Label node

This topic contains the following sections:

Purpose

Use the Label node in combination with a RouteToLabel node to dynamically determine the route that a message takes through the message flow, based on its content. The RouteToLabel node interrogates the LocalEnvironment of the message to determine the identifier of the Label node to which the message must next be routed.

Precede the RouteToLabel node in the message flow with a Compute node that populates the LocalEnvironment of the message with the identifiers of one or more Label nodes that introduce the next sequence of processing for the message.

Design your message flow such that a Label node logically follows a RouteToLabel node within a message flow, but do not physically wire it to the RouteToLabel node. The connection is made by the broker, when required, according to the contents of LocalEnvironment.

The Label node provides a target for a routing decision, and does not process the message it handles in any way. Typically, a Label node connects to a subflow that processes each message in a specific way, and either ends in an output node or in another RouteToLabel node.

The Label node can also be used as the target of a PROPAGATE statement, specified in a Compute or Database node.

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

Label node icon

Using this node in a message flow

Look at the Airline Reservations sample to see how you can use this node.

Configuring the Label node

When you have put an instance of the Label 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 Label node as follows:

  1. There is a single mandatory property for the Label node, Label Name, which identifies a target for a RouteToLabel node. Label Name must not be the same as the name of the instance of the node itself, and it must be unique within the message flow in which it appears. The name of the instance can be modified by the workbench if the subflow of which this Label node is a part is embedded into another message flow.
  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 Label 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 Label node terminals are described in the following table.

Terminal Description
Out The output terminal to which the message is routed.

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 Label node Basic properties are described in the following table.

Property M C Default Description
Label Name Yes No   An identifier for the node. It is used as a target for a message routed by a RouteToLabel node.

The Label 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