/*
* @(#)BaseCombiningAlgFactory.java
*
* Copyright 2004 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
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package com.sun.xacml.cond;
import com.sun.xacml.ParsingException;
import com.sun.xacml.UnknownIdentifierException;
import java.net.URI;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.w3c.dom.Node;
/**
* This is a basic implementation of <code>FunctionFactory</code>. It
* implements the insertion and retrieval methods, but it doesn't actually
* setup the factory with any functions. It also assumes a certain model
* with regard to the different kinds of functions (Target, Condition, and
* General). For this reason, you may want to re-use this class, or you
* may want to extend FunctionFactory directly, if you're writing a new
* factory implementation.
* <p>
* Note that while this class is thread-safe on all creation methods, it
* is not safe to add support for a new function while creating an instance
* of a function. This follows from the assumption that most people will
* initialize these factories up-front, and then start processing without
* ever modifying the factories. If you need these mutual operations to
* be thread-safe, then you should write a wrapper class that implements
* the right synchronization.
*
* @since 1.2
* @author Seth Proctor
*/
public class BaseFunctionFactory extends FunctionFactory
{
// the backing maps for the Function objects or FunctionProxy objects
private HashMap<String, Object> functionMap = null;
// the superset factory chained to this factory
private FunctionFactory superset = null;
/**
* Default constructor. No superset factory is used.
*/
public BaseFunctionFactory() {
this(null);
}
/**
* Constructor that sets a "superset factory". This is useful since
* the different function factories (Target, Condition, and General)
* have a superset relationship (Condition functions are a superset
* of Target functions, etc.). Adding a function to this factory will
* automatically add the same function to the superset factory.
*
* @param superset the superset factory or null
*/
public BaseFunctionFactory(FunctionFactory superset) {
this.functionMap = new HashMap<String, Object>();
this.superset = superset;
}
/**
* Constructor that defines the initial functions supported by this
* factory but doesn't use a superset factory.
*
* @param supportedFunctions a <code>Set</code> of <code>Function</code>s
* @param supportedAbstractFunctions a mapping from <code>URI</code> to
* <code>FunctionProxy</code>
*/
public BaseFunctionFactory(Set<Function> supportedFunctions,
Map<URI, FunctionProxy> supportedAbstractFunctions) {
this(null, supportedFunctions, supportedAbstractFunctions);
}
/**
* Constructor that defines the initial functions supported by this
* factory and uses a superset factory. Note that the functions
* supplied here are not propagated up to the superset factory, so
* you must either make sure the superst factory is correctly
* initialized or use <code>BaseFunctionFactory(FunctionFactory)</code>
* and then manually add each function.
*
* @param superset the superset factory or null
* @param supportedFunctions a <code>Set</code> of <code>Function</code>s
* @param supportedAbstractFunctions a mapping from <code>URI</code> to
* <code>FunctionProxy</code>
*/
public BaseFunctionFactory(FunctionFactory superset,
Set<Function> supportedFunctions,
Map<URI, FunctionProxy> supportedAbstractFunctions) {
this(superset);
Iterator<Function> it = supportedFunctions.iterator();
while (it.hasNext()) {
Function function = it.next();
this.functionMap.put(function.getIdentifier().toString(),
function);
}
Iterator<Map.Entry<URI, FunctionProxy>> it2 = supportedAbstractFunctions.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<URI, FunctionProxy> entry = it2.next();
URI id = (URI)(entry.getKey());
FunctionProxy proxy =
(FunctionProxy)(entry.getValue());
this.functionMap.put(id.toString(), proxy);
}
}
/**
* Adds the function to the factory. Most functions have no state, so
* the singleton model used here is typically desireable. The factory will
* not enforce the requirement that a Target or Condition matching function
* must be boolean. If a function is already contained in the factory, an
* error will be thrown.
*
* @param function the <code>Function</code> to add to the factory
*
* @throws IllegalArgumentException if the function's identifier is already
* used or if the function is non-boolean
* (when this is a Target or Condition
* factory)
*/
public void addFunction(Function function)
throws IllegalArgumentException
{
addFunction(function, false);
}
/**
* Adds the function to the factory. Most functions have no state, so
* the singleton model used here is typically desireable. The factory will
* not enforce the requirement that a Target or Condition matching function
* must be boolean.
*
* Allows to define if an already existing function should be overwritten
* or not.
*
* * @param function the <code>Function</code> to add to the factory
*
* @throws IllegalArgumentException if the function's identifier is already
* used or if the function is non-boolean
* (when this is a Target or Condition
* factory)
*/
@Override
public void addFunction(Function function, boolean overwrite)
throws IllegalArgumentException {
String id = function.getIdentifier().toString();
// make sure this doesn't already exist
if (! overwrite && this.functionMap.containsKey(id)) {
throw new IllegalArgumentException("function already exists");
}
// add to the superset factory
if (this.superset != null) {
this.superset.addFunction(function);
}
// finally, add to this factory
this.functionMap.put(id, function);
}
/**
* Adds the abstract function proxy to the factory. This is used for
* those functions which have state, or change behavior (for instance
* the standard map function, which changes its return type based on
* how it is used).
*
* @param proxy the <code>FunctionProxy</code> to add to the factory
* @param identity the function's identifier
*
* @throws IllegalArgumentException if the function's identifier is already
* used
*/
public void addAbstractFunction(FunctionProxy proxy,
URI identity)
throws IllegalArgumentException
{
String id = identity.toString();
// make sure this doesn't already exist
if (this.functionMap.containsKey(id)) {
throw new IllegalArgumentException("function already exists");
}
// add to the superset factory
if (this.superset != null) {
this.superset.addAbstractFunction(proxy, identity);
}
// finally, add to this factory
this.functionMap.put(id, proxy);
}
/**
* Returns the function identifiers supported by this factory.
*
* @return a <code>Set</code> of <code>String</code>s
*/
public Set<String> getSupportedFunctions() {
Set<String> set = new HashSet<String>(this.functionMap.keySet());
if (this.superset != null) {
set.addAll(this.superset.getSupportedFunctions());
}
return set;
}
/**
* Tries to get an instance of the specified function.
*
* @param identity the name of the function
*
* @return The function.
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to an
* abstract function, and should therefore
* be created through createAbstractFunction
*/
public Function createFunction(URI identity)
throws UnknownIdentifierException, FunctionTypeException
{
return createFunction(identity.toString());
}
/**
* Tries to get an instance of the specified function.
*
* @param identity the name of the function
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to an
* abstract function, and should therefore
* be created through createAbstractFunction
*
* @return The function.
*/
public Function createFunction(String identity)
throws UnknownIdentifierException, FunctionTypeException
{
Object entry = this.functionMap.get(identity);
if (entry != null) {
if (entry instanceof Function) {
return (Function)entry;
}
// this is actually a proxy, which means the other create
// method should have been called
throw new FunctionTypeException("function is abstract");
}
// we couldn't find a match
throw new UnknownIdentifierException("functions of type "
+ identity + " are not supported by this factory");
}
/**
* Tries to get an instance of the specified abstract function.
*
* @param identity the name of the function
* @param root the DOM root containing info used to create the function
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to a
* concrete function, and should therefore
* be created through createFunction
*
* @return The function.
*
* @throws ParsingException if the function can't be created with the
* given inputs
*/
public Function createAbstractFunction(URI identity, Node root)
throws UnknownIdentifierException, ParsingException,
FunctionTypeException
{
return createAbstractFunction(identity.toString(), root, null);
}
/**
* Tries to get an instance of the specified abstract function.
*
* @param identity the name of the function
* @param root the DOM root containing info used to create the function
* @param xpathVersion the version specified in the contianing policy, or
* null if no version was specified
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to a
* concrete function, and should therefore
* be created through createFunction
*
* @return The function.
*
* @throws ParsingException if the function can't be created with the
* given inputs
*/
public Function createAbstractFunction(URI identity, Node root,
String xpathVersion)
throws UnknownIdentifierException, ParsingException,
FunctionTypeException
{
return createAbstractFunction(identity.toString(), root, xpathVersion);
}
/**
* Tries to get an instance of the specified abstract function.
*
* @param identity the name of the function
* @param root the DOM root containing info used to create the function
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to a
* concrete function, and should therefore
* be created through createFunction
*
* @return The function.
*
* @throws ParsingException if the function can't be created with the
* given inputs
*/
public Function createAbstractFunction(String identity, Node root)
throws UnknownIdentifierException, ParsingException,
FunctionTypeException
{
return createAbstractFunction(identity, root, null);
}
/**
* Tries to get an instance of the specified abstract function.
*
* @param identity the name of the function
* @param root the DOM root containing info used to create the function
* @param xpathVersion the version specified in the contianing policy, or
* null if no version was specified
*
* @return The function.
*
* @throws UnknownIdentifierException if the name isn't known
* @throws FunctionTypeException if the name is known to map to a
* concrete function, and should therefore
* be created through createFunction
* @throws ParsingException if the function can't be created with the
* given inputs
*/
public Function createAbstractFunction(String identity, Node root,
String xpathVersion)
throws UnknownIdentifierException, ParsingException,
FunctionTypeException {
Object entry = this.functionMap.get(identity);
if (entry != null) {
if (entry instanceof FunctionProxy) {
try {
return ((FunctionProxy)entry).getInstance(root,
xpathVersion);
} catch (Exception e) {
throw new ParsingException("couldn't create abstract" +
" function " + identity, e);
}
}
// this is actually a concrete function, which means that
// the other create method should have been called
throw new FunctionTypeException("function is concrete");
}
// we couldn't find a match
throw new UnknownIdentifierException("abstract functions of " +
"type " + identity +
" are not supported by " +
"this factory");
}
}