Connecting message flow nodes

When you include more than one node in your message flow, you must connect the nodes to indicate how the flow of control passes from input to output. The nodes can be built-in nodes, user-defined nodes, or subflow nodes.

Before you begin

Complete the following tasks.

About this task

Your message flow might contain just one MQInput node, one Compute node, and one MQOutput node. Or it might involve a large number of nodes, and perhaps embedded message flows, that provide a number of paths through which a message can travel depending on its content. You might also have some error processing routines included in the flow. You might also need to control the order of processing.

You can connect a single output terminal of one node to the input terminal of more than one node (this is known as fan-out). If you do this, the same message is propagated to all target nodes, but you have no control over the order in which the subsequent paths through the message flow are executed (except with the FlowOrder node).

You can also connect the output terminal of several nodes to a single node input terminal (this is known as fan-in). Again, the messages that are received by the target node are not received in any guaranteed order.

When you have completed a connection, it is displayed as a black line, and is drawn as close as possible to a straight line between the connected terminals. This behavior might result in the connection passing across other nodes. To avoid this problem, you can add bend points to the connection.

To view metadata information for a node, subflow, or connection:
  1. Switch to the Integration Development perspective.
  2. Open a message flow.
  3. In the Message Flow editor, hold the mouse pointer over a node, a subflow, or a node connection in the open message flow by placing the mouse over the element.
A custom tooltip is displayed below the element.
  • To turn the pop-up window into a scrollable window, press F2.
  • To hide the pop-up window, either press Esc or move the mouse away from the node.

If you define a complex message flow, you might have to create a large number of connections. The principle is the same for every connection. You create connections either by using the mouse, or by using the Terminal Selection dialog. See Creating node connections with the mouse and Creating node connections with the Terminal Selection dialog box for more information.