/*
* @(#)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
* 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.net.URI;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.w3c.dom.Node;
import com.sun.xacml.ParsingException;
import com.sun.xacml.UnknownIdentifierException;
/**
* 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
*
* Adding generic type support by Christian Mueller (geotools)
*/
public class BaseFunctionFactory extends FunctionFactory {
// the backing maps for the Function 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) {
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, ? extends 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, ? extends FunctionProxy> supportedAbstractFunctions) {
this(superset);
for (Function function : supportedFunctions)
functionMap.put(function.getIdentifier().toString(), function);
for (URI id : supportedAbstractFunctions.keySet()) {
FunctionProxy proxy = (FunctionProxy) (supportedAbstractFunctions.get(id));
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.
*
* @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 {
String id = function.getIdentifier().toString();
// make sure this doesn't already exist
if (functionMap.containsKey(id))
throw new IllegalArgumentException("function already exists");
// add to the superset factory
if (superset != null)
superset.addFunction(function);
// finally, add to this factory
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 (functionMap.containsKey(id))
throw new IllegalArgumentException("function already exists");
// add to the superset factory
if (superset != null)
superset.addAbstractFunction(proxy, identity);
// finally, add to this factory
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>(functionMap.keySet());
if (superset != null)
set.addAll(superset.getSupportedFunctions());
return set;
}
/**
* 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
*/
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
*/
public Function createFunction(String identity) throws UnknownIdentifierException,
FunctionTypeException {
Object entry = functionMap.get(identity);
if (entry != null) {
if (entry instanceof Function) {
return (Function) entry;
} else {
// this is actually a proxy, which means the other create
// method should have been called
throw new FunctionTypeException("function is abstract");
}
} else {
// 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
* @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
* @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
* @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
*
* @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 = 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);
}
} else {
// this is actually a concrete function, which means that
// the other create method should have been called
throw new FunctionTypeException("function is concrete");
}
} else {
// we couldn't find a match
throw new UnknownIdentifierException("abstract functions of " + "type " + identity
+ " are not supported by " + "this factory");
}
}
}