File: README — Documentation for jruby-jms (0.11.0)

jruby-jms

http://github.com/reidmorrison/jruby-jms

Current Activities & Backward Compatibility

The API is relatively stable at this point and I do not expect any breaking changes at this point.

There may still be some minor changes to the API to make things better and/or simpler. Once the code goes to V1.0.0 I will make every effort to not break the existing interface in any way.

Feedback is welcome and appreciated :)

Introduction

jruby-jms attempts to "rubify" the Java JMS API without compromising performance. It does this by sprinkling "Ruby-goodness" into the existing JMS Java interfaces, I.e. By adding Ruby methods to the existing classes and interfaces. Since jruby-jms exposes the JMS Java classes directly there is no performance impact that would have been introduced had the entire API been wrapped in a Ruby layer.

In this way, using regular Ruby constructs a Ruby program can easily interact with JMS in a highly performant way. Also, in this way you are not limited to whatever the Ruby wrapper would have exposed, since the entire JMS API is available to you at any time.

The initial internal use version of JRuby-JMS was created in 2008. It has been in use in production since 2009.

Install

jgem install jruby-jms

Simplification

One of the difficulties with the regular JMS API is that it use completely separate classes for Topics and Queues in JMS 1.1. This means that once a program writes to a Queue for example, that without changing the program it could not be changed to write to a topic. Also a consumer on a topic or a queue are identical. jruby-jms fixes this issue by allowing you to have a Consumer or Producer that is independent of whether it is producing or consuming to/from or a Topic or a Queue. The complexity of which JMS class is used is taken care of by jruby-jms.

Concepts & Terminology

Java Message Service (JMS) API

The JMS API is a standard interface part of Java EE 6 as a way for programs to send and receive messages through a messaging and queuing system.

For more information on the JMS API: http://download.oracle.com/javaee/6/api/index.html?javax/jms/package-summary.html

Broker / Queue Manager

Depending on which JMS provider you are using they refer to their centralized server as either a Broker or Queue Manager. The Broker or Queue Manager is the centralized "server" through which all messages pass through.

Some Brokers support an in-vm broker instance so that messages can be passed between producers and consumers within the same Java Virtual Machine (JVM) instance. This removes the need to make any network calls. Highly recommended for passing messages between threads in the same JVM.

Connection

In order to connect to any broker the Client JMS application must create a connection. In traditional JMS a ConnectionFactory is used to create connections. In jruby-jms the JMS::Connection takes care of the complexities of dealing with the factory class, just pass the required parameters to Connection.new at it takes care of the rest.

Queue

A queue used for holding messages. The queue is defined prior to the message being sent and is used to hold the messages. The consumer does not have to be running in order to receive messages.

Topic

Instead of sending messages to a single queue, a topic can be used to publish messages and allow multiple consumers to register for messages that match the topic they are interested in

Producer

Producers write messages to queues or topics

ActiveMQ Example:

require 'rubygems'
require 'jms'

# Connect to ActiveMQ
config = {
  :factory => 'org.apache.activemq.ActiveMQConnectionFactory',
  :broker_url => 'tcp://localhost:61616',
  :require_jars => [
    "~/Applications/apache-activemq-5.5.0/activemq-all-5.5.0.jar",
    "~/Applications/apache-activemq-5.5.0/lib/optional/slf4j-log4j12-1.5.11.jar",
    "~/Applications/apache-activemq-5.5.0/lib/optional/log4j-1.2.14.jar"
  ]
}

JMS::Connection.session(config) do |session|
  session.producer(:queue_name => 'ExampleQueue') do |producer|
    producer.send(session.message("Hello World"))
  end
end

Consumer

Consumers read message from a queue or topic

ActiveMQ Example:

require 'rubygems'
require 'jms'

# Connect to ActiveMQ
config = {
  :factory => 'org.apache.activemq.ActiveMQConnectionFactory',
  :broker_url => 'tcp://localhost:61616',
  :require_jars => ["~/Applications/apache-activemq-5.4.2/activemq-all-5.4.2.jar"]
}

JMS::Connection.session(config) do |session|
  session.consume(:queue_name => 'ExampleQueue', :timeout=>1000) do |message|
    p message
  end
end

Overview

jruby-jms is a complete JRuby API into the Java Messaging Specification (JMS) V1.1 followed by several JMS Providers.

Threading

A JMS::Connection instance can be shared between threads, whereas a session, consumer, producer, and any artifacts created by the session should only be used by one thread at a time.

For consumers, it is recommended to create a session for each thread and leave that thread blocked on Consumer.receive. Or, even better use Connection.on_message which will create a session, within which any message received from the specified queue or topic match will be passed to the block.

Logging

jruby-jms detects the logging available in the current environment. When running under Rails it will use the Rails logger, otherwise the standard Ruby logger. The logger can also be replaced by calling Connection.logger=

Dependencies

JMS V1.1 Provider

In order to communicate with a JMS V 1.1 provider jruby-jms needs the jar files supplied by the JMS provider. As in the examples above the jar files can be specified in the configuration element :require_jars. Otherwise, the jars must be explicitly required in the Ruby code: require "~/Applications/apache-activemq-5.4.2/activemq-all-5.4.2.jar"

JRuby

jruby-jms has been tested against JRuby 1.5.1 and 1.6.1, but should work with any current JRuby version.

Development

Want to contribute to jruby-jms?

First clone the repo and run the tests:

git clone git://github.com/reidmorrison/jruby-jms.git
cd jruby-jms
jruby -S rake test

Feel free to submit any issues and we'll try to resolve it.

Contributing

Once you've made your great commits:

Fork jruby-jms
Create a topic branch - git checkout -b my_branch
Push to your branch - git push origin my_branch
Create an Issue with a link to your branch
That's it!

Author

Reid Morrison :: [email protected] :: @reidmorrison

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.