UML diagram of soft skills

If you want to do well, you must first sharpen your tools. UML is a modeling tool that programmers need to use in the modeling process.

UML: Unified Modeling Language.The goal is to describe any kind of system in an object graph way.

UML can be divided into two categories: structural (describes a certain structure), behavioral (describes a certain behavior)

• Structural UML includes: class diagram, object diagram, component diagram, deployment diagram, package diagram.

• Behavioral UML includes: activity diagram, state machine diagram, sequence diagram, communication diagram, use case diagram, time diagram.

The various stages of software development

Requirements Analysis Phase:

• Use Case Diagram: Consists of actors, use cases, boundaries, and their relationships to form a view that describes the functionality of a system.

• Flowchart: Process-oriented, describing the process.

Outline Design Phase:

• Class Diagram: The static structure of the model, the relationship between classes.

• Object diagram: As a snapshot of the system at a certain moment, it is a static portrayal of the instances and their relationships of each class in the class diagram at a certain moment.Used to describe a set of objects at a time and the relationships between them.

Detailed Design Phase:

• Sequence Diagram: Describes the chronological sequence of messages sent between objects showing the dynamic collaboration between multiple objects.

• State Diagram: Describes the dynamic behavior of an entity in response to events.Focus on describing the results from the behavior.

• Activity diagram: illustrates the workflow of a business use case.Focus on describing from the results of behavior, object-oriented, focusing on the performance of system behavior.

• Sequence Diagram: Represents interactions as a two-dimensional diagram.

• Communication diagram: A diagram showing the interaction of objects.

Deployment Phase:

• Deployment diagram.

Several common pictures

Class Diagram

A class diagram is a diagram that describes a business concept.

There are six types of relationships between classes:

• Inheritance: A child class inherits from a parent class.

• Implementation: Implements classes and interfaces.

• Association: A class object is related to another class object.(Combination and aggregation also belong to association relationship)

• Dependency:A class method takes another class object as a parameter.(one-way)

• Composition: The relationship between the whole and the part between the classes, the whole and the part have a consistent life cycle.

• Aggregation: The whole-part relationship between classes, but member objects can exist independently of the whole object.

Relationships from strong to weak: inheritance->implementation->composition->aggregation->association->dependency.(The aggregation in DDD is consistent with the compositional relationship in UML)

Class diagram attribute representation:

+ public
- private
# protected
~ default
Abstract classes or abstract methods are in italics
Static classes or static methods are underlined
If the interface is on the classadd<<>>

UML diagram draws a class using the matrix representation of dividing lines:

• The top is the class name.

• The middle is the class attribute.

• The following are the class methods.

Complete class diagram example:

Deployment diagram

A deployment diagram is a diagram used to describe how a system is deployed and the relationships between systems.

I drew a picture in 2018 and shared it later.

Flowchart

Flowchart: Process-oriented, a diagram that describes a process.

Common basic symbols:

• Start/End: Indicates the beginning or end of a process.A flowchart has only one beginning and may have multiple ends.

• Process: A step in a process to be processed.

• Data: Indicates the input or output of data.

• Judgment: Used to indicate a decision in the process.

• Documentation: Represents written information pertaining to the process.

• Flow Direction: Arrows indicate the flow direction of a process.

The ForkjoinPool execution flow chart I drew before, the leftmost ForkJoinWorkerThread#run is actually started by the main method for subsequent execution. For the convenience of understanding, two starts are drawn.

Comparison of activity diagrams and flowcharts:

• Activity diagrams focus more on the behavioral relationship and sequence of activities between objects in a system.The flowchart can refer to the specific implementation steps of an algorithm, focusing on the processing process.

• Activity diagrams can be executed concurrently, while flow charts are executed sequentially and have a time sequence.

• Activity diagrams are object-oriented, and flowcharts are process-oriented.

Sequence diagram

Components:

1. Actor Actor: A system actor, which can be a human or other systems and subsystems.

2. Object Object: Object represents the role that the objects in the sequence diagram play in the interaction.

3. Lifeline: A lifeline represents the existence of an object in a sequence diagram over a period of time.

4. Control focus Activation: The period when an action is performed on behalf of an object in the sequence diagram.

5. Message Message: Defines classes for exchanging information in interaction and collaboration.