Model Parts, Diagrams, Dictionary Items, and Properties > Dictionary items > Channel (dictionary item)
Channel (dictionary item)
For automation interface information about a Channel, see Channel (automation interface).
A Channel is used on a Concurrency Diagram to transfer data between objects communicating asynchronously. The data is deposited in a buffer and accessed on a first-in-first-out basis
Channels are often used when it is important that every message sent is consumed and dealt with. For example, messages that change the state of some object must be processed, or the object may remain in the incorrect state and process further messages incorrectly. Multi-message buffers allow the storage of many messages which allows the consumer to 'lag behind' when perhaps it is getting less processing time than more important tasks, and then to catch up during quiet periods.
You can create a Channel through the context menu of a Package: right-click the Package, point to New, point to Proprietary, point to Concurrency, and then click Channel. In addition, you can create a Channel through a Concurrency Diagram.
When used on a diagram, a Channel's notation is as follows:
In the Modeler panes, a short-cut symbol on the Channel's icon indicates that the item is a stub. For more information, see Stubs.
The following sections provide information about how a Channel is used in the model. For more information about a property, item, model part or diagram, click it.
In addition to the standard properties, a Channel has these properties:
Number of Instances
Width (Size through the automation interface)
The Class box on the Options tab of a Channel's Property Pages shows the Class, Data Type or Interface that owns the Operations that implement the Channel.
Owned by
Dependency - The Dependency is owned jointly by the Channel and the other associated item. The access permissions you have to a Dependency are determined by the access permissions of the dependent item.
Defined in these parts of the model
Concurrency Model
Shown on these diagrams
Concurrency Diagram
Variant Diagram
Can be linked to these dictionary items
In addition to the owning Package or Model, a Channel can be linked to the following items.
Class - The Class contains the Operations required to implement the Channel (drag Class to Channel symbol on diagram).
Data Type - The linked Data Type contains the Operations required to implement the Channel (drag Data Type to Channel symbol on diagram).
Interface - The linked Interface contains the Operations required to implement the Channel (drag Interface to Channel symbol on diagram).