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Design Patterns in Java (Creational) - Builder Pattern

Builder Pattern

  • Handle complex constructors
  • Large number of parameters
  • Immutability

  • Ex
  • LaunchBuilder is the static inner class
  • Each method from LaunchBuilder is the equivalent to the setters
  • In this way the result class "LauchOrder" cannot be modified, only have getters


public class LaunchOrder {

    
    public static class LaunchBuilder {

        private String bread;
        private String meat;
        private String dressing;
        private String condiments;

        public LaunchBuilder(){
        
        }
        
        public LaunchOrder build(){
            return new LaunchOrder(this);
        }
        
        public LaunchBuilder bread(String bread){
            this.bread = bread;
            return this;
        }

        public LaunchBuilder meat(String meat){
            this.meat = meat;
            return this;
        }

        public LaunchBuilder dressing(String dressing){
            this.dressing = dressing;
            return this;
        }

        public LaunchBuilder condiments(String condiments){
            this.condiments = condiments;
            return this;
        }

        
    }
    
   
    private final String bread;
    private final String meat;
    private final String dressing;
    private final String condiments;

     public LaunchOrder(LaunchBuilder lb){
         this.bread = lb.bread;
         this.meat = lb.meat;
         this.dressing = lb.dressing;
         this.condiments = lb.condiments;
     }

     
    public String getBread() {
        return bread;
    }

    public String getMeat() {
        return meat;
    }

    public String getDressing() {
        return dressing;
    }

    public String getCondiments() {
        return condiments;
    }
}


------------------ Main ----------------
public static void main(String[] args) {
        LaunchOrder.LaunchBuilder lb = new LaunchOrder.LaunchBuilder();
        
        lb.bread("pan de ajo").condiments("cebolla").meat("jamon");
        
        LaunchOrder lo = lb.build();
        
        System.out.println(lo.getBread());
    }





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