Module: JMS::Session

Defined in:
lib/jms/session.rb

Overview

For each thread that will be processing messages concurrently a separate session is required. All sessions can share a single connection to the same JMS Provider.

Interface javax.jms.Session

See: download.oracle.com/javaee/6/api/javax/jms/Session.html

Other methods still directly accessible through this class:

create_browser(queue, message_selector)

Creates a QueueBrowser object to peek at the messages on the specified queue using a message selector.

create_bytes_message()

Creates a BytesMessage object

create_consumer(destination)

Creates a MessageConsumer for the specified destination
See: Connection::consumer

Example:
   destination = session.create_destination(:queue_name => "MyQueue")
   session.create_consumer(destination)

create_consumer(destination, message_selector)

Creates a MessageConsumer for the specified destination, using a message selector

create_consumer(destination, message_selector, boolean NoLocal)

Creates MessageConsumer for the specified destination, using a message selector

create_durable_subscriber(Topic topic, java.lang.String name)

Creates a durable subscriber to the specified topic

create_durable_subscriber(Topic topic, java.lang.String name, java.lang.String messageSelector, boolean noLocal)

Creates a durable subscriber to the specified topic, using a message selector and specifying whether messages published by its own connection should be delivered to it.

create_map_Message()

Creates a MapMessage object

create_message()

Creates a Message object

create_object_message()

Creates an ObjectMessage object

create_object_message(java.io.Serializable object)

Creates an initialized ObjectMessage object

create_producer(destination)

Creates a MessageProducer to send messages to the specified destination

create_queue(queue_name)

Creates a queue identity given a Queue name

create_stream_message()

Creates a StreamMessage object

create_temporary_queue()

Creates a TemporaryQueue object

create_temporary_topic()

Creates a TemporaryTopic object

create_text_message()

Creates a TextMessage object

create_text_message(text)

Creates an initialized TextMessage object

create_topic(topic_name)

Creates a topic identity given a Topic name

acknowledge_mode()

Returns the acknowledgement mode of the session

message_listener()

Returns the session's distinguished message listener (optional).

transacted?

Indicates whether the session is in transacted mode

recover()

Stops message delivery in this session, and restarts message delivery with the oldest unacknowledged message

rollback()

Rolls back any messages done in this transaction and releases any locks currently held

message_listener=(MessageListener listener)

Sets the session's distinguished message listener (optional)

unsubscribe(name)

Unsubscribes a durable subscription that has been created by a client

Interface javax.jms.Session

Instance Method Summary collapse

Instance Method Details

#browse(params = {}, &proc) ⇒ Object

Browse the specified queue, calling the Proc supplied for each message found

Parameters:

:queue_name     => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

:selector   => Filter which messages should be returned from the queue
               Default: All messages



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# File 'lib/jms/session.rb', line 470

def browse(params={}, &proc)
  self.browser(params) {|b| b.each(params, &proc)}
end

#browser(params, &proc) ⇒ Object

Return a browser for the destination A browser can read messages non-destructively from the queue It cannot browse Topics!

Call the Proc if supplied, then automatically close the consumer

Parameters:

:queue_name     => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

:selector   => Filter which messages should be returned from the queue
               Default: All messages



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# File 'lib/jms/session.rb', line 437

def browser(params, &proc)
  raise "Session::browser requires a code block to be executed" unless proc

  destination = create_destination(params)
  b = nil
  if params[:selector]
    b = create_browser(destination, params[:selector])
  else
    b = create_browser(destination)
  end

  if proc
    begin
      proc.call(b)
    ensure
      b.close
      b = nil
    end
  end
  b
end

#consume(params, &proc) ⇒ Object

Consume all messages for the destination A consumer can read messages from the queue or topic

Parameters:

:queue_name     => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:topic_name => String: Name of the Topic to write to or subscribe to
               Symbol: :temporary => Create temporary topic
               Mandatory unless :queue_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

:selector   => Filter which messages should be returned from the queue
               Default: All messages
:no_local   => Determine whether messages published by its own connection
               should be delivered to it
               Default: false

:timeout Follows the rules for MQSeries:
  -1 : Wait forever
   0 : Return immediately if no message is available
   x : Wait for x milli-seconds for a message to be received from the broker
        Note: Messages may still be on the queue, but the broker has not supplied any messages
                  in the time interval specified
   Default: 0



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# File 'lib/jms/session.rb', line 413

def consume(params, &proc)
  c = self.consumer(params)
  begin
    c.each(params, &proc)
  ensure
    c.close
  end
end

#consumer(params, &proc) ⇒ Object

Return a consumer for the destination A consumer can read messages from the queue or topic

Call the Proc if supplied, then automatically close the consumer

Parameters:

:queue_name => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:topic_name => String: Name of the Topic to write to or subscribe to
               Symbol: :temporary => Create temporary topic
               Mandatory unless :queue_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

:selector   => Filter which messages should be returned from the queue
               Default: All messages
:no_local   => Determine whether messages published by its own connection
               should be delivered to it
               Default: false



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# File 'lib/jms/session.rb', line 363

def consumer(params, &proc)
  destination = create_destination(params)
  c = nil
  if params[:no_local]
    c = create_consumer(destination, params[:selector] || '', params[:no_local])
  elsif params[:selector]
    c = create_consumer(destination, params[:selector])
  else
    c = create_consumer(destination)
  end

  if proc
    begin
      proc.call(c)
    ensure
      c.close
      c = nil
    end
  end
  c
end

#create_destination(params) ⇒ Object

Create the destination based on the parameter supplied

The idea behind this method is to allow the decision as to whether one is sending to a topic or destination to be transparent to the code. The supplied parameters can be externalized into say a YAML file so that today it writes to a queue, later it can be changed to write to a topic so that multiple parties can receive the same messages.

Note: For Temporary Queues and Topics, remember to delete them when done

or just use ::destination instead with a block and it will take care
of deleting them for you

To create a queue:

session.create_destination(:queue_name => 'name of queue')

To create a temporary queue:

session.create_destination(:queue_name => :temporary)

To create a queue:

session.create_destination('queue://queue_name')

To create a topic:

session.create_destination(:topic_name => 'name of queue')

To create a temporary topic:

session.create_destination(:topic_name => :temporary)

To create a topic:

session.create_destination('topic://topic_name')

Create the destination based on the parameter supplied

Parameters:

:queue_name => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:topic_name => String: Name of the Topic to write to or subscribe to
               Symbol: :temporary => Create temporary topic
               Mandatory unless :queue_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

Returns the result of the supplied block



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# File 'lib/jms/session.rb', line 194

def create_destination(params)
  # Allow a Java JMS destination object to be passed in
  return params[:destination] if params[:destination] && params[:destination].java_kind_of?(JMS::Destination)

  queue_name = nil
  topic_name = nil

  if params.is_a? String
    queue_name = params['queue://'.length..-1] if params.start_with?('queue://')
    topic_name = params['topic://'.length..-1] if params.start_with?('topic://')
  else
    # :q_name is deprecated
    queue_name = params[:queue_name] || params[:q_name]
    topic_name = params[:topic_name]
  end

  raise "Missing mandatory parameter :queue_name or :topic_name to Session::producer, Session::consumer, or Session::browser" unless queue_name || topic_name

  if queue_name
    queue_name == :temporary ? create_temporary_queue : create_queue(queue_name)
  else
    topic_name == :temporary ? create_temporary_topic : create_topic(topic_name)
  end
end

#destination(params = {}, &block) ⇒ Object

Create a queue or topic to send or receive messages from

A block must be supplied so that if it is a temporary topic or queue it will be deleted after the proc is complete

To create a queue:

session.destination(:queue_name => 'name of queue')

To create a temporary queue:

session.destination(:queue_name => :temporary)

To create a topic:

session.destination(:topic_name => 'name of queue')

To create a temporary topic:

session.destination(:topic_name => :temporary)

Create the destination based on the parameter supplied

Parameters:

:queue_name => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:topic_name => String: Name of the Topic to write to or subscribe to
               Symbol: :temporary => Create temporary topic
               Mandatory unless :queue_name is supplied
  Or,
:destination=> Explicit javaxJms::Destination to use

Returns the result of the supplied block



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# File 'lib/jms/session.rb', line 250

def destination(params={}, &block)
  raise "Missing mandatory Block when calling JMS::Session#destination" unless block
  dest = nil
  begin
    dest = create_destination(params)
    block.call(dest)
  ensure
    # Delete Temporary Queue / Topic
    dest.delete if dest && dest.respond_to?(:delete)
  end
end

#message(data, type = nil) ⇒ Object

Create a new message instance based on the type of the data being supplied

String (:to_str)    => TextMessage
Hash   (:each_pair) => MapMessage

Duck typing is used to determine the type. If the class responds to :to_str then it is considered a String. Similarly if it responds to :each_pair it is considered to be a Hash

If automated duck typing is not desired, the type of the message can be specified by setting the parameter ‘type’ to any one of:

:text   => Creates a Text Message
:map    => Creates a Map Message
:bytes  => Creates a Bytes Message



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# File 'lib/jms/session.rb', line 124

def message(data, type=nil)
  jms_message = nil
  type ||= if data.respond_to?(:to_str, false)
    :text
  elsif data.respond_to?(:each_pair, false)
    :map
  else
    raise "Unknown data type #{data.class.to_s} in Message"
  end

  case type
  when :text
    jms_message = self.createTextMessage
    jms_message.text = data.to_str
  when :map
    jms_message = self.createMapMessage
    jms_message.data = data
  when :bytes
    jms_message = self.createBytesMessage
    jms_message.write_bytes(data.to_java_bytes)
  else
    raise "Invalid type #{type} requested"
  end
  jms_message
end

#producer(params, &proc) ⇒ Object

Return a producer for the queue name supplied A producer supports sending messages to a Queue or a Topic

Call the Proc if supplied, then automatically close the producer

Parameters:

:queue_name     => String: Name of the Queue to return
               Symbol: :temporary => Create temporary queue
               Mandatory unless :topic_name is supplied
  Or,
:topic_name => String: Name of the Topic to write to or subscribe to
               Symbol: :temporary => Create temporary topic
               Mandatory unless :queue_name is supplied
  Or,
:destination=> Explicit JMS::Destination to use



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# File 'lib/jms/session.rb', line 329

def producer(params, &proc)
  p = self.create_producer(self.create_destination(params))
  if proc
    begin
      proc.call(p)
    ensure
      p.close
      p = nil
    end
  end
  p
end

#queue(queue_name, &block) ⇒ Object

Return the queue matching the queue name supplied Call the Proc if supplied



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# File 'lib/jms/session.rb', line 264

def queue(queue_name, &block)
  q = create_queue(queue_name)
  block.call(q) if block
  q
end

#temporary_queue(&block) ⇒ Object

Return a temporary queue The temporary queue is deleted once the block completes If no block is supplied then it should be deleted by the caller when no longer needed



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# File 'lib/jms/session.rb', line 274

def temporary_queue(&block)
  q = create_temporary_queue
  if block
    begin
      block.call(q)
    ensure
      # Delete Temporary queue on completion of block
      q.delete if q
      q = nil
    end
  end
  q
end

#temporary_topic(&block) ⇒ Object

Return a temporary topic The temporary topic is deleted once the block completes If no block is supplied then it should be deleted by the caller when no longer needed



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# File 'lib/jms/session.rb', line 300

def temporary_topic(&block)
  t = create_temporary_topic
  if block
    begin
      block.call(t)
    ensure
      # Delete Temporary topic on completion of block
      t.delete if t
      t = nil
    end
  end
  t
end

#topic(topic_name, &proc) ⇒ Object

Return the topic matching the topic name supplied Call the Proc if supplied



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# File 'lib/jms/session.rb', line 290

def topic(topic_name, &proc)
  t = create_topic(topic_name)
  proc.call(t) if proc
  t
end