com.sun.xacml.attr
Class AttributeSelector

java.lang.Object
  com.sun.xacml.attr.AttributeSelector

All Implemented Interfaces:

Evaluatable

public class AttributeSelector

extends Object

implements Evaluatable

Supports the standard selector functionality in XACML, which uses XPath expressions to resolve values from the Request or elsewhere. All selector queries are done by AttributeFinderModules so that it's easy to plugin different XPath implementations.

Since:

1.0

Constructor Summary

AttributeSelector(URI type, String contextPath, boolean mustBePresent, String xpathVersion)
Creates a new AttributeSelector with no policy root.

AttributeSelector(URI type, String contextPath, Node policyRoot, boolean mustBePresent, String xpathVersion)
Creates a new AttributeSelector.

Method Summary

void	encode(OutputStream output) Encodes this selector into its XML representation and writes this encoding to the given OutputStream with no indentation.
void	encode(OutputStream output, Indenter indenter) Encodes this selector into its XML representation and writes this encoding to the given OutputStream with indentation.
EvaluationResult	evaluate(EvaluationCtx context) Invokes the AttributeFinder used by the given EvaluationCtx to try to resolve an attribute value.
boolean	evaluatesToBag() Always returns true, since a selector always returns a bag of attribute values.
List	getChildren() Always returns an empty list since selectors never have children.
String	getContextPath() Returns the XPath query used to resolve attribute values.
static AttributeSelector	getInstance(Node root, String xpathVersion) Creates a new AttributeSelector based on the DOM root of the XML type.
URI	getType() Returns the data type of the attribute values that this selector will resolve
String	getXPathVersion() Returns the XPath version this selector is supposed to use.
boolean	mustBePresent() Returns whether or not a value is required to be resolved by this selector.

Methods inherited from class java.lang.Object

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

Constructor Detail

AttributeSelector

public AttributeSelector(URI type,
                         String contextPath,
                         boolean mustBePresent,
                         String xpathVersion)

Creates a new AttributeSelector with no policy root.

Parameters:

type - the data type of the attribute values this selector looks for

contextPath - the XPath to query

mustBePresent - must resolution find a match

xpathVersion - the XPath version to use, which must be a valid XPath version string (the identifier for XPath 1.0 is provided in AbstractPolicy)

AttributeSelector

public AttributeSelector(URI type,
                         String contextPath,
                         Node policyRoot,
                         boolean mustBePresent,
                         String xpathVersion)

Creates a new AttributeSelector.

Parameters:

type - the data type of the attribute values this selector looks for

contextPath - the XPath to query

policyRoot - the root DOM Element for the policy containing this selector, which defines namespace mappings

mustBePresent - must resolution find a match

xpathVersion - the XPath version to use, which must be a valid XPath version string (the identifier for XPath 1.0 is provided in AbstractPolicy)

Method Detail

getInstance

public static AttributeSelector getInstance(Node root,
                                            String xpathVersion)
                                     throws ParsingException

Creates a new AttributeSelector based on the DOM root of the XML type. Note that as of XACML 1.1 the XPathVersion element is required in any policy that uses a selector, so if the xpathVersion string is null, then this will throw an exception.

Parameters:

root - the root of the DOM tree for the XML AttributeSelectorType XML type

xpathVersion - the XPath version to use, or null if this is unspecified (ie, not supplied in the defaults section of the policy)

Returns:

an AttributeSelector

Throws:

ParsingException - if the AttributeSelectorType was invalid

getType

public URI getType()

Returns the data type of the attribute values that this selector will resolve

Specified by:

getType in interface Evaluatable

Returns:

the data type of the values found by this selector

getContextPath

public String getContextPath()

Returns the XPath query used to resolve attribute values.

Returns:

the XPath query

mustBePresent

public boolean mustBePresent()

Returns whether or not a value is required to be resolved by this selector.

Returns:

true if a value is required, false otherwise

evaluatesToBag

public boolean evaluatesToBag()

Always returns true, since a selector always returns a bag of attribute values.

Specified by:

evaluatesToBag in interface Evaluatable

Returns:

true

getChildren

public List getChildren()

Always returns an empty list since selectors never have children.

Specified by:

getChildren in interface Evaluatable

Returns:

an empty List

getXPathVersion

public String getXPathVersion()

Returns the XPath version this selector is supposed to use. This is typically provided by the defaults section of the policy containing this selector.

Returns:

the XPath version

evaluate

public EvaluationResult evaluate(EvaluationCtx context)

Invokes the AttributeFinder used by the given EvaluationCtx to try to resolve an attribute value. If the selector is defined with MustBePresent as true, then failure to find a matching value will result in Indeterminate, otherwise it will result in an empty bag. To support the basic selector functionality defined in the XACML specification, use a finder that has only the SelectorModule as a module that supports selector finding.

Specified by:

evaluate in interface Evaluatable

Parameters:

context - representation of the request to search

Returns:

a result containing a bag either empty because no values were found or containing at least one value, or status associated with an Indeterminate result

encode

public void encode(OutputStream output)

Encodes this selector into its XML representation and writes this encoding to the given OutputStream with no indentation.

Specified by:

encode in interface Evaluatable

Parameters:

output - a stream into which the XML-encoded data is written

encode

public void encode(OutputStream output,
                   Indenter indenter)

Encodes this selector into its XML representation and writes this encoding to the given OutputStream with indentation.

Specified by:

encode in interface Evaluatable

Parameters:

output - a stream into which the XML-encoded data is written

indenter - an object that creates indentation strings