/**
* Used to get the current time, date, or dateTime. If one of those values isn't being asked for,
* or if the types are wrong, then an empty bag is returned.
*
* @param attributeType the datatype of the attributes to find, which must be time, date, or
* dateTime for this module to resolve a value
* @param attributeId the identifier of the attributes to find, which must be one of the three
* ENVIRONMENT_* fields for this module to resolve a value
* @param issuer the issuer of the attributes, or null if unspecified
* @param subjectCategory the category of the attribute or null, which ignored since this only
* handles non-subjects
* @param context the representation of the request data
* @param designatorType the type of designator, which must be ENVIRONMENT_TARGET for this module
* to resolve a value
* @return the result of attribute retrieval, which will be a bag with a single attribute, an
* empty bag, or an error
*/
public EvaluationResult findAttribute(
URI attributeType,
URI attributeId,
URI issuer,
URI subjectCategory,
EvaluationCtx context,
int designatorType) {
// we only know about environment attributes
if (designatorType != AttributeDesignator.ENVIRONMENT_TARGET)
return new EvaluationResult(BagAttribute.createEmptyBag(attributeType));
// figure out which attribute we're looking for
String attrName = attributeId.toString();
if (attrName.equals(ENVIRONMENT_CURRENT_TIME)) {
return handleTime(attributeType, issuer, context);
} else if (attrName.equals(ENVIRONMENT_CURRENT_DATE)) {
return handleDate(attributeType, issuer, context);
} else if (attrName.equals(ENVIRONMENT_CURRENT_DATETIME)) {
return handleDateTime(attributeType, issuer, context);
}
// if we got here, then it's an attribute that we don't know
return new EvaluationResult(BagAttribute.createEmptyBag(attributeType));
}
/** Handles requests for the current DateTime. */
private EvaluationResult handleDateTime(URI type, URI issuer, EvaluationCtx context) {
// make sure they're asking for a dateTime attribute
if (!type.toString().equals(DateTimeAttribute.identifier))
return new EvaluationResult(BagAttribute.createEmptyBag(type));
// get the value from the context
return makeBag(context.getCurrentDateTime());
}
/**
* Creates an empty evaluation result for the provided attribute type.
*
* @param attributeType The URI specifying the attribute type.
* @return Returns an empty evaluation result.
*/
public static EvaluationResult createEmptyEvaluationResult(final URI attributeType) {
return new EvaluationResult(BagAttribute.createEmptyBag(attributeType));
}