Passthrough node

This topic contains the following sections:

Purpose

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Use the Passthrough node to enable versioning of a subflow at run time. The Passthrough node allows you to add a label to your message flow or subflow. By combining this label with keyword replacement from your version control system, you can identify which version of a subflow is included in a deployed message flow. You can use this label for your own purposes. If you have included the correct version keywords in the label, you can see the value of the label:
  • Stored in the broker archive (BAR) file, using the mqsireadbar command
  • As last deployed to a particular broker, on the properties of a deployed message flow in the Message Brokers Toolkit
  • In the run time, if you enable user trace for that message flow.

The Passthrough node does not process the message in any way. The message that it propagates on its out terminal is the same message that it received on its in terminal.

The Passthrough node is represented in the workbench by the following icon:

Passthrough node icon

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Using this node in a message flow

Use this node to identify a subflow. For example, if you develop an error processing subflow to include in several message flows, you might want to modify that subflow. However, you might want to introduce the modified version initially to just a subset of the message flows in which it is included. Set a value for the instance of the Passthrough node that identifies which version of the subflow you have included.

Configuring the Passthrough node

When you have put an instance of the Passthrough node into a message flow, you can configure it. Right-click the node in the editor view and click Properties. The node's basic properties are displayed.

All mandatory properties for which you must enter a value (those that do not have a default value defined) are marked with an asterisk on the properties dialog.

Configure the Passthrough node as follows:

  1. Specify in Label the identifier for this node. Enter a value that defines a unique characteristic, for example the version of the subflow in which the node is included.
  2. Select Description in the properties dialog navigator to enter a short description, a long description, or both.
  3. Click Apply to make the changes to the Passthrough node without closing the properties dialog. Click OK to apply the changes and close the properties dialog.

    Click Cancel to close the dialog and discard all the changes that you have made to the properties.

Terminals and properties

The Passthrough node terminals are described in the following table.

Terminal Description
In The input terminal that accepts a message for processing by the node.
Out The input terminal that delivers a message to the subflow.

The following tables describe the node properties; the column headed M indicates whether the property is mandatory (marked with an asterisk on the properties dialog if you must enter a value when no default is defined), the column headed C indicates whether the property is configurable (you can change the value when you add the message flow to the bar file to deploy it).

The Passthrough node Basic properties are described in the following table.

Property M C Default Description
Label No No   The label (identifier) of the node.

The Passthrough node Description properties are described in the following table.

Property M C Default Description
Short Description No No   A brief description of the node.
Long Description No No   Text that describes the purpose of the node in the message flow.
Related concepts
Message flows overview
Related reference
Input node