UML Weekend Crash Course™ - To Parent Directory

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Sunday Morning
The second scenario, modeled in Figure 23-4, shows the receiving event. There is only
one event hitting the Product lifeline, so I identify two candidate states: the one before the
event and the one after. The event receive(location) becomes the reason for the transition
from On Order to Inventoried.
:ReceivingClerk :Shipment :Product
1:getNextProduct()
2:return Product
On Order
3:receive(location)
On Order
receive(location)
4:return true
Inventoried
Inventoried
Figure 23-4 Finding the transition events and candidate states for Scenario 2
If you’re struggling with a name for the state, try to identify the attributes
that change in the transition and use them and their values as the descriptors.
For example, if the cancelled date is set, then call it Cancelled; if the
Tip
product was placed into inventory by entering a location value in the location
attribute, call it Inventoried.
The third scenario, in Figure 23-5, shows the Product being sold. Before the sell event,
the Product was sitting in inventory. In fact, if it were not in inventory, I could not sell it.
So again, I identify two states and use the incoming event sell as the transition event
between the two states.