/*
* @(#)AttributeFinder.java
*
* Copyright 2003-2006 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
* 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.finder;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.attr.BagAttribute;
import com.sun.xacml.cond.EvaluationResult;
import java.net.URI;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.w3c.dom.Node;
/**
* This class is used by the PDP to find attribute values that weren't
* originally supplied in the request. It can be called with the data supplied
* in <code>AttributeDesignator<code>s or <code>AttributeSelector</code>s.
* Because the modules in this finder may themselves need attribute data
* to search for attribute data, it's possible that the modules will look
* for values in the <code>EvaluationCtx</code>, which may in turn result
* in the invocation of this finder again, so module writers need to be
* careful about how they build their modules.
* <p>
* Note that unlike the PolicyFinder, this class doesn't always need to
* use every module it has to find a value. The ordering is maintained,
* however, so it will always start with the first module, and proceed
* in order until it finds a value or runs out of modules.
*
* @since 1.0
* @author Seth Proctor
*/
public class AttributeFinder
{
// the list of all modules
private List allModules;
//
private List designatorModules;
//
private List selectorModules;
// the logger we'll use for all messages
private static final Logger logger =
Logger.getLogger(AttributeFinder.class.getName());
/**
* Default constructor.
*/
public AttributeFinder() {
allModules = new ArrayList();
designatorModules = new ArrayList();
selectorModules = new ArrayList();
}
/**
* Returns the ordered <code>List</code> of
* <code>AttributeFinderModule</code>s used by this class to find
* attribute values.
*
* @return a <code>List</code> of <code>AttributeFinderModule</code>s
*/
public List getModules() {
return new ArrayList(allModules);
}
/**
* Sets the ordered <code>List</code> of
* <code>AttributeFinderModule</code>s used by this class to find
* attribute values. The ordering will be maintained.
*
* @param modules a <code>List</code> of
* <code>AttributeFinderModule</code>s
*/
public void setModules(List modules) {
Iterator it = modules.iterator();
allModules = new ArrayList(modules);
designatorModules = new ArrayList();
selectorModules = new ArrayList();
while (it.hasNext()) {
AttributeFinderModule module = (AttributeFinderModule)(it.next());
if (module.isDesignatorSupported())
designatorModules.add(module);
if (module.isSelectorSupported())
selectorModules.add(module);
}
}
/**
* Tries to find attribute values based on the given designator data.
* The result, if successful, will always contain a
* <code>BagAttribute</code>, even if only one value was found. If no
* values were found, but no other error occurred, an empty bag is
* returned.
*
* @param attributeType the datatype of the attributes to find
* @param attributeId the identifier of the attributes to find
* @param issuer the issuer of the attributes, or null if unspecified
* @param subjectCategory the category of the attribute if the
* designatorType is SUBJECT_TARGET, otherwise null
* @param context the representation of the request data
* @param designatorType the type of designator as named by the *_TARGET
* fields in <code>AttributeDesignator</code>
*
* @return the result of attribute retrieval, which will be a bag of
* attributes or an error
*/
public EvaluationResult findAttribute(URI attributeType, URI attributeId,
URI issuer, URI subjectCategory,
EvaluationCtx context,
int designatorType) {
Iterator it = designatorModules.iterator();
// go through each module in order
while (it.hasNext()) {
AttributeFinderModule module = (AttributeFinderModule)(it.next());
// see if the module supports this type
Set types = module.getSupportedDesignatorTypes();
if ((types == null) || (types.
contains(new Integer(designatorType)))) {
// see if the module can find an attribute value
EvaluationResult result =
module.findAttribute(attributeType, attributeId, issuer,
subjectCategory, context,
designatorType);
// if there was an error, we stop right away
if (result.indeterminate()) {
if (logger.isLoggable(Level.INFO))
logger.info("Error while trying to resolve values: " +
result.getStatus().getMessage());
return result;
}
// if the result wasn't empty, then return the result
BagAttribute bag = (BagAttribute)(result.getAttributeValue());
if (! bag.isEmpty())
return result;
}
}
// if we got here then there were no errors but there were also no
// matches, so we have to return an empty bag
if (logger.isLoggable(Level.INFO))
logger.info("Failed to resolve any values for " +
attributeId.toString());
return new EvaluationResult(BagAttribute.
createEmptyBag(attributeType));
}
/**
* Tries to find attribute values based on the given selector data.
* The result, if successful, must always contain a
* <code>BagAttribute</code>, even if only one value was found. If no
* values were found, but no other error occurred, an empty bag is
* returned.
*
* @param contextPath the XPath expression to search against
* @param namespaceNode the DOM node defining namespace mappings to use,
* or null if mappings come from the context root
* @param attributeType the datatype of the attributes to find
* @param context the representation of the request data
* @param xpathVersion the XPath version to use
*
* @return the result of attribute retrieval, which will be a bag of
* attributes or an error
*/
public EvaluationResult findAttribute(String contextPath,
Node namespaceNode,
URI attributeType,
EvaluationCtx context,
String xpathVersion) {
Iterator it = selectorModules.iterator();
// go through each module in order
while (it.hasNext()) {
AttributeFinderModule module = (AttributeFinderModule)(it.next());
// see if the module can find an attribute value
EvaluationResult result =
module.findAttribute(contextPath, namespaceNode, attributeType,
context, xpathVersion);
// if there was an error, we stop right away
if (result.indeterminate()) {
if (logger.isLoggable(Level.INFO))
logger.info("Error while trying to resolve values: " +
result.getStatus().getMessage());
return result;
}
// if the result wasn't empty, then return the result
BagAttribute bag = (BagAttribute)(result.getAttributeValue());
if (! bag.isEmpty())
return result;
}
// if we got here then there were no errors but there were also no
// matches, so we have to return an empty bag
if (logger.isLoggable(Level.INFO))
logger.info("Failed to resolve any values for " + contextPath);
return new EvaluationResult(BagAttribute.
createEmptyBag(attributeType));
}
}