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InterfaceClassExample.java
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184 lines (151 loc) · 3.97 KB
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package class_ex;
/**
* 繼承 interface 範例
*
*/
public class InterfaceClassExample {
public static void main(String[] args) {
// Airplane, Bird example.
Fly bird = new Bird("angry bird"); // upcasting
bird.flying();
bird.getName();
Fly airplane = new Airplane("Boeing 747 airplane"); // upcasting
airplane.flying();
airplane.getName();
// Car example. (主要理解default, static, private method in the interface class.)
Car<String> car = new Car<>("Toyota");
System.out.println("[Step 1] " + car.alarmOn());
System.out.println("[Step 2] " + car.getBrand());
System.out.println("[Step 3] " + car.run());
System.out.println("------------------------------------");
Car<String> result = car.execute();
System.out.println("execute time: " + result.getExecuteTime());
}
}
/**
* 使用單一 interface 介面來實作
* - interface: Fly
* - class: Bird, Airplane
*/
interface Fly {
void getName();
void flying();
}
class Bird implements Fly {
private String name;
Bird(String name) {
this.name = name;
}
@Override
public void getName() {
System.out.println("I am a " + name + ".");
}
@Override
public void flying() {
System.out.println("Bird is flying...");
}
}
class Airplane implements Fly {
private String name;
Airplane(String name) {
this.name = name;
}
public void getName() {
System.out.println("I am a " + name + ".");
}
public void flying() {
System.out.println("Airplane is flying...");
}
}
/**
* Interface class 規則與範例
* - 介面內 private method 存在時，可提供介面內程式碼重複使用。
* - 實作的類別將無法呼叫介面內 private method。
* - default method 則可以被實作類別呼叫。
*
* default 擴充interface新功能，如果不使用 default，interface不允許方法內有實作內容。
*/
interface Vehicle<T> {
String getBrand();
String run();
default String alarmOn() {
method1();
return "turn on alarm.";
}
default String alarmOff() {
return "turn off alarm.";
}
static int speedUp(int speed) {
return speed + 50;
}
/**
* 此 private method 只能被允許在介面內使用
*/
private void method1() {
method3();
System.out.println("This is a method 1.");
}
private void method2() {
System.out.println("This is a method 2.");
}
private void method3() {
System.out.println("This is a method 3.");
method2();
}
/**
* TODO: 是否可以使用通用介面來讓class繼承並實作細節
*/
public Vehicle<?> execute();
}
/**
* 實作 interface: Vehicle + Generic
*/
class Car<T> implements Vehicle<T> {
private String brand;
private int execute_time;
Car(String brand) {
this.brand = brand;
}
@Override
public String getBrand() {
return brand;
}
@Override
public String run() {
return "driving car safely.";
}
public Car<T> step4() {
System.out.println("call step 4.");
execute_time++;
return this;
}
public Car<T> step5() {
System.out.println("call step 5.");
execute_time++;
return this;
}
public Car<T> step6() {
System.out.println("call step 6.");
execute_time++;
return this;
}
public Car<T> reverseStep() {
System.out.println(" call reverse step.");
execute_time--;
return this;
}
@Override
public Car<T> execute() {
execute_time = 0;
this.step4()
.reverseStep()
.step5()
.step6()
.reverseStep();
// System.out.println("execute_time: " + execute_time);
return this;
}
public int getExecuteTime() {
return this.execute_time;
}
}