Java 多态 polymorphic 枚举 练习

　　

 

 

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package ersatz;   public class Car {   private double temperature;     public Car(double temperature) {     this.temperature = temperature;   }     private class Air {     public void tune() {       if (temperature >= 40) {         System.out.println("cold air");       } else if (temperature < 0) {         System.out.println("warm air");       } else {         System.out.println("nothing");       }     }   }     public Air getAir() {     return new Air();   }     public static void main(String[] args) {     final Car car = new Car(50);     car.getAir().tune();     final Car car1 = new Car(-5);     car1.getAir().tune();     final Car car2 = new Car(33);     car2.getAir().tune();   } }

　　

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package ersatz;   public class Car {   private double temperature;     public Car(double temperature) {     this.temperature = temperature;   }     private class Air {     public void tune() {       if (temperature >= 40) {         System.out.println("cold air");       } else if (temperature < 0) {         System.out.println("warm air");       } else {         System.out.println("nothing");       }     }   }     public void regulate() {     new Air().tune();   }     public static void main(String[] args) {     final Car car = new Car(50);     car.regulate();     final Car car1 = new Car(-5);     car1.regulate();     final Car car2 = new Car(33);     car2.regulate();   } }

　　

 

 

 

Vehicle.java

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package com.gibe;   public interface Vehicle {   public abstract void work(); }

　　

Horse.java

　　

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package com.gibe;   public class Horse implements Vehicle{   @Override   public void work(){     System.out.println("use horse");   } }

　　

Boat.java

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package com.gibe;   public class Boat implements Vehicle{   @Override   public void work(){     System.out.println("use boat");   } }

　　

Plane.java

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package com.gibe;   public class Plane implements Vehicle{   @Override   public void work() {     System.out.println("use plane");   } }

　　

VehicleFactory.java

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package com.gibe;   public class VehicleFactory {   private static Horse horse = null;   private static final Boat boat = new Boat();     private VehicleFactory() {   }     public static Horse getHorse() {     if (horse == null) {       horse = new Horse();     }     return horse;   }     public static Boat getBoat() {     return boat;   }     public static Plane getPlane() {     return new Plane();   } }

　　

Person.java

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package com.gibe;   public class Person {   private String name;   private Vehicle vehicle;     public Person(String name, Vehicle vehicle) {     this.name = name;     this.vehicle = vehicle;   }     public void river() {     if (!(this.vehicle instanceof Boat)) {       vehicle = VehicleFactory.getBoat();     }     vehicle.work();   }     public void land() {     if (!(vehicle instanceof Horse)) {       vehicle = VehicleFactory.getHorse();     }     vehicle.work();   }     public void fire() {     if (!(vehicle instanceof Plane)) {       vehicle = VehicleFactory.getPlane();     }     vehicle.work();   } }

　　

Test

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package ersatz;     import com.gibe.Person; import com.gibe.VehicleFactory;   public class Ersatz {   @SuppressWarnings({"SpellCheckingInspection"})   public static void main(String[] args) {     final Person bb = new Person("bb", VehicleFactory.getHorse());     bb.land();     bb.river();     bb.fire();     bb.river();   } }

　　

 

 

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package com.gibe;   public class Ersatz {   public static void main(String[] args) {     Color green = Color.GREEN;     green.show();     switch (green) {       case YELLOW:         System.out.println("yellow");         break;       case BLACK:         System.out.println("black");         break;       default:         System.out.println("none");         break;     }   } }     enum Color implements Interface {   RED(255, 0, 0), BLUE(0, 0, 255),   BLACK(0, 0, 0), YELLOW(255, 255, 0),   GREEN(0, 255, 0);   private final int red;   private final int green;   private final int blue;     private Color(int red, int green, int blue) {     this.red = red;     this.green = green;     this.blue = blue;   }     @Override   public void show() {     System.out.println("red=" + red + ", green=" + green + ", blue=" + blue);   } }   interface Interface {   public abstract void show(); }