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Overview

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Section 1

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Sending and Receiving from External Applications

This section describes how to send to Talon applications from non Talon applications and from Talon application to non Talon applications over solace. The sections below utilize the ADM generated messages for convenience, but this is not required. For example, if you your messages are encoded in protobuf (or Xbuf) you could encode/decode the message yourself without using ADM. One such example of this might be if you were using C and generated protobuf message from the IDL generated by ADM.

Sending Messages To Talon

The platform's JMS binding encodes a serialized message payload in a bytes message and sets metadata fields in its jms headers. The following example show

// populate a message
OrderEventMessage orderEvent = OrderEventMessage.create();
orderEvent.setOrderId(1);

// serialize the payload to a byte buffer
byte [] serializedPayload = view.serializeToByteArray();

// prepare JMS message
javax.jms.Message message = null;
if(view.getEncodingType == MessageView.ENCODING_TYPE_JSON) {
  message = session.createTextMessage();
  ((TextMessage)message).setText(new String(serializedPayload));
}
else {
   message = session.createBytesMessage();
   ((Bytes)message).setBytes(serializedPayload);
}
// prepare message metadata
MessageMetadata metadata = MessageMetadataFactory.getInstance().createMessageMetadata();
metadata.serializeV2(view.getMessageEncodingType(),
                     view.getVfid(),
                     view.getType(),
                     0,  // message sender id
                     0,  // message flow
                     0,  // message sequence number (unsequenced)
                     -1, // channel id (unspecified)
                     XString.create("order-events"));

// The jms binding decomposes metadata into message properties:
message.setBooleanProperty(JmsMessageBusBinding.SMA_METADATA_PRESENT_JMSPROP, true);
message.setByteProperty(JmsMessageBusBinding.SMA_METADATA_VERSION_JMSPROP, (byte)metadata.getVersion());
message.setByteProperty(JmsMessageBusBinding.SMA_METADATA_ENCODING_JMSPROP, metadata.getMessageEncodingType());
message.setShortProperty(JmsMessageBusBinding.SMA_METADATA_VFID_JMSPROP, metadata.getMessageViewFactory());
message.setShortProperty(JmsMessageBusBinding.SMA_METADATA_VTYPE_JMSPROP, metadata.getMessageViewType());
message.setIntProperty(JmsMessageBusBinding.SMA_METADATA_SENDER_JMSPROP, metadata.getMessageSender());
message.setIntProperty(JmsMessageBusBinding.SMA_METADATA_FLOW_JMSPROP, metadata.getMessageFlow());
message.setLongProperty(JmsMessageBusBinding.SMA_METADATA_SNO_JMSPROP, metadata.getMessageSno());
message.setShortProperty(JmsMessageBusBinding.SMA_METADATA_CHID_JMSPROP, metadata.getMessageChannelId());
message.setStringProperty(JmsMessageBusBinding.SMA_METADATA_CHNAME_JMSPROP, metadata.getMessageChannelName());

// send 
Topic topic = session.createTopic("order-events");
messageProducer.publish(topic, message, DeliveryMode.PERSISTENT, 0, 0);

// dispose
orderEvent.dispose();
metadata.dispose();

Receiving Messages from Talon

The following code sample shows how an external application using the JMS api directly can unpack a message sent over the platform's built in JMS binding and materialize it into a message view.

public void onMessage(javax.jms.Message message) {
  // extract sma metadata
  final boolean isMetadataPresent = message.getBooleanProperty(SMA_METADATA_PRESENT_JMSPROP);
  if (!isMetadataPresent) {
     // not an x message. 
     handleNonXMessage(message);
  }
  final byte encodingType = message.getByteProperty(SMA_METADATA_ENCODING_JMSPROP);
  final short vfid = message.getShortProperty(SMA_METADATA_VFID_JMSPROP);
  final short vtype = version > MessageMetadata.V1 ? message.getShortProperty(SMA_METADATA_VTYPE_JMSPROP) : 0;
 
  // extract payload
  Object payload = null;
  if(message instanceof TextMessage) {
     payload = ((TextMessage) message).getText(); 
  }
  else if(message instanceof BytesMessage) {
     payload = ((BytesMessage) message).getBytes(); 
  }
  else {
    handleNonXMessage(message);
    return;
  } 
 
  // lookup factory
  // (assumes that view factory have already been registered)
  MessageViewFactory factory = viewFactoryRegistry.getMessageViewFactory(vfid);
  if (factory != null) {
    MessageView view = factory.wrap(vtype, encodingType, payload);
    if(view instanceof OrderEventMessage) {
      handleOrderEvent((OrderEventMessage) message);
    }
  }
  else {
    handleNonXMessage(message);
    return;
  }
}