AGGREGATEA cluster of associated objects that are treated as a unit for the purpose of data changes. External references are restricted to one member of the aggregate, designated as the root. A set of consistency rules applies within the aggregate's boundaries. |
ANALYSIS PATTERNA group of concepts that represents a common construction in business modeling. It may be relevant only to one domain or may span many domains. |
ASSERTIONA statement of the correct state of a program at some point, independent of how it does it. Typically, an assertion specifies the result of an operation of an invariant of a design element. |
BOUNDED CONTEXTThe delimited applicability of a particular model. Bounding Contexts gives team members a clear and shared understanding of what has to be consistent and what can develop independently. |
CLIENTA program element that is calling the element under design, using its capabilities. |
COHESIONLogical agreement and dependence |
COMMAND(a.k.a. modifier) An operation that effects some change to the system (for example, setting a variable). An operation that intentionally creates a side effect. |
CONCEPTUAL CONTOURAn underlying consistency of the domain itself, which, if reflected in a model, can help the design accommodate change more naturally. |
CONTEXTThe setting in which a word or statement appears that determines its meaning. See Bounded Context. |
CONTEXT MAPA representation of the Bounded Contexts involved in a project and the actual relationships between them and their models. |
CORE DOMAINThe distinctive part of the model, central to the user's goals, that differentiates the application and makes it valuable. |
DECLARATIVE DESIGNA form of programming in which a precise description of properties actually controls the software. An executable specification. |
DEEP MODELAn incisive expression of the primary concerns of the domain experts and their most relevant knowledge. A deep model sloughs off superficial aspects of the domain and naive interpretations. |
DESIGN PATTERNA description of communicating objects and classes that are customized to solve a general design problem in a particular context. |
DISTILLATIONA process of separating the components of a mixture to extract the essence in a form that makes it more valuable and useful. In software design, the abstraction of key aspects in a model, or the partitioning of a larger system to bring the Core Domain to the fore. |
| | DOMAINA sphere of knowledge, influence or activity. |
DOMAIN EXPERTA member of a software project whose field is the domain of the application, rather than software development. Not just any user of the software, the domain expert has deep knowledge of the subject. |
DOMAIN LAYAERThat portion of the design and implementation responsible for domain logic within a Layered Architecture. The domain layer is where the software expression of the domain model lives. |
ENTITYAn object fundamentally defined not by its attributes, but by a thread of continuity and identity. |
FACTORYA mechanism for encapsulating complex creation logic and abstracting the type of a created object for the sake of a client. |
FUNCTIONAn operation that computes and returns a result without observable side effects. |
IMMUTABLEThe property of never changing observable state after creation. |
IMPLICIT CONCEPTA concept that is necessary to understand the meaning of a model or design but is never mentioned. |
INTENTION-REVEALING INTERFACEA design in which the names of classes, methods and other elements convey both the original developer's purpose in creating them and their value to a client developer. |
INVARIANTAn Assertion about some design element that must be true at all times, except during specifically transient situations such as the middle of the execution of a method, or the middle of an uncommitted database transaction. |
ITERATIONA process in which a program is repeatedly improved in small steps. Also, one of those steps. |
LARGE-SCALE STRUCTUREA set of high-level concepts, rules or both that establishes a pattern of design for an entire system. A language that allows the system to be discussed and understood in broad strokes. |
LAYERED ARCHITECTUREA technique for separating the concerns of a software system, isolating a domain layer, among other things. |
LIFE CYCLEA sequence of states an object can take on between creation and deletion, typically with constraints to ensure integrity when changing from one state to another. May include migration of an Entity between systems and different Bounded Contexts. |
MODELA system of abstractions that describes selected aspects of a domain and can be used to solve problems related to that domain. |
| | MODEL-DRIVEN DESIGNA design in which some subset of software elements corresponds closely to elements of a model. Also, a process of co-developing a model and an implementation that stay aligned with each other. |
MODELING PARADIGMA particular style of carving out concepts in a domain, combined with tools to create software analogs of those concepts (for example, object-oriented programming and logic programming). |
RERPOSITORYA mechanism for encapsulating storage, retrieval and search behavior which emulates a collection of objects. |
RESPONSIBILITYAn obligation to perform a task or know information. |
SERVICEAn operation offered as an interface that stands alone in the model, with no encapsulated state. |
SIDE EFFECTAny observable change of state resulting from an operation, whether intentional or not, even a deliberate update. |
SIDE-EFFECT-FREE FUNCTIONS
STANDALONE CLASSA class that can be understood and tested without reference to any others, except system primitives and basic libraries. |
STATELESSThe property of a design element that allows a client to use any of its operations without regard to the element's history. A stateless element may use information that is accessible globally and may even change that global information (that is, it may have side effects) but holds no private state that affects its behavior. |
STRATEGIC DESIGNModeling and design decisions that apply to large parts of the system. Such decisions affect the entire project and have to be decided at team level. |
SUPPLE DESIGNA design that puts the power inherent in a deep model into the hands of a client developer to make clear, flexible expressions that give expected results robustly. Equally important, it leverages that same deep model to make the design itself easy for the implementer to mold and reshape to accommodate new insight. |
UBIQUITOUS LANGUAGEA language structured around the domain model and used by all team members to connect all the activities of the team with the software. |
UNIFICATIONThe internal consistency of a model such that each term is unambiguous and no rules contradict. |
VALUE OBJECTAn object that describes some characteristic or attribute but carries no concept of identity. |
WHOLE VALUEAn object that models a single, complete concept. |
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