Programmer Think

4. Builder Pattern catalogue Builder pattern Model motivationPattern definitionPattern structureSequence diagramcode analysispattern analysisexampleadvantageshortcomingApplicable environmentMode applicationMode extensionsummary 4.1. Model motivation There are many components in the real world, such as the wheel, the steering wheel and ...

Project address: https://gitee.com/caochenlei/design-pattern Chapter 1 Introduction to command mode Introduction to command mode: In software development system, there is often a close coupling relationship between "method requester" and "method implementer", which is not conducive to the expansion and maintena ...

Several commonly used design patterns (I): design principle, strategy pattern and observer pattern Core: reuse - resist change Object oriented design principles: 1. Dependency Inversion Principle (DIP) High level modules (stable) should not rely on low-level modules (change), but both should rely on abstraction (stable). Abstract (st ...

The design principle is a summary of some experience guiding our code design, that is, "mental method"; Object oriented is our "weapon"; Design pattern is "move". Based on mental skill, use weapon moves to deal with complex programming problems. Me: sister, what do I think you've been busy lately? Didn't you chang ...

1) You can obtain different phone numbers from another Activity to call. 2) You can turn on the camera to take pictures and display them in the picture box 3) You can send text messages 4) The interface is shown in the figure 1, Page layout Upper code <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http: ...

1, Definition Adapter Pattern: one of the structural patterns, which converts the interface of a class into another interface desired by the customer. The Adapter Pattern allows classes that cannot work together because of incompatible interfaces to work together. 2, UML class diagram 3, Roles and responsibilities Target role: this role defin ...

The observer pattern defines a one to many dependency that allows multiple observer objects to listen to a subject object at the same time. When the state of the subject object changes, it will notify all observer objects so that they can update themselves automatically. -- Dahua design mode How would you write the code if you had to inform ...

catalogue 18. Responsibility chain model 18.1 example 2 19. Observer mode 19.1 example 2 20. Status mode 18. Responsibility chain model Responsibility chain mode: make multiple objects have the opportunity to process the request, so as to avoid the coupling relationship between the sender and receiver of the request. Connect these objec ...

The content comes from javascript Design Patterns and development practice 1, Singleton mode Definition: ensure that a class has only one instance and provide a global access point to access it. For example, when we click the login button, a login floating window will appear in the page, and this login floating window is unique. No matter how ...

The bridge pattern is simply to separate the abstract part from its implementation part, so that they can change independently. In some compositions, if each class implements different services, Cartesian product may appear, and the use of bridge mode can easily decouple abstraction from implementation, so that they can change independently. H ...