An event that is generated when one or more attributes or associations change value according to an expression.
Context
The element specified in one of the UML diagrams for which the OCL expression is defined.
Context definition
The text or symbol that defines the relationship between an OCL expression and the element in the part of the model that is specified by UML diagrams.
Contextual instance
An instance of the contextual type of an OCL expression.
Contextual type
The type of the object for which an OCL expression will be evaluated.
Contract
A description of the services that are provided by an object using pre- and postconditions.
Derivation rule
A rule that specifies the value of a derived element.
Derived class
A class whose features can be derived completely from already existing (base) classes and other derived classes.
Design by contract
A way of specifying software by describing the contract of each component or class explicitly, using pre- and postconditions.
Diagram
A visible rendering of (a part of) a model.
Dynamic multiplicity
The multiplicity of an association is dynamic, when it is determined based on another value in the system.
Features
The attributes, operations, and associations that are defined for a type.
Guard
A condition on a transition in a statechart.
Invariant
An invariant is a boolean expression attached to a type that states a condition that must always be met by all instances of the type for which it is defined.
Iterator variable
A variable that is used within the body of a loop expression to indicate the element of the collection for which the body is being calculated.
Language
A clearly defined way to model ( parts of) a system. A definition of a language always consists of a syntax definition and a semantics definition.
Metamodel
A description or definition of a well-defined language. Equivalent to metalanguage .
Model
A consistent, coherent set of model elements with features and restrictions.
Model Driven Architecture
A framework for software development in which the process is driven by the automated transformation of platform-independent models into platform-specific models.
Model-driven software development
The process of developing software using different models on different levels of abstraction with (automated) transformations between these models.
Model repository
The storage of all model elements in an automated tool.
Navigation
Accessing objects different from the contextual instance using associations. Also, the association end through which a contextual instance may access another object.
Object type
A type that has reference-based identity.
Optional multiplicity
The multiplicity of an association is optional when its lowest bound is zero.
Platform
A set of software pieces implemented with a specific technology on specific hardware, and/or specific hardware pieces that constitute the execution environment of a system.
Platform-independent model
A model containing no details that have meaning only within a specific platform.
Platform-specific model
A model containing details which have meaning only within a specific platform.
Postcondition
An expression attached to an operation that must be true at the moment when the operation has just ended its execution.
Precondition
An expression attached to an operation that must be true at the moment when the operation is going to be executed.
Protocol interpretation of statecharts
A manner to understand statecharts in which every event, action, and activity is mapped to an operation of the class for which the statechart is defined.
See also [Real-time interpretation of statecharts]
Query operation
An operation that has no side effects.
Real-time interpretation of statecharts
A manner to understand statecharts in which one single process executes the transitions by taking an event from an input queue and disposing it as specified by the statechart.
Reference-based identity
A type has reference-based identity when two references are considered to be unequal when the instances they refer to are not the same, even when all values held by both instances are the same.
Semantics
A definition of the meaning of models that are well- formed according to a syntax of a specific language.
Standard type
A type predefined in the OCL language, i.e., a type that is not defined by the user and cannot be altered by the user.
Syntax
A set of rules that defines which models are well-formed in a specific language.
System
A part of the world that is the subject of reasoning.
Transformation
A transformation is the generation of a model based on another model and a set of transformation rules, while preserving the meaning of the source model in the target model insofar as this meaning can be expressed in both models.
Type
A term used in this book to indicate either a class, a datatype, an interface, or a component.
Type conformance
Indicates whether an instance of one type can be substituted for an instance of another type. If so, the first type confoms to the second type.
UML profile
A language definition (a metamodel) based on the UML metamodel, with extra rules and a mapping of the language concepts to the UML syntax.
User-defined type
A model element defined in a UML diagram that represents an instance or set of instances ”usually a class, datatype, component, or interface.
Value-based identity
A type has value-based identity when two references are considered to be equal when all values held by the instances they refer to are the same.
