BLOB domain

IBM® Integration Bus uses the BLOB parser to process messages that belong to the BLOB domain.

A BLOB message is handled as a single string of bytes, and although you can manipulate it, you cannot identify specific pieces of the byte string in the way that you can with messages in other domains. The BLOB parser does not create a message tree structure in the same way that other parsers do. It creates a simple tree with a root element BLOB that has a child element, also called BLOB, that contains the message bit stream.

The TX Map node can consume and create messages in the BLOB domain. However, the message must be modeled using a type tree so the map can interpret the structure of the BLOB message.

To create a message flow that uses the TX Map node to create or consume messages in the BLOB domain, do the following steps within the IBM Integration Toolkit:

  1. In the Transformation Extender Development perspective, use Type Designer to model the message format as a type in a type tree (.mtt) file.
  2. In the Transformation Extender Development perspective, use Map Designer to create a map, and add input or output cards as required. In the New Card dialog, select the type tree (.mtt) file as the Type tree, and the type as the Type.
  3. Switch to the IBM Integration Development perspective, and create a message flow containing a TX Map node that uses your map.
    1. If the message is consumed by an input card, configure the input node of the message flow to specify the Message Domain as BLOB.
    2. If the message is created by an output card, configure the corresponding TX Map node output terminal to specify the Message Domain as BLOB, complete the Message Set property, and set the Encoding and Coded Char Set ID properties to match the byte order (endianness) and character set of the output data from the map.
  4. Complete the message flow, and deploy it to the broker.
At run time, if the message is to be consumed by an input card, the input node of the message flow starts the BLOB parser, which creates a simple message tree from the message bit stream. The TX Map node receives the BLOB message tree, extracts the BLOB bit stream element, and passes it to the input card. When the map runs, it parses the bit stream using the type tree.

At run time, if the message is to be created by an output card, when the map runs, it creates a bit stream. The TX Map node starts the BLOB parser to create a simple message tree from the bit stream, and propagates it to the next node in the message flow. The output node of the message flow starts the BLOB parser, which extracts the BLOB bit stream element.

The map is built using the type tree, and at run time, the map itself parses the message bit stream on input, and serializes it on output, using the type tree.