The following diagram, based on Figure 7-1 appearing on p. 102 of the UML User Guide, illustrates an interaction diagram with an external actor.

## Diagram

UML User Guide: Figure 7-1, p. 102

## Diagram Source Code

# UML User Guide Figure 7-1. .PS

copy "sequence.pic";

actor(A,""); object(T,":OTaker"); object(F,":OFulfill"); step();

message(A,T,"submitOrder"); message(T,F,"placeOrder"); message(F,A,"acknowledgeOrder");

step(); complete(A); complete(T); complete(F);

.PE