Basic concepts of UML (handover)

Basic concepts of UML

UML Overview

　　Introduction to UML

UML provides a unified, standard, and visual modeling language for Object-Oriented software design. It is applicable to the whole process of describing case-driven, architecture-centered software design.

The definition of UML consists of UML Semantics and UML notation.

(1) UML Semantics: the semantic description of UML enables developers to get a consistent semantic understanding and eliminate the impact of different representation methods.

(2) UML notation: UML notation defines the notation of UML symbols, which provides a standard for System Modeling by developers or development tools using these graphical symbols and text syntax.

Composition of UML model diagrams

Things: the most basic component in a UML model. It is an abstract of representative components.

Relationship: links closely link things.

Diagrams.

UML transactions

UML contains four types of things: component things, behavior things, group things, and comment things.

Component thing: static part of the UML model, which describes concepts or physical elements.

It includes the following types:

Class: description of an object with the same attributes, the same operation, the same link, and the same Semantics

Interface: describes the external visible behavior of an element, that is, the definition of a service set.

Collaboration: a set of interactions between a group of things.

Use Case: represents a part of a system or system's behavior, and is a set of action sequences.

Component: A physical component in the system that can be replaced

Node: A physical element that exists during running.

In addition, participants, signal applications, document libraries, and page tables are all variants of the above basic things.

Behavior thing: the dynamic part of the UML Model diagram. It describes the behavior that spans space and time.

Interaction: a set of messages between a group of component things that implement a function, involving messages, action sequences, links

State Machine: describes the sequence of states that a thing or interaction experiences in responding to an event within the lifecycle.

Group transaction: the organizational part of the UML Model diagram, which describes the organizational structure of the transaction.

Package: Group Elements

Annotation: The description of the UML Model diagram. It is used to describe and explain the elements in the model.

Annotation: A simple symbol that restricts or interprets elements.

UML relationship

Dependecy: a semantic relationship between two things. A change in one thing (independent thing) affects the semantics of another thing (dependent thing.

Association: a structural relationship that specifies the relationship between the object of a transaction and the object of another transaction.

Generalization: A special/general relationship. It can also be seen as an inherited relationship.

Implementation: a semantic relationship between class elements. One Class element specifies the contract that is executed by another class element.

 UML diagrams and features

Use case diagram: It describes system functions from the user's perspective and is a model diagram of system functions observed by the user. Use Cases are a functional unit in the system.

Class digraphs: Describes the static structure of classes in the system. It defines not only the classes in the system, but also the relationships between classes, such as association, dependency, and aggregation. It also includes the internal structure of the class (attributes and operations of the class ). A class chart is organized around a class. Other elements in the class chart belong to a class or are associated with the class.

Object digraphs: it is an instance of a class graph and is almost identical to a class graph. Their difference is that the object graph shows multiple object instances of the class, rather than the actual class.

Sequence diagram: displays the dynamic cooperative relationship between objects. It emphasizes the order in which messages are sent between objects and displays interactions between objects. A Sequence Chart is used to represent the behavior sequence in the use case. When executing a use case behavior, each message in the sequence diagram corresponds to a class operation or trigger event that causes status conversion.

Colcollaboration diagram: Describes the collaboration relationships between objects. A collaboration diagram is similar to a sequence diagram and shows the dynamic cooperation relationships between objects. In addition to information exchange, a collaboration chart also displays objects and their relationships. Its purpose is to represent the implementation of a class operation.

State chart divisor: it is a model diagram of all the processes that a class object may experience. A status chart consists of the status of an object and the transition of these statuses.

Activity digraphs: a variant of a state chart used to describe the activities involved in the workflow that executes an algorithm. Describes a set of ordered or concurrent activities.

Component diagram (Component divisor): Creates a model for the system component. A component is the software unit used to construct an application. It also includes the dependency between components, this allows you to estimate the impact of modifications to system components on the system.

Deployment diagram: Describes the arrangement of running component instances on a node instance. A group of running resources on a node, such as computers, devices, or storage. This view allows evaluation of allocation results and resource allocation.

Relationship between various UML diagrams 

UML syntax description

Link: http://www.cnblogs.com/LT0314/p/4059461.html

Basic concepts of UML (handover)