/*
* @(#)BaseAttributeFactory.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:
*
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* 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
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package com.sun.xacml.attr;
import java.net.URI;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
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>AttributeFactory</code>. It implements the insertion and
* retrieval methods, but doesn't actually setup the factory with any datatypes.
* <p>
* Note that while this class is thread-safe on all creation methods, it is not safe to add support
* for a new datatype while creating an instance of a value. 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 BaseAttributeFactory extends AttributeFactory {
// the map of proxies
private HashMap<String, AttributeProxy> attributeMap;
/**
* Default constructor.
*/
public BaseAttributeFactory() {
attributeMap = new HashMap<String, AttributeProxy>();
}
/**
* Constructor that configures this factory with an initial set of supported datatypes.
*
* @param attributes
* a <code>Map</code> of <code>String</code>s to </code>AttributeProxy</code>s
*
* @throws IllegalArgumentException
* if any elements of the Map are not </code>AttributeProxy</code>s
*/
public BaseAttributeFactory(Map<String, AttributeProxy> attributes) {
attributeMap = new HashMap<String, AttributeProxy>();
Iterator<String> it = attributes.keySet().iterator();
while (it.hasNext()) {
try {
String id = it.next();
AttributeProxy proxy = (AttributeProxy) (attributes.get(id));
attributeMap.put(id, proxy);
} catch (ClassCastException cce) {
throw new IllegalArgumentException("an element of the map "
+ "was not an instance of " + "AttributeProxy");
}
}
}
/**
* Adds a proxy to the factory, which in turn will allow new attribute types to be created using
* the factory. Typically the proxy is provided as an anonymous class that simply calls the
* getInstance methods (or something similar) of some <code>AttributeValue</code> class.
*
* @param id
* the name of the attribute type
* @param proxy
* the proxy used to create new attributes of the given type
*/
public void addDatatype(String id, AttributeProxy proxy) {
// make sure this doesn't already exist
if (attributeMap.containsKey(id))
throw new IllegalArgumentException("datatype already exists");
attributeMap.put(id, proxy);
}
/**
* Returns the datatype identifiers supported by this factory.
*
* @return a <code>Set</code> of <code>String</code>s
*/
public Set<String> getSupportedDatatypes() {
return Collections.unmodifiableSet(attributeMap.keySet());
}
/**
* Creates a value based on the given DOM root node. The type of the attribute is assumed to be
* present in the node as an XACML attribute named <code>DataType</code>, as is the case with
* the AttributeValueType in the policy schema. The value is assumed to be the first child of
* this node.
*
* @param root
* the DOM root of an attribute value
*
* @return a new <code>AttributeValue</code>
*
* @throws UnknownIdentifierException
* if the type in the node isn't known to the factory
* @throws ParsingException
* if the node is invalid or can't be parsed by the appropriate proxy
*/
public AttributeValue createValue(Node root) throws UnknownIdentifierException,
ParsingException {
Node node = root.getAttributes().getNamedItem("DataType");
return createValue(root, node.getNodeValue());
}
/**
* Creates a value based on the given DOM root node and data type.
*
* @param root
* the DOM root of an attribute value
* @param dataType
* the type of the attribute
*
* @return a new <code>AttributeValue</code>
*
* @throws UnknownIdentifierException
* if the data type isn't known to the factory
* @throws ParsingException
* if the node is invalid or can't be parsed by the appropriate proxy
*/
public AttributeValue createValue(Node root, URI dataType) throws UnknownIdentifierException,
ParsingException {
return createValue(root, dataType.toString());
}
/**
* Creates a value based on the given DOM root node and data type.
*
* @param root
* the DOM root of an attribute value
* @param type
* the type of the attribute
*
* @return a new <code>AttributeValue</code>
*
* @throws UnknownIdentifierException
* if the type isn't known to the factory
* @throws ParsingException
* if the node is invalid or can't be parsed by the appropriate proxy
*/
public AttributeValue createValue(Node root, String type) throws UnknownIdentifierException,
ParsingException {
AttributeProxy proxy = (AttributeProxy) (attributeMap.get(type));
if (proxy != null) {
try {
return proxy.getInstance(root);
} catch (Exception e) {
throw new ParsingException("couldn't create " + type
+ " attribute based on DOM node");
}
} else {
throw new UnknownIdentifierException("Attributes of type " + type
+ " aren't supported.");
}
}
/**
* Creates a value based on the given data type and text-encoded value. Used primarily by code
* that does an XPath query to get an attribute value, and then needs to turn the resulting
* value into an Attribute class.
*
* @param dataType
* the type of the attribute
* @param value
* the text-encoded representation of an attribute's value
*
* @return a new <code>AttributeValue</code>
*
* @throws UnknownIdentifierException
* if the data type isn't known to the factory
* @throws ParsingException
* if the text is invalid or can't be parsed by the appropriate proxy
*/
public AttributeValue createValue(URI dataType, String value)
throws UnknownIdentifierException, ParsingException {
String type = dataType.toString();
AttributeProxy proxy = (AttributeProxy) (attributeMap.get(type));
if (proxy != null) {
try {
return proxy.getInstance(value);
} catch (Exception e) {
throw new ParsingException("couldn't create " + type + " attribute from input: "
+ value);
}
} else {
throw new UnknownIdentifierException("Attributes of type " + type
+ " aren't supported.");
}
}
}