1、INTERNATIONAL STANDARD ISOJIEC 11411 First edition 1995-04-01 Information technology - Representation for human communication of state transition of software Technologies de /information - t?epr b) defines the notation of state transition elements; c) specifies a set of state transition elements. IN
2、TERNATIONAL STANDARD WMEC ISO/IEC 11411 : 1995(E) Information technology - Representation for human communication of state transition of software 1 Scope The underlying concept of this International Standard is that diagrams and symbols defined herein can be helpful in representing software function
3、s and transitions and in improving human communication. The areas covered by this International Standard are development, communication and review of software requirement analysis and design. This International Standard is effective in the following fields of software. Interactive software -To descr
4、ibe the representation of functions and transitions on screens. Data communication software -To describe communication protocols and corresponding actions. Language/command -To describe the syntax. 2 Definitions For the purposes of this international Standard, the following definitions apply. 2.1 st
5、ate : A state is the unique value that represents the stage of progress of software in its execution. The state shall have a unique name as its identifier which is called state name. 2.2 transition : A transition is a change from one state to another state or the same state. A transition takes place
6、 when a condition is satisfied. An action may take place along with the transition. Formally, a transition consists of three parts: - direction part; - condition part; - action part. The direction oart in turn consists of two state identifiers: - previous state identifier, pointing to the previous s
7、tate; - next state identifier, pointing to the next state. The condition part expresses the condition that must be satisfied for the action to take place and the change from one state to another. If more transitions are defined to change from one state to another state or the same state, they shall
8、be mutually exclusive. The action part represents the action which is performed by the software according to the condition. The action may be any processing or may be nil. 3 S pecification 3.1 Specification of state States are a) Initial state One and only one state is initial. In the initial state,
9、 the software starts its activity. The initial state must be the previous state of at least one transition. b) Final state One or more states can be the final state. In final states the software terminates its activity. Each final state must be the next state of at least one transition. c) Initial/f
10、inal state The initial state can be the final state. In this case, the software terminates its activity and the activity may or may not be immediately restarted. The initial/final state must be the previous state of at least one transition and the next state of at least one transition. d) Intermedia
11、te state A state that is not initial, not final, and not initial/final is called an intermediate state. It must be the next state of at least one transition from another state and the previous state of at least one transition to another state. 1 ISOhEC 11411 : 1995(E) 0 ISO/IEC 3.2 Specification of
12、transition Transitions are a) Transition to another state This transition indicates the change from one state to another state. The previous state and the next state identifiers in the direction part of such a transition designate different states. b) Transition to the same state This transition ind
13、icates the change from one state back to the same state. The previous state and the next state identifiers in the direction part of such a transition designate the same state. 3.3 Usage of state and transition Description of the state transition of software shall obey the following conditions at the
14、 same time. a) One and only one initial state exists. b) Zero or more final state(s) exist(s). c) One or more transition(s) exist(s). d) A previous state and a next state in each transition exists. 4 State diagram 0 State name b) Final state The charting notation of the final state is as follows c)
15、Initial/final state The initial state can be the final state at the same time. In this case, the charting notation of the state is as follows. 0 State 0 name OK d) Intermediate state The charting notation of an intermediate state is as foilows. State 0 name 4.1 Concept 4.1.2.2 Transition 4.1 .l Diag
16、ram In the state diagram, state and transition are presented by symbols and texts. The state diagram represents permissible or defined changes of state. 4.1.2 Symbols 4.1.2.1 State Transition is presented by an arrow and text. The text includes condition part and action part. There should be a clear
17、 delimiter between condition part and action part, e.g. slash or horizontal line. a) Transition to another state The charting notation for a transition from one state to another is as follows. Condition part /Action part A state is presented by a circle and text. a) Initial state The charting notati
18、on of the initial state is as follows. 2 0 ISOAEC l!SO/IEC 11411 : 1995(E) The condition part and action part should be described near the transition arrow. The description of the transition may interrupt the arc. b) Transition to the same state The charting notation for a transition from a state to
19、 the same state is as follows. Condition part / Action part r Condition part Action part 0 The condition part and action part should be described near the transition arrow. The description of the transition may interrupt the arc. 4.2 Conventions Diagraming conventions : The following are examples of
20、 allowed variations of charting notations. a) Various shaped state symbols Various state symbols whose basic shapes are shown as follows may be used. 0-n In the case of the rectangle, the ratio of length and breadth is not defined. The way to represent initial, final and initial/final states in any
21、basic shape is the same as shown in 4.1.2. State + (identifier) incoming connector (identifier) p 4.3.2 Forms This International Standard does not require a specific form sheet or template. It is possible to describe a state diagram defined in this International Standard using only the usual straigh
22、t and circle ruler. b) A filled or outlined arrow pointing to or from symbols may be used as the symbol of the initial, final, initial/final state. as follows. 3 ISO/IEC 11411 : 1995(E) o ISO/IEC 5 State table 5.1 Concept b) Final state The charting notation of a final state is as follows. 5.1 .l Di
23、agram State transition may be also represented by a table. States and conditions will be represented in rows and columns. Transitions are at the corresponding intersections. .* . In state table, a state has a state No. as an additional identifier of state. The state No. is a unique number such as se
24、rial number of state. 5.1.2 Symbols . . . . c) Initial/final state The initial state can be the final state at the same time. In this case, the charting notation of the state is as follows. 5.1.2.1 State a) Initial state The charting notation of an initial state is as follows. . . . . d) Intermediat
25、e state The charting notation of this state is as follows. o;:.:. . . . . . . . NOTE- In clause 5, the ellipsis (three dots) is used to show general solutions with an open number of repetition of symbols or a set of symbols as follows 5.1.2.2 Transition Transition is presented by an intersection. Ac
26、tion part and next state number are described in the intersection. 4 . 0 B 0 ISO/IEC ISO/IEC 11411 : 1995(E) a) Transition to another state The charting notation for a transition from one state to another is as follows. . a) Use of the state name as the next state identifier When it is easy to find
27、a state in a state table using state name, state name may be used instead of state No. as the next state identifier in the intersection. In this case, the state No. part defined in 5.1 .2.1 can be omitted. b) Omission of an action part in a transition The action part in the transition may be left bl
28、ank when there is no action executing with the transition or it is not necessary to show the action. 5.3 Usage and restrictions 5.3.1 Drawing Both hand-drawn symbols and machine-drawn symbols are the same as those specified in 5.1.2. . . 5.3.2 Forms . . The state No. and the next state No. designate
29、 different states. b) Transition to the same state In case of transition to the same state, the next state No. is the same as the original state No. 5.2 Conventions Diagraming conventions : The following are examples of permitted variations of charting notations. Positions of state and condition are
30、 interchangeable, and this International Standard does not require a specific form sheet. p . . . . Invoke / TERM ! Read Index Terminate INDEX / END/ Write File Read on, 1974, McGraw-Hill Inc. 2. Paul T Ward, Stephen J Mellor, Structured development for real-time systems, 1985, Prentice Hall. 3. Edw
31、ard Yourdon, Modern sfructuredana/ysis, 1989, Yourdon Press. 4. Wilfried Brauer, Net theory andapplication, Proceedings of the advanced course on general net theory of processes and systems, Hamburg, October 1979, Springer. Users of this International Standard can refer to two other standards concer
32、ning state transition based techniques: 1. CCITT Rec. Z. 100 and Z. 120 CMTSpecification and Description Language (SDL). (contains agraphical representation called SDL-GR) 2. IS0 9074 : 1989 Information processing systems- Open Systems Interconnection- Estelle ; A formal description technique based
33、on extended state transition model. (commonly referred to as ESTELLE) NOTE- SDL-GR is mainly used in the telecommunications field and includes rich facilities specific to that field. This standard is more general and may become the base of SDL-GR. ISO/IEC 11411:1995(E) Q ISO/IEC ICS 35.080 Descriptors: data processing, computer software, communication procedure, symbols, charts, diagrams. Price based on 8 pages
