v0.2

1. It is no 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.
2. The library is no longer used as a Groovy Category. The Groovy Category are hidden. There are a few different ways to use:
3. The base Category API are slightly modified and are refactored to the JMSCoreCategory. Two sets of new APIs: GroovyJMS API and Groovy Messaging Service API are provided. The latter are designed base on the Groovy Sql.

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.
• GroovyJMS Core API
  • GroovyJMS Core API is based on the JMSCoreCategory, and shall be used in Execution Context. APIs are provided for JMS Resource and Destination
  • 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, getConnection() and getSession() methods are attached to any class, so you could "connection" and "session" like an pre-declared variable. The connection and session are attached to a threadlocal JMS instance
    • 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.
    • APIs
  • Message - MapMessage
    • mapMessage.toMap()
• GroovyJMS API
  • GroovyJMS API is based on the JMSCoreCategory, and shall be used in Execution Context
  • 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/Message as subject
    • For certain operations, you don't even need a subject
    • API in a spreadsheet [http://www.editgrid.com/publish/html/user/mingfai/24976908/A2:M24]
• Groovy Messaging Service API
  • Groovy Messaging Service API do not need to run in the Execution Context.
  • Groovy Messaging Service API is designed base on the Groovy core Sql API.

    Groovy SQL	Possible JMS Usage	Remarks/Comment
    Sql.newInstance()	JMS.newInstance(jmsConnectionFactory)	or just use new JMS()
    sql.eachRow	jms.eachMessage("myQueue"){m-> } jms.eachMessage("myQueue", [within:100]){}	jms.reply() could be used inside the closure reply is not implemented
    sql.firstRow	jms.firstMessage("myQueue") { println it.text }	jms.onMessage(topic:"mytopic"){ m -> } jms.onMessage(topic: "mytopic",durable:false){m -> }  jms.onMessage(queue:"myQueue"){ m -> } jms.onMessage(queue:"myQueue",topic: "mytopic"){ m -> }  //subscribe queue and topic at the same time //onMessage supports only one listener per session; if you need multiple subscription, use core API subscribe method and specific different subscriptionName jms.onMessage( topic: ['topic0', 'topic1']{ m -> } jms.onMessage( queue: ['queue0', 'qeueu1']{ m -> } jms.onMessage( topic:'mytopic', queue: ['queue0', 'qeueu1']{ m -> } jms.stopMessage( topic:"myTopic") // unsubscribe the listener jms.stopMessage( topic:['myTopic','myTopic2']) //TODO not implemented
    sql.execute()	def result = jms.receive( fromQueue:'myQueue', within:1000) jms.receive( fromQueue: 'myQueue', within:1000) { println it } jms.receive( fromQueue:['queue0','queue1'], within:1000, with: { println it})	fromTopic and fromQueue could be used together fromQueue always call receiveAll (to be enhanced to take a parameter to return only 1 message) if fromQueue has more than one queue, it return all messages of all queues fromTopic is asynchronous durable subscription, if both fromQueue and fromTopic are used together, any immediately available messages in any fromQueue will return first, and new message will be delivered to the same with closure in a later time either use jms.receive([:]){ }  or jms.receive([xxx:yyy, with:{}]) ; the former override the later within is a per queue timeout interval, not total; if there are more than one queue, each are retrieved in sequence
    sql.executeUpdate()	jms.send( toTopic:'myTopic', message:[key:value], replyTo:'')	toTopic and toQueue could be used together toTopic and toQueue support collection

  • All return value or closure handler result are JMS Message. It might be changed to String, Map, Byte[], Stream and Object in the future.
  • Similar to Sql, fine-grained control over connection/session could be done by passing in a JMS Connection or Session in the JMS.newInstance(), and user has to close the session/connection themselves