The role of the final keyword in php

The final keyword plays the following roles in PHP: class declaration: prevents classes from being inherited; method declaration: prevents methods from being overridden; functions include: enhancing security, improving performance, enforcing design principles, and avoiding unnecessary inherit.

The role of the final keyword in php

The final keyword has the following functions in PHP:

1. Class declaration

Add the final keyword before the class declaration to indicate that the class cannot be inherited. This means:

• Subclasses inheriting this class will be prohibited.
• All methods in a final class must be final methods (see below).

2. Method declaration

Add the final keyword before the method declaration to indicate that the method cannot be overridden. This means:

• Subclasses that inherit this method will not be able to redefine it.
• Final methods can only appear in final classes.

Function:

• Enhanced security: Final classes and methods can prevent unauthorized modification or extension.
• Improve performance: The PHP interpreter can optimize final classes and methods because they will not be overridden.
• Enforce design principles: Using the final keyword can ensure that design principles, such as class closure, are followed.
• Avoid unnecessary inheritance: The final class prevents unnecessary inheritance, thereby simplifying the code structure.

Note:

• The final class and its methods can be reused, but cannot be modified.
• The final keyword can only be used for classes and methods, not other elements (such as properties or constants).

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