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JMS Client Assets

The Java Message Service (JMS) is a specification that allows Java programs to interact with enterprise messaging systems. The original version is 1.0. The latest version is 1.1.

JMS includes the following terminology:

• JMS client: A Java program that uses JMS to communicate with a messaging system.
• JMS provider: A messaging system that implements JMS.

You can create assets for the following types of objects that the JMS clients use:

• Connection factory
• Connection
• Session
• Producer
• Consumer
• Destination

In the editor for each JMS client asset, each parameter has a tooltip that describes the purpose of the parameter.

The following graphic shows how a JMS client handles request messages and response messages.

Connection Factories

A connection factory is used to create connections.

The connection factories can be characterized in terms of how they are initialized:

• Generic connection factory: Initialized by using the Java Naming and Directory Interface (JNDI).
• Direct connection factory: Initialized in a way that is specific to a JMS provider. This type of connection factory has its own, often large, set of parameters.

The connection factories can also be characterized in terms of the destinations that they support:

• Queue connection factory: Supports queues only. This type is from JMS version 1.0.
• Topic connection factory: Supports topics only. This type is from JMS version 1.0.
• Connection factory: If a connection factory is not specified as either of the preceding types, then it supports both queues and topics.

Many connection factory assets are a combination of these two categories. For example, the Direct JMS 1.0 Topic Connection Factory for TIBCO EMS asset is a direct connection factory that supports topics only.

Connections

A connection represents an active connection with a JMS provider. Connections are used to create sessions.

Connections can be characterized in terms of the destinations that they support:

• Queue connection: Supports queues only. This type is from JMS version 1.0.
• Topic connection: Supports topics only. This type is from JMS version 1.0.
• Connection: If a connection is not specified as either of the preceding types, then it supports both queues and topics.

A connection must remain open while its sessions are open.

Sessions

A session is used to create producers and consumers.

Sessions can be characterized in terms of the destinations that they support:

• Queue session: Supports queues only. This type is from JMS version 1.0.
• Topic session: Supports topics only. This type is from JMS version 1.0.
• Session: If a session is not specified as either of the preceding types, then it supports both queues and topics.

A session must remain open while its producers and consumers are active.

Producers

A producer is used to send a message to a destination.

DevTest has only one type of producer.

Consumers

A consumer is used to receive a message from a destination.

DevTest has only one type of consumer. However, you can use a consumer in either of two ways:

• Synchronously: While a client is waiting to receive a message, the client cannot do anything else.
• Asynchronously: While a client is waiting to receive a message, the client can perform other tasks.

Destinations

A destination represents a location on the JMS platform where messages are placed.

Destinations are divided into queues and topics:

• Queue: A destination that supports the point-to-point messaging model. When a message is sent to a queue, only one receiver can receive the message.
• Topic: A destination that supports the publish/subscribe messaging model. When a message is sent to a topic, multiple receivers can receive the message.

Destinations can also be characterized in terms of how they are created:

• JNDI destination: Initialized by using the Java Naming and Directory Interface (JNDI).
• Temp JNDI destination: A JMS session can be used to create a destination temporarily. This destination exists as long as the session is open, and is deleted when the session is closed.
• Destination: A static destination is not specified as either of the preceding types, and is obtained through the JMS session.

Destination assets are a combination of these two categories. For example, the JMS JNDI Queue asset is a point-to-point destination that is initialized through JNDI.