Introduction to the three elements of UML Class Diagram

This article mainly introduces the "introduction of the three major UML class diagram elements". In the daily operation, I believe many people have doubts about the introduction of the three major UML class diagram elements. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about the "introduction of the three major UML class diagram elements". Next, please follow the editor to study!

Fully understand the elements of UML class diagram

When developing Java applications, developers who want to make effective use of Unified Modeling language (UML) must have a comprehensive understanding of UML elements and how they map to Java. This article focuses on the elements in the UML class diagram.

Class diagram is the most commonly used UML diagram, which is used to describe the structured design of the system. This includes class relationships and the properties and behaviors associated with each class. Class diagrams are an excellent representation of inheritance and composition relationships. In order to use the class diagram as an efficient communication tool, developers must understand how to convert the elements that appear on the class diagram into Java. Let's further explore this conversion process.

element

In the following sections, we explain the elements of the UML class diagram and their corresponding representations in Java. I will list the element name, followed by a short code snippet and a diagram to show what the element looks like on the class diagram. This element is briefly summarized in the * * of each section.

Class (Class)

The class (figure A) in the UML class diagram element is the blueprint for the object and contains three components. * are the class names defined in Java. The second is the attributes. The third is the method provided by this class.

Properties and actions can be preceded by a visibility modifier. The plus sign (+) indicates public visibility. The minus sign (-) indicates private visibility. The # sign indicates protected visibility. Omitting these modifiers indicates visibility at the package (package) level. If the property or operation is underlined, it is static. In the operation, you can also list the parameters it accepts, as well as the return type, as shown in the "Java" area of figure A.

Figure A

Package (Package)

The package (figure B) in the UML class diagram element is a general-purpose composition mechanism. A package in UML corresponds directly to a package in Java. In Java, a package may contain other packages, classes, or both. When modeling, you usually have a logical package, which is mainly used to organize your model. You will also have physical packages that are converted directly into Java packages in the system. The name of each package uniquely identifies the package.

Figure B

Interface (Interface)

The interface (figure C) in the UML class diagram element is a collection of operations that specify the services provided by a class. It corresponds directly to an interface type in Java. The interface can be represented either by the icon in figure C or by an attached standard class. In general, you can know the relationship with other classes according to what the interface looks like on the class diagram.

Figure C

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