Expansion regions

• Flow finals- When have multiple tokens, flow can stop without activity stopping

• Flow final indicates termination of flow, not activity

• Time signal “Deadline for submission” triggers allocation of submitted papers to reviewers

• Each paper is reviewed by a reviewer and either accepted or rejected

• Reviewing done in parallel – indicated by keyword, <<concurrent>>

• If paper rejected, ends flow; otherwise, token added to output collection

• Output collection passed to “Publish accepted papers”

• Expansion region acts as a filter

• Use expansion regions when output of action triggers same sequence of actions to be performed on two or more objects

• Join specifications - Join emits token on output flow when token arrived on each input flow

• Sometimes want join to emit token when special conditions apply

• Can do this with a join specification

– Boolean expression must be true in order for token to be emitted on output flow

25. Main elements of communication diagram: definitions, description, examples.

Communication diagrams, a kind of interaction diagram, emphasize the data links between the various participants in the interaction. Instead of drawing each participant as a lifeline and showing the sequence of messages by vertical direction as the sequence diagrams does, the communication diagram allows free placement of participants, allows you to draw links to show how the participants connect, and use numbering to show the sequence of messages.

Figure 1 shows a communication diagram for the same centralized control interaction as in Figure 2. With a communication diagram, we can show how the participants are linked together.

As well as showing links that are instances of associations, we can also show transient links, which arise only the context of the interaction. In this case, the «local» link from Order to Product is a local variable; other transient links are «parameter» and «global».

Figure 1. Communication diagram for centralized control