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| Annex 2 | |||
| 2.1 The Complex Method GRAPES |
GRAPES - Graphical Engineering System
 Contents
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1 Brief Description
GRAPES (Graphical Engineering System) is a system development method designed to support the entire software development process, from the problem analysis to the implementation.
The modeling language GRAPES-86 is the central part and makes it possible to specify structure, behavior, and data from information processing systems, in particular from distributed systems like company organizations and network architectures.
GRAPES-86 has a formal, defined text and graphic syntax, therefore it can be statically assessed. Furthermore, GRAPES-86 includes a dynamic processing model. Thus the dynamic behavior of GRAPES models can be simulated and analyzed.
GRAPES supports concurrency, synchronous and asynchronous communication concepts (structured process descriptions), entity relationship modeling, and object-oriented concepts like modularization and strong typing.
To represent models with GRAPES, diagrams with a limited supply of graphical symbols are utilized. These diagrams make it possible to map essential characteristics of a total system - structure, processes, and information - in form of models and to improve them successively. The various diagram types cover several aspects of the system description. Next the methodical components are briefly described:
- Structure and Communication Modeling
CD
Communication diagrams are used to describe the decomposition of an object or object type into subobjects by means of communication paths.IT
An interface table describing the structure of the communication path in form of channels and corresponding data types has been allocated to each communication path of a communication diagram. - Behavior and Process Modeling
PD
The behavior of process objects (processes) as well as procedures and functions are defined in process diagrams.DT
Data tables are used for the declaration of constants and variables on which processes, procedures, functions, or modules are applied.SD
Specification diagrams are used to describe interfaces. In this connection it is possible to represent the call interfaces (the parameters) of procedures or functions and the export interfaces of modules. - Data Modeling
DD
Data structure diagrams are used to model the data structure. Self-defined data types can be described.ER
Entity Relationship diagrams are used to model data. Logical database modeling and normalization are supported. - Representation of the Declaration Hierarchy
HD
The hierarchical structure of a model is represented in hierarchy diagrams. Furthermore, the domains of names and declarations are specified according to the scope rules of GRAPES-86. In particular, they reflect the functional decomposition of the model. - Simulation
The uniform model representation on the basis of adjusted description techniques facilitates the investigation of consistency rules and the quantitative as well as qualitative simulation. GRAPES especially allows the investigation of the time and load behavior of a model.
A description of the lifecycle process model of SNI can be found in the process manual for the generation of application software and the realization of projects /PHB, 1991/. The GRAPES method is based on a model cycle, beginning with the actual model and continuing with the planned model, the user-level, preliminary and detailed model up to the DP model. For more information about the GRAPES method also see the method comparison GRAPES/SSADM in /Duschl, 1992/ realized by SNI and CCTA.
GRAPES is part of the open, integrated process engineering method DOMINO. Aspects of the system development like e. g. project management, documentation system, etc. that are not covered by GRAPES are completed in DOMINO with methods and tools adjusted to GRAPES.
GRAPES was developed by Siemens Nixdorf Informationssysteme AG (SNI) or respectively Siemens AG and applied in a large number of projects. The method is constantly upgraded and adjusted to modern software engineering technologies.
2 Tabular Comparison
The following table compares the basic methods of the GD 251 with the methodical components of GRAPES. In the case where there is no entry in the right column of the table, GRAPES has no corresponding component. Otherwise an entry refers to the corresponding part in the GRAPES literature. Section 3 of the comparison contains explanations for the entries. Entries identified with (*) refer to basic methods completely covered by GRAPES. These are not further explained in section 3.
3 Specification of the Allocation
| Method | Corresponding Component in GRAPES | Explanation |
|---|---|---|
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TREE Tree Diagram | /Held, 1990/ chap. 9: Hierarchy Diagram | The hierarchy diagram documents the decomposition structure into the components of a system by means of a tree form. It illustrates the functional hierarchy and the allocated diagrams like process diagrams, data tables, specification diagrams, etc. |
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FCTD Functional Decomposition | /Held, 1990/ chap. 5 | Based on the model structure described in the hierarchy diagram a functional decomposition can be extracted by reducing the hierarchy diagram to the object relationships. A detailed representation can be found in the Information and Function Modeling with GRAPES /Held, 1991a/. |
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CFM Control Flow Modeling | /Held, 1990/ chap. 5 | General control flows can be modeled by means of process diagrams. The interaction of the processes can also be described by process diagrams, i. e. if this representation is required. The control flow of a model is completely defined by the process descriptions of its elementary objects and by the communication relationships (synchronous/asynchronous), though. The interaction of the individual processes (activation, deactivation) must be collected in separate diagrams, according to CFM. |
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ODT Object Design Technique | /Held, 1990/ chap. 2 |
The system view of GRAPES is the hierarchical decomposition of the system into a set of communicating objects. Objects are either composed of other communicating objects (structure object), elementary objects with local data storage and locally defined input/output behavior (process objects), or data management objects the content of which is explained by means of an E/R diagram (data stores). Furthermore, object types can be declared for multiple use or reuse. Even though primarily intended for the design phase it is also applied for the modeling during the analysis phase. In order to further develop the object-oriented approach in GRAPES-86 it is referred to the book Object-Oriented System Development /Held, 1991a/. |
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STAT Static Analysis | /Held, 1990/ chap. 3 + 5.2 + 6.7 + 6.9 + 7.5 | The syntax and semantics of the modeling language is formally defined. Thus it is possible to statically check the syntax as well as the model consistency of the three system views structure, behavior, and data automatically. This comprises the existence of sources and sinks of all communication paths and the consistent declaration and utilization of variables, parameters, and its data types. /GRAPES-SD, 1993/ contains a detailed description of the realization of static analysis and the corresponding results. |
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STRD Structured Design | /Held, 1990/ chap. 6.6 | GRAPES contains mechanisms to specify and define modules (specification diagrams). They allow the specification of procedures, functions, and submodules with its formal parameters and data types. The module hierarchy has to be additionally represented in Structure Charts, according to STRD. |
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SBM System Behavior Models | /Held, 1990/ chap. 2 and chap. 6.7 | GRAPES models a system composed of cooperating objects. The system behavior is derived from the interaction of the elementary process objects. It is based on an operational semantic network of communicating, upgraded state automata. GRAPES processes are special because of local data, special branching (parallel branching, selective waiting with fairness condition) and because each connection has its own waiting queue. |
4 Literature
/Duschl, 1992/ SSADM & GRAPES, Two Complementary Major European Methodologies for Information Systems Engineering
/GRAPES-RDDG, 1993/ GRAPES RDDG, Benutzerhandbuch V 1.0
/GRAPES-SD, 1993/ GRAPES SD, Benutzerhandbuch V 2.0
/GrapSim, 1993/ GRAPES-Simulator V 1.0. Benutzerhandbuch
/Held, 1990/ Sprachbeschreibung GRAPES
/Held, 1991a/ Objektorientierte Systementwicklung
/PHB, 1991/ Prozeßhandbuch für die Erstellung von Anwendersoftware und Realisierung von Projekten
