/*
* @(#)AttributeFinderModule.java
*
* Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
*
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* modification, are permitted provided that the following conditions are met:
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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.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.Set;
import org.w3c.dom.Node;
/**
* This is the abstract class that all <code>AttributeFinder</code> modules
* extend. All methods have default values to represent that the given
* feature isn't supported by this module, so module writers needs only
* implement the methods for the features they're supporting.
*
* @since 1.0
* @author Seth Proctor
* @author Ludwig Seitz
*/
public abstract class AttributeFinderModule
{
/**
* Returns this module's identifier. A module does not need to provide
* a unique identifier, but it is a good idea, especially in support of
* management software. Common identifiers would be the full package
* and class name (the default if this method isn't overridden), just the
* class name, or some other well-known string that identifies this class.
*
* @return this module's identifier
*/
public String getIdentifier() {
return getClass().getName();
}
/**
* Returns true if this module supports retrieving attributes based on the
* data provided in an AttributeDesignatorType. By default this method
* returns false.
*
* @return true if retrieval based on designator data is supported
*/
public boolean isDesignatorSupported() {
return false;
}
/**
* Returns true if this module supports retrieving attributes based on the
* data provided in an AttributeSelectorType. By default this method
* returns false.
*
* @return true if retrieval based on selector data is supported
*/
public boolean isSelectorSupported() {
return false;
}
/**
* Returns a <code>Set</code> of <code>Integer</code>s that represent
* which AttributeDesignator types are supported (eg, Subject, Resource,
* etc.), or null meaning that no particular types are supported. A
* return value of null can mean that this module doesn't support
* designator retrieval, or that it supports designators of all types.
* If the set is non-null, it should contain the values specified in
* the <code>AttributeDesignator</code> *_TARGET fields.
*
* @return a <code>Set</code> of <code>Integer</code>s, or null
*/
public Set<Integer> getSupportedDesignatorTypes() {
return null;
}
/**
* Returns a <code>Set</code> of <code>URI</code>s that represent the
* attributeIds handled by this module, or null if this module doesn't
* handle any specific attributeIds. A return value of null means that
* this module will try to resolve attributes of any id.
*
* @return a <code>Set</code> of <code>URI</code>s, or null
*/
public Set<URI> getSupportedIds() {
return null;
}
/**
* This is an experimental method that asks the module to invalidate any
* cache values it may contain. This is not used by any of the core
* processing code, but it may be used by management software that wants
* to have some control over these modules. Since a module is free to
* decide how or if it caches values, and whether it is capable of
* updating values once in a cache, a module is free to intrepret this
* message in any way it sees fit (including igoring the message). It
* is preferable, however, for a module to make every effort to clear
* any dynamically cached values it contains.
* <p>
* This method has been introduced to see what people think of this
* functionality, and how they would like to use it. It may be removed
* in future versions, or it may be changed to a more general
* message-passing system (if other useful messages are identified).
*
* @since 1.2
*/
public void invalidateCache() {
//not defined yet, for future extensions
}
/**
* Tries to find attribute values based on the given designator 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. This method may need to invoke the context data to look
* for other attribute values, so a module writer must take care not
* to create a scenario that loops forever.
*
* @param category the category of the attribute
* @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 context the representation of the request data
*
* @return the result of attribute retrieval, which will be a bag of
* attributes or an error
*/
public EvaluationResult findAttribute(URI category, URI attributeType,
URI attributeId, URI issuer,
EvaluationCtx context) {
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. This method may need to invoke the context data to look
* for other attribute values, so a module writer must take care not
* to create a scenario that loops forever.
*
* @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) {
return new EvaluationResult(BagAttribute.
createEmptyBag(attributeType));
}
}