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Singleton mode Demand proposals: In architecture design, some classes can only have one Single Instance in the whole system life cycle. Such as: supermarket cash register system, a monitor, a scanning gun, a keyboard.. Question:How to define a class so that it can only create one object at most? To control the number of objects in a class, t ...

PostgreSQL comes with a simple full-text retrieval engine that enables full-text retrieval of small amounts of data.In this article, we will guide you through this feature, which is sufficient for small-volume searches without the need to build additional heavy-weight full-text retrieval servers such as ES. For detailed full-text ...

Usually, in the context of front-end and back-end separation, our back-end services are usually returned to the front-end formatted data, such as Json. At the beginning, we used JSON package to produce a JSON string, which is customized with some API s of http protocol. spring has evolved to the present day and has packaged generic ...

"Demeter's Law": This means that "the less your class knows about other classes, the better"; 1. Concept: A software entity should interact with other entities as little as possible. Each software unit has the least knowledge of other units, and is limited to those software units closely related to the uni ...

In the last article, we introduced Python's functions and modules, and now we introduce exceptions and files in Python. To view the previous article, please click: https://www.cnblogs.com/dustman/p/9963920.html Exceptions and documents abnormal Exceptions are also called exceptions. You've seen exceptions in previous articles. When program runn ...

Summary: Understand prototype. Original: An in-depth guide to JavaScript prototypes Author: Front end wit Fundebug Copyright shall be owned by the original author when authorized to reproduce. You can't go far in JavaScript without learning how to handle objects.They are the basis for almost every aspect of the JavaScript programming langua ...

1. What is an integrator? We can create lists directly by using the Formula of Lists. However, due to memory constraints, the list capacity must be limited. Moreover, creating a list of 1 million elements not only takes up a lot of storage space, but if we only need to access the previous one, then most of the elements are wasted. So, if the l ...

What is zero copy?Let's start with a look at traditional I/O operations.Let's say that the user process now copies one file to another.Then the user program must first read this file into memory, and then write the data in memory to another file.However, file read-in memory is not directly read into the memory of user processes, but read into t ...

In this introductory tutorial, we will build an application development environment in Taifang and learn to write a voting intelligence contract. In this tutorial, let's build a simple "Hello World!" application, which is a voting application. The application is simple, all it does is initialize a set of candidates, get anyone to vot ...

Since most SIP registry server writings on the web are C/C++/python, post this post and share the JAVA implementation GB28181 defines the SIP-based video monitoring interconnection specification. For most private protocol-implemented monitoring systems, if they want to access the SIP architecture, they need to use the gateway. GB28181 specifie ...