Model Parts, Diagrams, Dictionary Items, and Properties > Dictionary items > Read extent action (dictionary item)
Read extent action (dictionary item)
For automation interface information about a Read Extent Action, see Action node (automation interface). For automation interface purposes, a Read Extent Action is an Action Node that has its Node Type set to Read Extent Action.
A Read Extent Action is an action that retrieves the current instances of a classifier. The extent of a classifier is the set of all instances of a classifier that exist at any one time.
Create a Read Extent Action through a Modeler explorer pane or an Activity Diagram:
• In a Modeler pane, right-click an Activity or Structured Activity Node, and select New > Action Node > Read Extent Action.
• On an Activity Diagram tab: click the Read Extent Action button, and then click in free space or inside an Activity Partition, Interruptible Activity Region or Structured Activity Node.
To access the Read Extent Action button, click the arrow next to the Read Self Action button, and then select Read Extent Action button..
When you create a Read Extent Action, you are prompted to select or create the Class, Data Type, Interface or Signal that is read by the action. After creating a Read Extent Action you cannot link that Read Extent Action to a different Class, Data Type, Interface or Signal. You can view which Class, Data Type, Interface or Signal is linked to a Read Extent Action through the Read Extent Action's property pages: on the Items tab, select Linked Item.
On creation of a Read Extent Action, Modeler creates an Output Pin named Result Pin. The Output Pin's data type is the source item of the Association that is linked to the Read Extent Action. You cannot delete this Output Pin, and you cannot create any other Output Pins or Input Pins on a Read Extent Action.
When used on an Activity Diagram, a Read Extent Action's notation is as follows.
The View Options on an Activity Diagram allow you to show or hide the Name, Action Type and Linked Item Name. By default, the Action Type and Linked Item Name are shown. The view options are set through the Action Node entry. See Action node view options - activity diagram.
On an Activity Diagram, you can double-click a Read Extent Action to open child diagrams of the linked Class, Data Type, Interface or Signal.
On an Activity Diagram, you can populate a Read Extent Action's missing Activity Flows, Output Pins, Comments and Constraints: right-click the Read Extent Action, point to Populate, and then click the appropriate command.
In the Dictionary pane, Read Extent Actions are listed in the UML\Action Nodes folder.
In the Modeler panes, a short-cut symbol on the Read Extent Action's icon indicates that the item is a stub.
The following sections provide information about how a Read Extent Action is used in the model.
Properties
In addition to the standard properties a Read Extent Action has these properties:
Visibility
Owned by
Activity - The Activity that scopes the Read Extent Action.
Structured Activity Node - Applies only when the Read Extent Action is scoped directly to a Structured Activity Node.
Owns
Comment
Constraint
Control Flow - The Control Flow is owned jointly by the Read Extent Action and the associated item. The access permissions you have to a Control Flow are determined by the access permissions you have to its source item.
Dependency - The Dependency is owned jointly by the Read Extent Action and the other associated item. The access permissions you have to a Dependency are determined by the access permissions of the dependent item.
Exception Handler - The Exception Handler is owned jointly by the Read Extent Action and the associated item. The access permissions you have to an Exception Handler are determined by the access permissions you have to its source item.
IO Flow - The IO Flow is owned jointly by the Read Extent Action, the IO Flow's other linked item and the IO Flow's IO Item.
Output Pin - Only the Result Pin that Modeler creates on creation of the Read Extent Action.
Defined in these parts of the model
Activity Model
Shown on these diagrams
Activity Diagram
Variant Diagram
Can be linked to these dictionary items
In addition to the owning Activity or Structured Activity Node, a Read Extent Action can be linked to the following items.
Stereotype - To make a Read Extent Action valid for a Stereotype, set up Action Node a valid item type.
* 
Like most other items in a Model, a Read Extent Action can be linked to an Activity Partition, Comment, Frame Box, General Node, General Flow, General Flow Diagram Node, Constraint (applied), General Flow Diagram Flow or Swimlane.