Object nodes

In activity diagrams, an object node is an abstract activity node that helps to define the object flow in an activity. An object node indicates that an instance of a classifier might be available at a particular point in the activity.

The following table describes the types of object nodes that you can use to model object flow in activity diagrams.

Object node type Description Icon
Activity parameter This node specifies the input and output parameters for the activity. A small rectangle, called Activity parameter, is inserted into the left edge of an activity frame. The header of the activity frame contains the name Activity2.
Central buffer This node is used to consolidate data from several sources and destinations. Central buffer nodes do not connect directly to actions. A rectangle contains the word centralBuffer in double angle brackets.
Data store This node is used to model data flow in which the data is persistent. A rectangle contains the word datastore in double angle brackets.
Input pin This node represents the input parameters on an action. The input pin holds the input values that are received from other actions. A rectangle with rounded corners contains the name Operation1. A small square is attached to the left side of the operation and contains an arrowhead that points to the operation.
Output pin This node represents the output parameters on an action. The output pin holds the output values that an action produces. Object flow edges deliver the output values to other actions. A rectangle with rounded corners contains the name Operation1. A small square is attached to the right side of the operation and contains an arrowhead that points away from the operation.

Related concepts
Activities
Structured activities
Actions
Call behaviors
Call operations
Control nodes
Activity edges
Feedback
(C) Copyright IBM Corporation 2004, 2005. All Rights Reserved.