[JAVA] Builder Pattern

A pattern in which the user unknowingly performs a complex program combination (composition)
A constructor that requires multiple constructors or has many combinations of arguments is programmed. Can also be used when externalizing </ font>

This page describes the Builder Pattern.

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Check with the following class structure

class	Explanation
abstract Builder.class	Define multiple methods
samBuilder1.class	Builder.Implement class
samBuilder2.class	the same
Director.class	Compose multiple methods of Builder
user(Main.class)	Check the operation

User Includes the meaning that other developers use this pattern

`Builder.class`


abstract class Builder{
  abstract void line1();
  abstract void line2();
  abstract void msg(String msg);
}

`samBuilder1.class`


class samBuilder1 extends Builder{
  void line1(){System.out.println("|||||||||||||");}
  void line2(){System.out.println(".............");}
  void msg(String msg){System.out.println(msg);}
}

`samBuilder2.class`


class samBuilder2 extends Builder{
  void line1(){System.out.println("=============");}
  void line2(){System.out.println("~~~~~~~~~~~~~");}
  void msg(String msg){System.out.println(msg);}
}

`Director.class`


class Director{
  Builder builder;
  Director (Builder builder){this.builder=builder;}

  void construct(String msg){  //Write complex constructors here or combine methods
    builder.line1();           // A
    builder.msg(msg);          // B
    builder.line2();           // C
  }                            // A~The output changes by changing the order of C. Example of building a method
}

`user(Main.class)`


public static void main(String[] args){
  samBuilder1 sam1 = new samBuilder1();
  Director dc1 = new Director(sam1);
  dc1.construct("Builder");

  samBuilder2 sam2 = new samBuilder2();
  Director dc2 = new Director(sam2);
  dc2.construct("builder");
}}

The user cannot see the concrete method of Builder