Learn about the functional interface

Originally, the notion of interface comes from the physics. In its current meaning, it is inseparable the computing and is closely linked to that of the interactivity.
In the IT practice, interfaces allow different computers to communicate between them. It is the base of the Internet protocols.
Some programming languages have various methodologies to allow the realization of interfaces. Generally, any programming language can implement an interface, but the following programming languages offer specific opportunities of interfacing one way or another: language C, Delphi, Eiffel, Java, PHP, Python …

Learn about the functional interface

A functional interface (functional interface) is basically an interface in which a single abstract method is defined. It must meet certain requirements:
• it must have a single abstract method declared
• the methods defined in the Object class are not considered as abstract methods
• all methods must be public
• it can have default methods and static

A functional interface defines only one abstract method.

To be a functional interface, an interface must have a single abstract method declared. It can have either no, or more redefinitions of methods of the Object class or default methods.
A functional interface can not be more than an abstract method. If more abstract methods defined in the interface, one that will not be a functional interface.
Each functional interface has only one abstract method called functional approach (functional method) for which the parameters and return value must match or be adapted.
A functional interface defines a method that can be used to switch parameter:
- A reference to an instance method
- A reference to a static method
- A reference to a builder
- A lambda expression
- An anonymous inner class

With interfaces, our advanced php application development can get a code much clearer and easier to maintain. The programs that have interfaces are more easily adaptable.

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