionType),
getNumArgs(functionType), getCustomReturnType(functionType, datatype),
getReturnsBag(functionType));
}
/**
* Private helper that returns the internal identifier used for the given standard function.
*/
private static int getId(String functionName) {
BagParameters params = (BagParameters) (paramMap.get(functionName));
if (params == null)
throw new IllegalArgumentException("unknown bag function: " + functionName);
return params.id;
}
/**
* 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 ((BagParameters) (paramMap.get(functionName))).arg;
}
/**
* Private helper that returns if the given standard function takes a bag. 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 boolean getIsBag(String functionName) {
return ((BagParameters) (paramMap.get(functionName))).argIsBag;
}
/**
* Private helper that returns the argument count 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 int getNumArgs(String functionName) {
return ((BagParameters) (paramMap.get(functionName))).params;
}
/**
* Private helper that returns the return 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 getReturnType(String functionName) {
return ((BagParameters) (paramMap.get(functionName))).returnType;
}
/**
* Private helper that returns if the return type is a bag 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 boolean getReturnsBag(String functionName) {
return ((BagParameters) (paramMap.get(functionName))).returnsBag;
}
/**
* Private helper used by the custom datatype constructor to figure out what the return type is.
* 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 getCustomReturnType(String functionType, String datatype) {
String ret = ((BagParameters) (paramMap.get(functionType))).returnType;
if (ret == null)
return datatype;
else
return ret;
}
/**
* 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 supportedIds;
}
/**
* Evaluate 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 result = evalArgs(inputs, context, argValues);
if (result != null)
return result;
// Now that we have real values, perform the requested operation.
AttributeValue attrResult = null;
switch (getFunctionId()) {
// *-one-and-only takes a single bag and returns a
// single value of baseType
case ID_BASE_ONE_AND_ONLY: {
BagAttribute bag = (BagAttribute) (argValues[0]);
if (bag.size() != 1)
return makeProcessingError(getFunctionName() + " expects "
+ "a bag that contains a single " + "element, got a bag with " + bag.size()
+ " elements");
attrResult = (AttributeValue) (bag.iterator().next());
break;
}
// *-size takes a single bag and returns an integer
case ID_BASE_BAG_SIZE: {
BagAttribute bag = (BagAttribute) (argValues[0]);
attrResult = new IntegerAttribute(bag.size());
break;
}
// *-bag takes any number of elements of baseType and
// returns a bag containing those elements
case ID_BASE_BAG: {
List<AttributeValue> argsList = Arrays.asList(argValues);
attrResult = new BagAttribute(getReturnType(), argsList);
break;
}
}
return new EvaluationResult(attrResult);
}
/**
* Private class that is used for mapping each function to it set of parameters.
*/
private static class BagParameters {
public int id;
public String arg;
public boolean argIsBag;
public int params;
public String returnType;
public boolean returnsBag;
public BagParameters(int id, String arg, boolean argIsBag, int params, String returnType,
boolean returnsBag) {
this.id = id;
this.arg = arg;
this.argIsBag = argIsBag;
this.params = params;
this.returnType = returnType;
this.returnsBag = returnsBag;
}
}
}