Quiz 3 - Key Terms
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Activation lifelines – Vertical rectangles on a sequence diagram that indicate when an object
is executing a method.
Artifact – A class invented by a system designer to handle a needed system function.
Benchmark – An evaluation of a system against some standard.
Boundary class – A class that exists on a system’s automation boundary, such as an input
window.
Business logic layer – The part of three-layer architecture that contains the programs that
implement the business rules of the application.
Composite state – A state containing other states and transitions (a path).
Concurrency, or concurrent state – The condition of being in more than one state at a time.
Centralized architecture – Architecture that locates all computing resources in a central
location.
Client – A process, module, object, or computer that requests services from one or more
servers.
Computer network – A set of transmission lines, equipment, and communication protocols
to permit sharing of information and resources.
Cohesion – A qualitative measure of the consistency of functions within a single class.
Control class – A class that mediates between boundary classes and entity classes, acting as
a switchboard between the view layer and domain layer.
Coupling – A qualitative measure of how closely the classes on a design class diagram are
linked.
Data access class – A class that is used to retrieve data from a database.
Data layer – The part of three-layer architecture that interacts with the database.
Destination state – For a particular transition, the state to which an object moves after the
completion of a transition.
Distributed architecture – Architecture that deploys computing resources in multiple
locations connected by a computer network.
Encapsulation – A design principle of objects in which both data and program logic are
included within a single self-contained unit.
Entity class – A design identifier for a problem domain class.
Instantiation – Creation of an object based on the template provided by the class definition.
Interaction diagram – Either a collaboration diagram or a sequence diagram that shows the
interactions between objects.
Lifeline, or object lifeline – The vertical line under an object on a sequence diagram to show
the passage of time for the object.
Message – The communication between objects within a use case.
Middleware – Computer software that implements communication protocols on the network
and helps different systems communicate.
Multi-computer architecture – A group of dissimilar computers that share processing load
through specialization of function.
Multi-tier architecture – Architecture that distributes application-related software or
processing load across multiple computer systems.
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Navigation visibility – A design principle in which one object is able to view and interact
with another object.
Network diagram – A model that shows how application layers are distributed across
locations and computer systems.
Object reuse – A design principle in which a set of standard objects can be used over and
over again within a system.
Origin state – For a particular transition, the original state of an object from which the
transition occurs.
Package – A symbol used to denote a group of similar elements.
Path – A sequential set of connected states and transitions.
Persistent class – An entity class that exists after a system is shut down.
Postcondition – A set of criteria that must be true upon completion of the execution of a use
case.
Precondition – A set of criteria that must be true prior to the initiation of a use case.
Scenario, or use case instance – A particular sequence of steps within a use case; a use case
may have several different scenarios.
Separation of responsibility – A design principle in which analysts divide a class into
several highly cohesive classes.
Server – A process, module, object, or computer that provides services over a network.
State – A condition during an object’s life when it satisfies some criterion, performs some
action, or waits for an event.
Stereotype – A way of categorizing a model element by its characteristics, indicated by
guillemets (<< >>).
System sequence diagram – A diagram showing the sequence of messages between an
external actor and the system during a use case or scenario.
Three-layer architecture – A client/server architecture that divides an application into the
view layer, business logic layer, and data layer.
Transition – The movement of an object from one state to another state.
Turnkey system – A complete system solution, including software and hardware, which can
be turned over to the purchasing organization.
Use case diagram – A diagram to show the various user roles and how those roles use the
system.
View layer – The part of three-layer architecture that contains the user interface.
Visibility – Notation of whether an attribute can be directly accessed by another object;
indicated by plus or minus signs.