Figure 3: ArchiMate Full Framework

      The ArchiMate language does not define a specific layer for information; however, elements from the passive structure aspect such as business objects, data objects, and technology objects are used to represent information entities. Information modeling is supported across the different ArchiMate layers.

3.6 Abstraction in the ArchiMate Language

      The structure of the ArchiMate language accommodates several familiar forms of abstraction and refinement. First of all, the distinction between an external (black-box, abstracting from the contents of the box) and internal (white-box) view is common in systems design. The external view depicts what the system has to do for its environment, while the internal view depicts how it does this.

      Second, the distinction between behavior and active structure is commonly used to separate what the system must do and how the system does it from the system constituents (people, applications, and infrastructure) that do it. In modeling new systems, it is often useful to start with the behaviors that the system must perform, while in modeling existing systems, it is often useful to start with the people, applications, and infrastructure that comprise the system, and then analyze in detail the behaviors performed by these active structures.

      A third distinction is between conceptual, logical, and physical abstraction levels. This has its roots in data modeling: conceptual elements represent the information the business finds relevant; logical elements provide logical structure to this information for manipulation by information systems; physical elements describe the storage of this information; for example, in the form of files or database tables. In the ArchiMate language, this corresponds with business objects, data objects, and artifacts, and the realization relationships between them.

      The distinction between logical and physical elements has also been carried over to the description of applications. The TOGAF Content Metamodel [4] describes logical and physical data, application, and technology components. Logical components are implementation or product-independent encapsulations of data or functionality, whereas physical components are tangible software components, devices, etc. The distinction within the TOGAF framework between Architecture Building Blocks (ABBs) and Solution Building Blocks (SBBs) is very similar. This distinction is again useful in progressing Enterprise Architectures from high-level, abstract descriptions to tangible, implementation-level designs. Note that building blocks may contain multiple elements, which are typically modeled using the grouping concept in the ArchiMate language.

      The ArchiMate language has three ways of modeling such abstractions. First, as described in [6], behavior elements such as application and technology functions can be used to model logical components, since they represent implementation-independent encapsulations of functionality. The corresponding physical components can then be modeled using active structure elements such as application components and nodes, assigned to the behavior elements. Second, the ArchiMate language supports the concept of realization. This can best be described by working with the Technology Layer upwards. The Technology Layer defines the physical artifacts and software that realize an application component. It also provides a mapping to other physical concepts such as devices, networks, etc. needed for the realization of an information system. The realization relationship is also used to model more abstract kinds of realization, such as that between a (more specific) requirement and a (more generic) principle, where fulfillment of the requirement implies adherence to the principle. Realization is also allowed between application components and between nodes. This way you can model a physical application or technology component realizing a logical application or technology component, respectively. Third, logical and physical application components can be defined as specializations of the application component element, as described in Chapter 15 (see also the examples in Section 15.2.2). The same holds for the logical and physical technology components of the TOGAF Content Metamodel, which can be defined as specializations of the node element (see Section 15.2.3).

      The ArchiMate language intentionally does not support a difference between types and instances. At the Enterprise Architecture abstraction level, it is more common to model types and/or exemplars rather than instances. Similarly, a business process in the ArchiMate language does not describe an individual instance (i.e., one execution of that process). In most cases, a business object is therefore used to model an object type (cf. a UML^® class), of which several instances may exist within the organization. For instance, each execution of an insurance application process may result in a specific instance of the insurance policy business object, but that is not modeled in the Enterprise Architecture.

3.7 Concepts and their Notation

      The ArchiMate language separates the language concepts (i.e., the constituents of the metamodel) from their notation. Different stakeholder groups may require different notations in order to understand an architecture model or view. In this respect, the ArchiMate language differs from languages such as UML or BPMN™, which have only one standardized notation. The viewpoint mechanism explained in Chapter 14 provides the means for defining such stakeholder-oriented visualizations.

      Although the notation of the ArchiMate concepts can (and should) be stakeholder-specific, the standard provides one common graphical notation which can be used by architects and others who develop ArchiMate models. This notation is targeted towards an audience used to existing technical modeling techniques such as Entity Relationship Diagrams