Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 25 Next »

This docs is for v0.2+

Overview

  1.  Start from v0.2, it is not longer a mandatory to provide a JMS ConnectionFactory. For a single JVM simple usage, you may use the default in-memory, non-persistent ActiveMQ connection factory, or you could configure your JMSProvider in several ways.

Usage

Concepts

  • GroovyJMS Execution Context
    • GroovyJMS mainly provide an execution context that you can use enhanced JMS API and convenient methods, and access to implicit variables
    • GroovyJMS is based on JMS and preserve any JMS concepts and keywords.  You could mix the usage of GroovyJMS API and JMS API in the execution context.
  • JMS Resource - ConnectionFactory, Connection and Session. You could create any of them outside the execution context and pass to the constructor of GroovyJMS, or you could use the implicitly created instances.
    • Refer to the next section about JMS ConnectionFactory
    • Inside the execution context, you could get a copy of the thread-scope connection and session instance. But you cannot set a new connection or session.
    • JMS Resources are used interchangeably when creating lower level JMS Resource
    • GroovyJMS provides high level API that use a single connection and session per thread. Unless you want a fine-grained control over the re-use of Connection and Session, it is not necessary to care about these resources.
  • JMS Destination - Queue, Topic
    • There are two types of JMS destination. GroovyJMS provides high level API to operate on any Queue or Topic, unless you need to get a reference for JMS Destination, you don't need to care about JMS Destinations.
    • Short API are provided for creating JMS Destinations. Similar to JMS Resource, calling subject is interchangable.
    • The return value of topic() and queue() are JMS Topic and Queue respectively. However, in GroovyJMS Execution Context, you could use some operation APIs such as send(), receive() etc. directly on JMS Destination.
  • GroovyJMS API
    • For simple usage, it is the only thing you need to learn. GroovyJMS API uses keywords from JMS API.
      • "send" and "receive" for Queue messages
      • "publish" and "subscribe" for Topic messages
    • You could call the API in two style
      • Message as subject, and sendTo
      • Or use the destination as subject
      • For certain operations, you don't even need a subject

JMS Connection Factory

To use GroovyJMS, you need to decide which JMS implementation you'll use. There are several options:

  1. use the default in-memory, not-persistent ActiveMQ broker and connection factory, this is created by the ActiveMQJMSProvider class. Notice that the ActiveMQJMSProvider will start a ActiveMQ broker if it is not existed already, and will add a "vm://localhost" transport connector URL if not existed. In this case, the syntax is as simple as:
  2. Provide a JMSProvider by
    1. specific a "groovy.jms.provider" system property that point to a class that implements groovy.jms.provider.JMSProvider
    2. set a JMSProvider to the JMS.provider static variable, e.g.
  3. Provide Connection Factory or Connection in runtime. it is the most recommended approach. You may utilize your JEE container or dependency injection framework to inject the required JMS resources to your class, and support the connection or factory to GroovyJMS.

Unsupported Features or Limitation

  • nested usage is not supported yet. you may still use the lib in nested manner but you have manage the Connection and Session carefully.
    • For example:
    • you are recommended to avoid nestled usage. If you use it, try to use a multiple connection.
  • No labels