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This article will explain in detail the example analysis of the chain of responsibility programming mode in PHP. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

Overview

The mode of chain of responsibility is a kind of behavior mode of object. In the chain of responsibility pattern, many objects are connected by each object's reference to its subordinate to form a chain. The request is passed on the chain until an object on the chain decides to process the request. The client that made the request does not know which object on the chain will eventually process the request, which allows the system to dynamically reorganize and distribute responsibilities without affecting the client.

The definition of chain of responsibility pattern

Multiple objects have the opportunity to process the request, thus avoiding the coupling between the sender and receiver of the request, connecting the objects into a chain, and passing the request along the chain until an object processes it.

Advantages of the chain of responsibility model

The most obvious advantage is to separate the request from the processing. The requester does not need to know who handled the request, and the processor does not need to know the full picture of the request. The two are decoupled to improve the flexibility of the system.

The shortcomings of the chain of responsibility model

One is the performance problem, each request traverses from the beginning of the chain to the end of the chain, especially when the chain is long, performance is a problem. Second, debugging is not very convenient, especially when the chain is long and there are many links, due to the use of a similar recursive way, the logic may be more complex during debugging.

The roles involved in the chain of responsibility model are as follows:

Abstract processor (Handler) role: defines an interface for handling requests. If necessary, the interface can define a method to set and return a reference to the next home. This role is usually implemented by an abstract class or interface of php. The aggregation relationship of the Handler class in the figure above gives the reference of the concrete subclass to the following, and the abstract method handleRequest () standardizes the operation of the subclass to handle the request.

Specific handler (ConcreateHandle) role: after receiving the request, the specific processor can choose to process the request or pass the request to the next home. Since the specific handler holds a reference to the next home, if necessary, the specific handler can visit the next home

Let's take a look at an example of PHP's chain of responsibility pattern programming:

As you can see from the code, the client creates two handler objects and specifies that the next of the first handler object is the second handler object, while the second handler object has no next owner. The client then passes the request to the first handler object

This is the end of the article on "sample analysis of the programming mode of the chain of responsibility in PHP". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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