weblogic.jms.common

Class JMSSQLFilter

java.lang.Object

weblogic.messaging.common.SQLFilter

weblogic.jms.common.JMSSQLFilter

All Implemented Interfaces:

weblogic.messaging.kernel.Filter

public class JMSSQLFilter
extends weblogic.messaging.common.SQLFilter

This is an implementation of the messaging kernel's Filter interface for use by JMS. It supports the JMS SQL query syntax.

In this Filter implementation, the "expression" is a string that must match JMS SQL filter syntax, plus the special JMS "noLocal" flag. The expression must be created by creating an instance of the class JMSSQLExpression. The object to match must be a weblogic.jms.common.MessageImpl.

There are two data structures in this implementation. The first is used for the special case of a "xxx IS NOT NULL" selector. In this case, we use a map where the key is the value of "xxx" and the values are a list of queues. This gives us constant-time matching of messages, depending on the number of properties in the JMS message; constant-time insertion of new subscribers; and linear-time removal, depending on the number of "xxx IS NOT NULL" consumers.

The second data structure is used by all other types of selectors. It consists of a an ordered map (we use the LinkedHashMap class) of all the consumers. To implement "fairness", the first matching consumer is "rotated" to the end of the list by removing it and re-inserting it.

In this data structure, Each consumer points to an expression, and multiple consumers may point to the same expression, to save evaluation of duplicate selectors. This gives us linear-time matching of messages, depending mostly on the number of unique selectors; constant-time insertion of new subscribers; and constant-time removal.

Excluded in public API Reference.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	JMSSQLFilter.Exp This is the class for evaluating a regular JMS SQL expression.

Field Summary

Fields

Modifier and Type	Field and Description
private static boolean	enable1213NoLocalSemanticForDuraSubRestrictedClientID
private java.util.Map<weblogic.messaging.kernel.Sink,weblogic.messaging.kernel.Expression>	filteredForwardedAndMoreSubs Subscribers with only filtered forwarded selector ("NOT JMS_WL_DDForwarded AND (other expression)")
private java.util.Map	filteredForwardedIndexedSubs This map associates the "NOT JMS_WL_DDForwarded AND (value IS NOT NULL)" subscriber ID with an object.
private java.util.Set<weblogic.messaging.kernel.Sink>	filteredForwardedSubs Subscribers with only filtered forwarded selector ("NOT JMS_WL_DDForwarded")
private java.util.Map	indexedSubscribers This map associates the "value IS NOT NULL" subscriber ID with an object.

Fields inherited from class weblogic.messaging.common.SQLFilter

kernel, lock, subscribers, variableBinder

Constructor Summary

Constructors

Constructor and Description
JMSSQLFilter(weblogic.messaging.kernel.Kernel kernel)

Method Summary

Modifier and Type	Method and Description
private void	addIndexedSubscriber(weblogic.messaging.kernel.Sink sink, java.lang.String selectorId, boolean isFilteredForwarded)
weblogic.messaging.kernel.Expression	createExpression(java.lang.Object exp) Parse the expression and create an object for later evaluation.
java.util.Collection	match(weblogic.messaging.kernel.MessageElement message) Override the generic "match" method to provide indexed subscriber support.
private void	removeIndexedSubscriber(weblogic.messaging.kernel.Sink sink)
void	subscribe(weblogic.messaging.kernel.Sink sink, weblogic.messaging.kernel.Expression exp) Here, we override the normal subscription mechanism from SQLFilter to deal with indexed subscribers.
void	unsubscribe(weblogic.messaging.kernel.Sink sink)

Methods inherited from class weblogic.messaging.common.SQLFilter

match, resubscribe

Methods inherited from class java.lang.Object

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

Field Detail

enable1213NoLocalSemanticForDuraSubRestrictedClientID

private static boolean enable1213NoLocalSemanticForDuraSubRestrictedClientID

indexedSubscribers

private final java.util.Map indexedSubscribers

This map associates the "value IS NOT NULL" subscriber ID with an object. The object will be either a Set or a single object depending on how many there are.

filteredForwardedIndexedSubs

private final java.util.Map filteredForwardedIndexedSubs

This map associates the "NOT JMS_WL_DDForwarded AND (value IS NOT NULL)" subscriber ID with an object. The object will be either a Set or a single object depending on how many there are.

filteredForwardedSubs

private final java.util.Set<weblogic.messaging.kernel.Sink> filteredForwardedSubs

Subscribers with only filtered forwarded selector ("NOT JMS_WL_DDForwarded")

filteredForwardedAndMoreSubs

private final java.util.Map<weblogic.messaging.kernel.Sink,weblogic.messaging.kernel.Expression> filteredForwardedAndMoreSubs

Subscribers with only filtered forwarded selector ("NOT JMS_WL_DDForwarded AND (other expression)")

Constructor Detail

JMSSQLFilter

public JMSSQLFilter(weblogic.messaging.kernel.Kernel kernel)

Method Detail

createExpression

public weblogic.messaging.kernel.Expression createExpression(java.lang.Object exp)
                                                      throws weblogic.messaging.kernel.KernelException

Parse the expression and create an object for later evaluation. This method may return null if the expression is a null or empty string. The object passed must be an instance of the JMSSQLExpression class.

Specified by:

createExpression in interface weblogic.messaging.kernel.Filter

Overrides:

createExpression in class weblogic.messaging.common.SQLFilter

Throws:

weblogic.messaging.kernel.KernelException

subscribe

public void subscribe(weblogic.messaging.kernel.Sink sink,
                      weblogic.messaging.kernel.Expression exp)

Here, we override the normal subscription mechanism from SQLFilter to deal with indexed subscribers.

Specified by:

subscribe in interface weblogic.messaging.kernel.Filter

Overrides:

subscribe in class weblogic.messaging.common.SQLFilter

addIndexedSubscriber

private void addIndexedSubscriber(weblogic.messaging.kernel.Sink sink,
                                  java.lang.String selectorId,
                                  boolean isFilteredForwarded)

unsubscribe

public void unsubscribe(weblogic.messaging.kernel.Sink sink)

Specified by:

unsubscribe in interface weblogic.messaging.kernel.Filter

Overrides:

unsubscribe in class weblogic.messaging.common.SQLFilter

removeIndexedSubscriber

private void removeIndexedSubscriber(weblogic.messaging.kernel.Sink sink)

match

public java.util.Collection match(weblogic.messaging.kernel.MessageElement message)

Override the generic "match" method to provide indexed subscriber support.

Specified by:

match in interface weblogic.messaging.kernel.Filter

Overrides:

match in class weblogic.messaging.common.SQLFilter