UniformDistributedTopicBean

Overview

A uniform distributed topic is a distributed topic whose members are configured as part of its configuration; since members share the same configuration, they are uniform. There is one member on each JMS Server that conforms to the targeting criteria of the uniform distributed topic. For example, if a uniform distributed topic is targeted to a cluster, then one member will be created on each JMS server in the cluster. Members are created and destroyed as the targeting is changed.

Related MBeans

This section describes attributes that provide access to other MBeans.

DeliveryFailureParams

DeliveryFailureParams control what should happen to messages when failures occur. They allow the adminstrator to control error destinations, logging and other actions that might be taken when a message can not be delivered or when other failures are detected.

DeliveryParamsOverrides

Many delivery parameters can be set by the JMS client. Setting an override causes the current value of a delivery parameter to be ignored and replaced by the value set here.

MessageLoggingParams

These parameters control how the WebLogic Server performs message logging.

They allow the adminstrator to configure the server to change message logging when a message life cycle changes are detected.

Multicast

Gets the multicast parameters for this destination.

Topics with certain quality of service allowments can receive a signifigant performance boost by using multicast to receive messages rather than using a connection oriented protocol like TCP. These parameters can be configured with the bean returned.

Quota

A Quota controls the allotment of system resources available to destinations. For example, the number of bytes a destination is allowed to store can be configured with a Quota.

Template

The JMS template from which the destination is derived. A template provides an efficient means of defining multiple destinations with similar configuration values.

If a JMS template is specified, destination parameters that are set to their default values will instead inherit their values from the JMS template at run-time. However, if a JMS template is not defined, then the configuration values for the destination must be specified as part of the destination.

Although you can dynamically modify the configuration of a JMS template, the configuration values on a destination are static.

Thresholds

A threshold is an action point that must be exceeded in order to produce a given effect. These action points may cause logging, flow control, or other actions, as defined by the specific points whose values have been exceeded.

TopicSubscriptionParams

Gets the subscription parameters for this topic.

TopicSubscriptionParamsBean specifies topic subscription parameters.

Attributes

This section describes the following attributes:

AttachSender

Specifies whether messages landing on this destination should attach the credential of the sending user. You should consult the JMSXUserID documentation in Programming WebLogic JMS before using this feature.

• Supports

  The JMSXUserID property is set with the security principal of the sending user if requested. The sender can request its identity to be attached to its messages by using a connection factory with the AttachJMSXUserID security property enabled.

• Never

  The JMSXUserID property is never set with the security principal of the sending user no matter how the AttachJMSXUserID property is configured on connection factories.

• Always

  The JMSXUserID property is always set with the security principal of the sending user no matter how the AttachJMSXUserID property is configured on connection factories.

This attribute is dynamically configurable. A dynamic change of this attribute will affect only messages received after the update has been made.

ConsumptionPausedAtStartup

Specifies whether consumption is paused on a destination at startup.

• default

  If a JMS template is specified, then this value inherits the template's Consumption Paused At Startup value. If no JMS template is configured for the destination, then the Default value is equivalent to false.

• false

  Consumption Paused is explicitly disabled for this destination.

• true

  Consumption Paused is explicitly turned on for this destination.

DefaultTargetingEnabled

Specifies whether this JMS resource defaults to the parent module's targeting or uses the subdeployment targeting mechanism.

When set to true, this resource implicitly inherits the targeting of its parent module. When set to false, this resource gets targeted based its subdeployment's targets, if one is specified.

DefaultUnitOfOrder

Specifies whether WebLogic Server creates a system-generated unit-of-order name based on the domain, JMS server, and destination name. Any message arriving at this destination that does not already belong to a unit-of-order is assigned this default name.

This field is recommended for advanced use. Generally, it is recommended to set a message unit-of-order using application calls or connection factory configuration. When relying on a destination default unit order to enforce ordering with a distributed destination, the application must be aware that unit-of-order routing doesn't apply. Instead the application must specifically ensure that any particular set of messages that must be processed in order are all sent to the same specific member destination even in the event of process failures or service migration.

DestinationKeys

The list of potential destination keys for sorting the messages that arrive on a JMS destination.

The keys are ordered from most significant to least significant. If more than one key is specified, a key based on the JMSMessageID can only be the last key in the list.

Note: If JMSMessageID is not defined in the key, it is implicitly assumed to be the last key and is set as "Ascending" (FIFO) for the sort order.

ForwardingPolicy

The uniform distributed topic message Forwarding Policy specifies whether a sent message is forwarded to all members.

The valid values are:

• Replicated

  - The default. All physical topic members receive each sent message. If a message arrives at one of the physical topic members, a copy of this message is forwarded to the other members of that uniform distributed topic. A subscription on any one particular member will get a copy of any message sent to the uniform distributed topic logical name or to any particular uniform distributed topic member.

• Partitioned

  - The physical member receiving the message is the only member of the uniform distributed topic that is aware of the message. When a message is published to the logical name of a Partitioned uniform distributed topic, it will only arrive on one particular physical topic member. Once a message arrives on a physical topic member, the message is not forwarded to the rest of the members of the uniform distributed destination, and subscribers on other physical topic members do not get a copy of that message. The Partitioned capability was added in WebLogic 10.3.4 (11gR1PS3).

A publisher that uses a logical JNDI name of a Replicated distributed topic is created on one member and every send call publishes messages to the same member regardless the value of the Load Balancing Enabled attribute. This is behavior is backward compatible with previous WebLogic Server releases when using a uniform distributed topic. Under the same conditions, a Partitioned distributed topic publishes to the same member only when the value of the Load Balancing Enabled attribute is set to false. If the value of the Load Balancing Enabled attribute is to true, a publisher to a Partitioned distributed topic publishes messages that are load balanced accross all the members of the uniform distributed topic.

Most new applications will use the new Partitioned forwarding policy in combination with a logical subscription topology on a uniform distributed topic that consists of: (1) a same named physical subscription created directly on each physical member, (2) a Client ID Policy of Unrestricted, and (3) a Subscription Sharing Policy of Sharable. WL 10.3.4 Message Driven Beans (MDBs) provides a Topic Messages Distribution Mode option to automatically setup this kind of topology.

Note: This attribute is ignored by standalone/singleton Topics, it only applies to distributed topics.

Id

Return the unique identifier of this bean instance.

IncompleteWorkExpirationTime

Specifies the maximum length of time, in milliseconds, before undelivered messages in an incomplete UOW are expired. Such messages will then follow the expiration policy defined for undeliverable messages.

Note: An error destination for UOW messages cannot be configured with a Unit-of-Work Handling Policy of Single Message Delivery value.

This attribute is effective only if the Unit-of-Work Handling Policy is set to Single Message Delivery value. A value of -1 means that UOW messages will never expire.

InsertionPausedAtStartup

Specifies whether new message insertion is paused on a destination at startup.

• default

  If a JMS template is specified, then this value inherits the template's Insertion Paused At Startup value. If no JMS template is configured for the destination, then the Default value is equivalent to false.

• false

  Insertion Paused is explicitly disabled for this destination.

• true

  Insertion Paused is explicitly turned on for this destination.

JMSCreateDestinationIdentifier

A reference name for a destination or a member of a distributed destination that provides a way to lookup that destination without JNDI using javax.jms.Session createQueue or createTopic. See "How to Lookup a Destination" in Programming JMS for more information on how to use this attribute.

This name must be unique within the scope of the JMS server to which this destination is targeted. However, it does not need to be unique within the scope of an entire JMS module or WebLogic Cluster. For example, two queues can have the same destination name as long as those queues are targeted to different JMS servers.

Note: Since this name must be unique within the scope of a JMS server, verify whether other JMS modules may contain destination names that conflict with this name. It is the responsibility of the deployer to resolve the destination names targeted to JMS servers.

JNDIName

The global JNDI name used to look up the destination within the JNDI namespace.

In a clustered environment, this name is propagated to the entire cluster. If you want the JNDI name to be bound only on the local server, and not propagated to the rest of the cluster, then use the Local JNDI Name parameter.

If not specified, the destination name will not be advertised through the global JNDI namespace.

LoadBalancingPolicy

Determines how messages are distributed to the members of this destination.

Choose from the following distribution techniques:

• Round-Robin

  The system maintains an ordering of physical topic members within the set by distributing the messaging load across the topic members one at a time in the order that they are defined in the configuration file. Each WebLogic Server instance maintains an identical ordering, but may be at a different point within the ordering. If weights are assigned to any of the topic members in the set, then those members appear multiple times in the ordering.

• Random

  The weight assigned to the topic members is used to compute a weighted distribution for the members of the set. The messaging load is distributed across the topic members by pseudo-randomly accessing the distribution. In the short run, the load will not be directly proportional to the weight. In the long run, the distribution will approach the limit of the distribution. A pure random distribution can be achieved by setting all the weights to the same value, which is typically set to 1.

Note: This attribute is ignored by standalone/singleton Queues and Topics, it only applies to distributed destinations.

LocalJNDIName

The local JNDI name used to look up the destination within the JNDI namespace of the server where the destination resource is targeted. In a clustered environment, this name is bound only on the local server instance and is not propagated to the rest of the cluster.

A destination can have both a local JNDI name and a (global) JNDI name.

MaximumMessageSize

The maximum size of a message that is accepted from producers on this destination.

The message size includes the message body, any user-defined properties, and the user-defined JMS header fields: JMSCorrelationID and JMSType. Producers sending messages that exceed the configured maximum message size for the destination receive a ResourceAllocationException.

The maximum message size is only enforced for the initial production of a message. Messages that are redirected to an error destination or forwarded to a member of a distributed destination are not checked for size. For instance, if a destination and its corresponding error destination are configured with a maximum message size of 128K bytes and 64K bytes, respectively, a message of 96K bytes could be redirected to the error destination (even though it exceeds the 64K byte maximum), but a producer could not directly send the 96K byte message to the error destination.

This attribute is dynamically configurable, but only incoming messages are impacted; stored messages are not impacted.

MessagingPerformancePreference

Controls how long destinations are willing to wait to create full batches of available messages (if at all) for delivery to consumers. At the minimum value, batching is disabled; at the default value, less-than-full batches will not wait and are delivered immediately with currently available messages; tuning higher than the default value controls the maximum wait time for additional messages before less-than-full batches are delivered to consumers.

The maximum message count of a full batch is controlled by the JMS connection factory's Messages Maximum setting.

Name

The name of this entity, represented in XML as an attribute.

Many of the elements within the JMS module are named entities. All of the named entities encased by a type in the XML file must be unique. This is the identifier used to delineate a particular entity within the JMS module.

This attribute cannot be modified externally from the module (for example, with a deployment plan) because it may be used inside the module referentially.

Notes

Optional information that you can include to describe this named JMS descriptor bean.

JMS module saves this note in the JMS descriptor file as XML PCDATA. All left angle brackets (<) are converted to the XML entity <. Carriage returns/line feeds are preserved.

Note:

If you create or edit a note from the Administration Console, the Administration Console does not preserve carriage returns/line feeds.

ProductionPausedAtStartup

Specifies whether new message production is paused on a destination at startup.

• default

  If a JMS template is specified, then this value inherits the template's Production Paused At Startup value. If no JMS template is configured for the destination, then the Default value is equivalent to false.

• false

  Production Paused is explicitly disabled for this destination.

• true

  Production Paused is explicitly turned on for this destination.

SAFExportPolicy

Specifies whether a user can send messages to a destination using Store-and-Forward.

• All

  All users can send messages to this destination using Store-and-Forward.

• None

  Remote users can not send messages to a destination using Store-and-Forward.

This attribute is dynamically configurable. A dynamic change of this attribute will affect only messages sent after the update has been made.

SubDeploymentName

Gets the name of the sub-deployment to use when targeting this entity

Entities are targeted using a sub-deployment with this name. The targets of the sub-deployment will be the targets of this entity.

UnitOfOrderRouting

Determines how a distributed destination member is selected as the destination for a message that is part of a unit-of-order. Hash, indicates that a message producer computes the member destination from the hashCode of the unit-of-order. PathService indicates that the configured Path Service determines the member destination.

Unit-of-Order Routing can be set programmatically with WLProducer, or administratively on the connection factory or destination.

Unit of Order Routing is not dynamically configurable.

Note: This attribute is ignored by standalone/singleton Queues and Topics, it only applies to distributed destinations.

UnitOfWorkHandlingPolicy

Specifies whether the Unit-of-Work (UOW) feature is enabled for this destination. A UOW is a set of messages that are processed as a single unit.

• Pass-Through

  By default, this destination does not treat messages as part of a UOW.

• Single Message Delivery

  This value should only be selected if UOW consumers are receiving messages on this destination. When selected, UOW messages are formed into a list and are consumed as an ObjectMessage containing the list.

Operations

This section describes the following operations:

addDestinationKey

Adds a destination key.

Adds a string to the list of keys to be used for sorting destinations. The string given will be added to the end of the list.

isSet

Return true if the given property has been explicitly set in this bean.

removeDestinationKey

Removes a destination key.

If the given string is in the list of keys used for sorting destinations, it will be removed from the list.

unSet

Restore the given property to its default value.