Annex 1
		4.15 Interface PCODE-PIM

Contents		1 Characterization of the Interface 2 Example 3 Tool Support 4 Literature

1 Characterization of the Interface

In the PIM process interaction diagrams, certain courses of the modeled processes are illustrated. The sequence of the signal exchange between the processes includes a causal logic specification of the behavior, i. e. this behavior is explicitly requested by the software. The detailed specification of the behavior in the detailed SW design via PCODE must take these causal logic specifications into consideration, i. e. the sequences formulated in PCODE must be consistent to the sequences specified in the PIM.

2 Example

Figure 4.21: Example Process Interaction diagram for telephone call

     process PHONE_LINE 
     ...
     when STATE = IDLE
       accept dial request
          start dial tone at Caller
          set STATE = DIAL_TONE
       end
     when STATE = DIAL_TONE
       accept one digit
          stop dial tone at Caller
          set STATE = DIALING
       end
     when STATE = DIALING
       repeat
         accept digit
       until valid number is received
       start ringing at Callee
       start ringing tone at Caller
       ...

Explanation:

The listed pseudocode (see Figure 4.22) accurately generates the preset sequence of the signals by permitting only certain states for the corresponding actions or by realizing the actions itself (expressed by "when..." ). In this connection, the PCODE notation follows Ada.

3 Tool Support

4 Literature

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