Essential Books

Traits to keep classes clean

suggest change

Over time, our classes may implement more and more interfaces. When these interfaces have many methods, the total number of methods in our class will become very large.

For example, let’s suppose that we have two interfaces and a class implementing them: 

interface Printable {
    public function print();   
    //other interface methods...
}

interface Cacheable {
    //interface methods
}

class Article implements Cachable, Printable {  
    //here we must implement all the interface methods
    public function print(){ {
        /* code to print the article */ 
    }
}

Instead of implementing all the interface methods inside the Article class, we could use separate Traits to implement these interfaces, keeping the class smaller and separating the code of the interface implementation from the class.

From example, to implement the Printable interface we could create this trait: 

trait PrintableArticle {
    //implements here the interface methods
    public function print() {
        /* code to print the article */ 
    }
}

and make the class use the trait: 

class Article implements Cachable, Printable {
    use PrintableArticle;
    use CacheableArticle; 
}

The primary benefits would be that our interface-implementation methods will be separated from the rest of the class, and stored in a trait who has the sole responsibility to implement the interface for that particular type of object.

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Traits:
* Traits
* What is a Trait
* Traits to facilitate horizontal code reuse
* Conflict Resolution
* Implementing a Singleton using Traits
* Multiple Traits Usage
* Changing Method Visibility
* Traits to keep classes clean
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