Sequence Node Sequence Node (Action)

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A constraint is a condition or restriction expressed in natural language text or in a machine readable language for the purpose of declaring some of the semantics of an element.

An action is a named element that is the fundamental unit of executable functionality.

The execution of an action represents some transformation or processing in the modeled system, be it a computer system or otherwise.

An action represents a single step within an activity, that is, one that is not further decomposed within the activity.

An action has pre- and post-conditions.

A structured activity node is an executable activity node that may have an expansion into subordinate nodes as an activity group. The subordinate nodes must belong to only one structured activity node, although they may be nested. Because of the concurrent nature of the execution of actions within and across activities, it can be difficult to guarantee the consistent access and modification of object memory. In order to avoid race conditions or other concurrency-related problems, it is sometimes necessary to isolate the effects of a group of actions from the effects of actions outside the group. This may be indicated by setting the mustIsolate attribute to true on a structured activity node. If a structured activity node is "isolated," then any object used by an action within the node cannot be accessed by any action outside the node until the structured activity node as a whole completes. Any concurrent actions that would result in accessing such objects are required to have their execution deferred until the completion of the node.

A constraint is a condition or restriction expressed in natural language text or in a machine readable language for the purpose of declaring some of the semantics of an element.

A sequence node is a structured activity node that executes its actions in order.

[collapsed] [expanded] Properties

Mandatory

Rules

[collapsed] [expanded] Parent

An element of one of the following kinds:

[collapsed] [expanded] Nested Elements

Rules

[collapsed] [expanded] Outgoing

Rules

[collapsed] [expanded] Incoming

Rules

[collapsed] [expanded] Relations

Rules

[collapsed] [expanded] Usage