Shulou(Shulou.com)06/03 Report--

Today, I will talk to you about the meaning of the singleton model, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

Singleton pattern is a common software design pattern of creation type. the class created by the method of this pattern has only one instance in the current process, and its benefit ensures that all objects access the unique instance. and reduce memory overhead and system performance overhead.

Singleton pattern is one of the simplest forms of design patterns. The purpose of this pattern is to make an object of the class the only instance in the system. To achieve this, you can start by instantiating it by the client. Therefore, you need to use a mechanism that allows only unique instances of the object class to be generated to "block" access to all objects that you want to generate. Use the factory method to restrict the instantiation process. This method should be static (class method), because it makes no sense for an instance of the class to generate another unique instance.

Implementation of singleton pattern

There are usually two ways to build the singleton pattern in the Java language:

Lazy-Thread unsafe: the most basic implementation, thread context singleton, does not need to be shared with all threads and does not require locks such as synchronize to improve performance.

Lazy-thread safe: coupled with lazy mode based on thread safety such as synchronize, the performance is relatively low and synchronization is not needed most of the time.

The hungry way. A global singleton instance is built when the class is loaded.

Double check lock. Based on lazy style, synchronize keyword and volatile keyword are used to ensure that there is no competition between threads during the first creation, resulting in multiple instances. Only when the first creation is synchronized, the performance is relatively high.

Registration. Exists as a global property of the creation class, created when the creation class is loaded

Enumerate. Enumerated classes in java are themselves a singleton pattern.

After reading the above, do you have any further understanding of what the singleton pattern means? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.