org.globus.wsrf.impl
Class TopicExpressionEngineImpl

java.lang.Object
  org.globus.wsrf.impl.TopicExpressionEngineImpl

All Implemented Interfaces:

TopicExpressionEngine

public class TopicExpressionEngineImpl

extends java.lang.Object

implements TopicExpressionEngine

Resolves topic expressions over topic lists. The engine looks for topic expression evaluators under "java:comp/env/topic/eval" context.

See Also:

TopicList

Field Summary

private java.util.Map	evaluators
private static org.globus.util.I18n	i18n
(package private) static org.apache.commons.logging.Log	logger
private static java.lang.String	TOPIC_EXPRESSION_EVALUATOR_CONTEXT

Constructor Summary

TopicExpressionEngineImpl()

Method Summary

java.util.List	getConcretePath(TopicExpressionType topicExpression) Converts the expression from dialect specific form to a ordered list of QNames.
TopicExpressionEvaluator	getEvaluator(java.lang.String dialect) Gets the evaluator currently registered to handle a topic expression of the specified dialect.
static TopicExpressionEngine	getInstance() Get the default topic expression engine instance (currently used to hide JNDI lookup details, may change in the future)
java.lang.String[]	getSupportedDialects() Returns a list of URIs representing the registered topic expression dialects
void	refresh() Refresh the set of registered topic expression evaluators using information discovered from the JNDI registry.
void	registerEvaluator(TopicExpressionEvaluator evaluator) registers a new evaluator that can be used to evaluate topic expressions
java.util.Collection	resolveTopicExpression(TopicExpressionType topicExpression, TopicList topicList) Resolves a topic expression using the passed topic list.

Methods inherited from class java.lang.Object

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

Field Detail

TOPIC_EXPRESSION_EVALUATOR_CONTEXT

private static java.lang.String TOPIC_EXPRESSION_EVALUATOR_CONTEXT

i18n

private static org.globus.util.I18n i18n

logger

static org.apache.commons.logging.Log logger

evaluators

private java.util.Map evaluators

Constructor Detail

TopicExpressionEngineImpl

public TopicExpressionEngineImpl()

Method Detail

getInstance

public static TopicExpressionEngine getInstance()

Get the default topic expression engine instance (currently used to hide JNDI lookup details, may change in the future)

Returns:

The default topic expression engine instance

refresh

public void refresh()

Refresh the set of registered topic expression evaluators using information discovered from the JNDI registry. This method removes any previously registered topic expression evaluators, so handle with care.

registerEvaluator

public void registerEvaluator(TopicExpressionEvaluator evaluator)

Description copied from interface: TopicExpressionEngine

registers a new evaluator that can be used to evaluate topic expressions

Specified by:

registerEvaluator in interface TopicExpressionEngine

Parameters:

evaluator - implementation of evaluator to be used for evaluating topic expressions

getEvaluator

public TopicExpressionEvaluator getEvaluator(java.lang.String dialect)

Description copied from interface: TopicExpressionEngine

Gets the evaluator currently registered to handle a topic expression of the specified dialect.

Specified by:

getEvaluator in interface TopicExpressionEngine

Returns:

the matching topic expression evaluator or null if none was found

resolveTopicExpression

public java.util.Collection resolveTopicExpression(TopicExpressionType topicExpression,
                                                   TopicList topicList)
                                            throws UnsupportedTopicExpressionDialectException,
                                                   TopicExpressionResolutionException,
                                                   InvalidTopicExpressionException,
                                                   TopicExpressionException

Description copied from interface: TopicExpressionEngine

Resolves a topic expression using the passed topic list. The appropraite TopicExpressionEvaluator is used based on the dialect element.

Specified by:

resolveTopicExpression in interface TopicExpressionEngine

Parameters:

topicExpression - topic expression

topicList - the topic list to apply the expression to

Returns:

the set of topics the expression evaluated to

Throws:

TopicExpressionResolutionException - if the expression could not be evaluated

UnsupportedTopicExpressionDialectException - if the topic expression dialect is not supported

InvalidTopicExpressionException - if the topic expression is invalid

TopicExpressionException - if any other error occurs

getConcretePath

public java.util.List getConcretePath(TopicExpressionType topicExpression)
                               throws UnsupportedTopicExpressionDialectException,
                                      TopicExpressionResolutionException,
                                      InvalidTopicExpressionException,
                                      TopicExpressionException

Description copied from interface: TopicExpressionEngine

Converts the expression from dialect specific form to a ordered list of QNames. This method throws an exception if the expression does not evaluate to a concrete topic path.

Specified by:

getConcretePath in interface TopicExpressionEngine

Parameters:

topicExpression - topic expression

Returns:

a list of QNames describing the concrete topic path

Throws:

TopicExpressionException - if any other error occurs

UnsupportedTopicExpressionDialectException - if the topic expression dialect is not supported

InvalidTopicExpressionException - if the topic expression is invalid

TopicExpressionResolutionException - if the expression could not be evaluated

getSupportedDialects

public java.lang.String[] getSupportedDialects()

Description copied from interface: TopicExpressionEngine

Returns a list of URIs representing the registered topic expression dialects

Specified by:

getSupportedDialects in interface TopicExpressionEngine

Returns:

the list of supported dialects