Lamada expressions tips Introduction

Functional Programming

@FunctionalInterface
interface Lf{
    void dispaly();
}

@FunctionalInterface display programming interface defining a function, the function does not comply with the formula given programming interface 
anonymous inner classes use

public class FunPrograming {

	public static void main(String[] args) {
		func func = new func() {
			@Override
			public void dispaly() {
				// TODO Auto-generated method stub
				System.out.println("dispaly()运行");
			}
		};
		func.dispaly();
	}
}

dispaly()运行

　　lamada: copy parentheses, write death ->, landing braces {}

public class FunPrograming {

    public static void main(String[] args) {

        func func = ()->{
            System.out.println("dispaly()运行");
        };
        func.dispaly();
    }
}

dispaly () operation

 

Interface with return value

@FunctionalInterface
 interface FUNC { // Invalid '@FunctionalInterface' Annotation; FUNC IS A Not Functional interface defines two methods will be given general, do not meet the functional programming 
    public  void dispaly ();
     public  int   the Add ( int X, int Y); 
}

// copy parentheses, hardcoded ->, floor braces} { 
@FunctionalInterface
 interface FUNC {
     // public void dispaly (); 
    public  int   the Add ( int X, int Y) ; 
} 

public  class FunPrograming { 

    public  static  void main ( String [] args) { 
        FUNC FUNC = ( int X, int Y) -> { 
            the System. OUT .println ( " the Add (int X, Y int) operation " );
             return X +  Y;
        };
        System.out.println(func.add(3,5));
    }
}

add(int x,int y)运行
8

 

Functional programming interfaces, how to define a plurality of methods

@FunctionalInterface
interface func {
    default void dispaly() {
        System.out.println("default void dispaly()");
    }
    default int mul(int x ,int y) {
        System.out.println("default int mul");
        return x* y;
    }
    static int dec(int x,int y) {
        System.out.println("static int dec(int x,int y)");
        return x-y;
    }
    static int div(int x,int y) {
        System.out.println("static int div(int x,int y)");
        return x/y;
    }
    public int  add(int x,int y);
}