[Anonymous Classes] 람다가 있기전 익명클래스가 있었다.

학습목표 :Anonymous Classes 를 정의할 수 있다.

 

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https://docs.oracle.com/javase/tutorial/java/javaOO/anonymousclasses.html

Anonymous Classes (The Java™ Tutorials > Learning the Java Language > Classes and Objects)

Anonymous classes enable you to make your code more concise. They enable you to declare and instantiate a class at the same time. They are like local classes except that they do not have a name. Use them if you need to use a local class only once.

 

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Anonymous Classes Sample

package team.study._anonymous_classes;

public class HelloWorldAnonymousClasses {
	  
    interface HelloWorld {
        public void greet();
        public void greetSomeone(String someone);
    }
  
    public void sayHello() {
        
    	/* 전통적인 인터페이스 구현체 */
        class EnglishGreeting implements HelloWorld {
            String name = "world";
            public void greet() {
                greetSomeone("world");
            }
            public void greetSomeone(String someone) {
                name = someone;
                System.out.println("Hello " + name);
            }
        }
      
        HelloWorld englishGreeting = new EnglishGreeting();
        
        /* 익명 클래스 사용 */     
        HelloWorld frenchGreeting = new HelloWorld() {
         
            String name = "tout le monde";
            public void greet() {
                greetSomeone("tout le monde");
            }
            public void greetSomeone(String someone) {
                name = someone;
                System.out.println("Salut " + name);
            }
        };
        
        /* 익명 클래스 사용 */
        HelloWorld spanishGreeting = new HelloWorld() {
            String name = "mundo";
            public void greet() {
                greetSomeone("mundo");
            }
            public void greetSomeone(String someone) {
                name = someone;
                System.out.println("Hola, " + name);
            }
        };
        
        /* 인터페이스 구현체 실행 */
        englishGreeting.greet();
        
        /* 익명클래스 실행 */
        frenchGreeting.greetSomeone("Fred");
        
        /* 익명클래스 실행  */
        spanishGreeting.greet();
    }

    public static void main(String... args) {
        HelloWorldAnonymousClasses myApp =
            new HelloWorldAnonymousClasses();
        myApp.sayHello();
    }            
}