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This article mainly explains "the common application scenarios of the singleton pattern in php". The content of the explanation in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn the common application scenarios of the singleton pattern in php.

1. Windows's Task Manager (Task Manager) is a typical singleton mode (this is familiar). Think about it, isn't it? can you open two windows task manager? If you don't believe me, try it yourself.

2. Windows's Recycle Bin (Recycle Bin) is also a typical singleton application. The Recycle Bin maintains the only instance throughout the operation of the system.

3. The counter of the website is generally implemented in singleton mode, otherwise it is difficult to synchronize.

4. The log application of an application is generally implemented in singleton mode, which is generally due to the fact that the shared log file has been open all the time, because there is only one instance to operate, otherwise the content is difficult to append.

5. The singleton mode is also used to read the configuration objects of Web applications, because the configuration files are shared resources.

6. Database connection pool is generally designed in singleton mode, because database connection is a kind of database resource. The use of database connection pool in database software system is mainly to save the efficiency loss caused by opening or closing database connection, which is still very expensive, because why use singleton mode to maintain it. This loss can be greatly reduced.

7. Multi-threaded thread pools are generally designed in singleton mode, because the thread pool is convenient to control the threads in the pool.

8. The file system of the operating system is also a concrete example of the implementation of a large singleton pattern, where an operating system can have only one file system.

9. HttpApplication is also a typical application of unit examples. Anyone familiar with the entire request life cycle of http://ASP.Net(IIS) should know that HttpApplication is also a singleton pattern, and all HttpModule share a HttpApplication instance.

To sum up the above, it is not difficult to see:

Scenarios where singleton mode is applied are generally found under the following conditions:

(1) in the case of resource sharing, avoid the performance or loss caused by the operation of resources. Apply the configuration as shown in the log file above.

(2) in the case of controlling resources, it is convenient for resources to communicate with each other. Such as thread pool and so on.

Thank you for your reading. The above is the content of "the common application scenarios of the singleton pattern in php". After the study of this article, I believe you have a deeper understanding of the common application scenarios of the singleton pattern in php, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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