Programmer Think

Application scenarioDecorator pattern mainly solves the problem of too complex inheritance relationship, and replaces inheritance through composition. Its main function is to add enhancements to the original class.One feature of decorator pattern is that multiple decorators can be nested on the original class. In order to meet this application ...

preface Today, in the process of interviewing others, I asked about the design mode. He said command mode, what!! I haven't heard of it. I can only pretend to be calm, ask him, and quickly turn over the book when I come back. Command mode Daily endorsement: Command Pattern is a data-driven design pattern, which belongs to behavioral ...

On observer model Observer mode definition It refers to the one to many dependency between multiple objects. When the state of an object changes, all objects that depend on it are notified and automatically updated. This mode is sometimes called publish subscribe mode, which is an object behavior mode. Take a common example There is an exampl ...

Responsibility chain model Other modes The responsibility chain pattern is a behavior design pattern that allows you to send requests along the handler chain. After receiving the request, each handler can process the request or pass it to the next handler in the chain. In the responsibility chain pattern, each recipient usually contains a re ...

In some systems, in order to save memory resources and ensure the consistency of data content, only one instance can be created for some classes, which is the so-called singleton mode. 1, Definition and characteristics of singleton mode Definition of Singleton pattern: a pattern in which a class has only one instance and the class can create ...

1. Class adapter mode When I first came here in the morning and saw my brother drinking water, I suddenly didn't feel very good. I said: the weather is a little gloomy today. It's estimated to rain again. It's wet everywhere. Even the design mode I just learned feels like water injection! My brother glanced at me and said: what do you say? ...

Design pattern with Python 4: factory pattern Factory pattern essentially includes two different design patterns: factory method and abstract factory. But they essentially encapsulate the created objects, so as to realize the decoupling design pattern to some extent, so they are introduced together. Different from the Head First design patter ...

Android Studio download and environment construction link: Introduction to Android Studio: overview of Android system architecture and construction of development environment Create and run the first HelloWorld program 1, Create Android project 1. Open Android Studio and create a new project 2. Configure new project 3. Set application Run ...

Cases in life Different countries use different plugs. One day, Lao Wang, a programmer, went to Thailand for a trip and was about to charge his mobile phone when he came back to the hotel at night. He found that the charger could not fit the socket in Thailand. At this time, Lao Wang was very depressed, so he called the management personnel of ...

Design principles of java program 6 principles: Single responsibility: a class and method do only one thing. Open / close: close the modification and expand the development. Richter substitution: subclasses can extend new methods, but cannot modify the existing methods of the parent class (the parent class has provided specific implementation ...