Identifying states

After all of the detailed sequence diagrams are complete, you can identify the key states in the object lifecycle.

The following figure shows an example of the key states for the main payment transaction n of the sample.

Figure 1. Sample application key states for the main payment transaction

At first, it might be difficult to identify and name these states. The state of an object reflects the current position in the lifecycle of the object. Typically, this relates to something that is happening, something that must happen before proceeding (that is, while waiting), or to an outcome. The names of states typically end with the letters ing or ed.

Identification of states can be an iterative process.

Table 1. Key states for the main payment transaction
Lifecycle point	State	Description
S1	Transaction Mapped	Initial state.
S2	Transaction Validating	Transient state to indicate that validation is in progress.
S3	Wait for Liquidity Response	Indicates that a request was sent and is waiting for a response.
S4	Wait for Gateway Ack	Indicates that a request was sent and is waiting for a response.
S5	Wait for Client Ack Sent	Indicates that an acknowledgment is being sent to the client.
S6	Transaction Complete	Indicates that a payment transaction is finished. This is a final state.
S7	Waiting for Repair	Indicates that a request was sent and is waiting for a response.