The decorator pattern

The decorator pattern

When we inherit a class we can get the part of its methods and properties, the decorator pattern to a certain extent as a solution alternative succession. It can extend the dynamic object and function transparency.

specification

Decorator mode requires the following three requirements.

1. decorator to be associated with a decorator.

2. decorator decorators to achieve the same interface.

3. For not require an enhanced method, the method can be invoked directly decorator.

for example

Definition of standardized interfaces

public interface animal {
    
    public abstract void eat();
    
    public abstract void exercise();
}

Implement the decorator interface

public class dog implements animal {

    @Override
    public void eat() {
        System.out.println("啃骨头");
    }

    @Override
    public void exercise() {
        System.out.println("跑");
    }

}

Association is to implement the interface and decorators decorators

the implements to Huskie class public Animal { 
    // Get the object is a decorator's 
    Private Dog D; 

    @Override 
    public void EAT () { 
        d.eat (); 
    } 

    @Override 
    public void Exercise () {  d.exercise ();  the System. Out.println ( "pushers" );  } 
     }

Feature

The decorator pattern relative to inherit in terms of more flexibility while achieving a variety of combinations.