org.wso2.balana.finder.impl

Class SelectorModule

java.lang.Object

org.wso2.balana.finder.AttributeFinderModule

org.wso2.balana.finder.impl.SelectorModule

public class SelectorModule
extends AttributeFinderModule

This module implements the basic behavior of the AttributeSelectorType, looking for attribute values in the physical request document using the given XPath expression. This is implemented as a separate module (instead of being implemented directly in AttributeSelector so that programmers can remove this functionality if they want (it's optional in the spec), so they can replace this code with more efficient, specific code as needed, and so they can easily swap in different XPath libraries.

Note that if no matches are found, this module will return an empty bag (unless some error occurred). The AttributeSelector is still deciding what to return to the policy based on the MustBePresent attribute.

This module uses the Xalan XPath implementation, and supports only version 1.0 of XPath. It is a fully functional, correct implementation of XACML's AttributeSelector functionality, but is not designed for environments that make significant use of XPath queries. Developers for any such environment should consider implementing their own module.

Since:

1.0

Author:

Seth Proctor

Constructor Summary

Constructors

Constructor and Description
SelectorModule()

Method Summary

Modifier and Type	Method and Description
EvaluationResult	findAttribute(String contextPath, URI attributeType, String contextSelector, Node root, EvaluationCtx context, String xpathVersion) Tries to find attribute values based on the given selector data.
boolean	isSelectorSupported() Returns true since this module supports retrieving attributes based on the data provided in an AttributeSelectorType.

Methods inherited from class org.wso2.balana.finder.AttributeFinderModule

findAttribute, getIdentifier, getSupportedCategories, getSupportedIds, invalidateCache, isDesignatorSupported

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SelectorModule

public SelectorModule()

Method Detail

isSelectorSupported

public boolean isSelectorSupported()

Returns true since this module supports retrieving attributes based on the data provided in an AttributeSelectorType.

Overrides:

isSelectorSupported in class AttributeFinderModule

Returns:

true

findAttribute

public EvaluationResult findAttribute(String contextPath,
                                      URI attributeType,
                                      String contextSelector,
                                      Node root,
                                      EvaluationCtx context,
                                      String xpathVersion)

Description copied from class: AttributeFinderModule

Tries to find attribute values based on the given selector data. The result, if successful, must always contain a BagAttribute, 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.

Overrides:

findAttribute in class AttributeFinderModule

Parameters:

contextPath - the XPath expression to search against

attributeType - the datatype of the attributes to find

contextSelector - the selector to find the context to apply XPath expression if this is null, applied for default content. This is only used with XACML 3.0

root - the DOM node that XPath evaluation is done. this only used by XACML 3.0 this can be null, if other XACML versions are used.

context - the representation of the request data

xpathVersion - the XPath version to use

Returns:

the result of attribute retrieval, which will be a bag of attributes or an error