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Short note: Flow of object

Short answer

Object flow in activity diagrams passes data objects between actions, showing state changes. An object rectangle and dashed arrow denote flow. It reveals data dependencies and helps identify classes and their states as objects move through the workflow.

Write a short note on Flow of object [?].

(Interpreted as object flow in an activity diagram.)

An object flow shows that an object (data or product) is produced or consumed by an action, and passes from one activity to the next. In an activity diagram a control flow only says "what happens next", while an object flow also says "what is passed".

Notation

  • The object is drawn as a rectangle with the name (and state in brackets): Order [placed].
  • An object flow is a dashed or solid arrow from the action producing the object to the object node, and another arrow from the object to the action consuming it.
  • Input and output pins on actions can show the same idea.
 [ Take Order ]
        |
        v
   +----------+
   |  Order   |
   | [placed] |
   +----------+
        |
        v
 [ Validate Order ]
        |
        v
   +-----------+
   |  Order    |
   | [verified]|
   +-----------+
        |
        v
  [ Ship Order ]

Uses

  • Shows how an object changes state as it moves through the workflow.
  • Shows data dependencies between activities.
  • Helps identify classes and their state diagrams, since the object states appear in the flow.

The same object may appear several times in different states to show its life cycle within the process.

✓ Answer checked by Claude Opus 5.5 (high effort)

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