Ref-Gonçalo Marques
Introduction
java中的接口有时也可以通过枚举类型来实现。
The Enum
这里以一个简单的数学算法为例。首先我们定义一个运算的接口。
Operator.java
public interface Operator {
int calculate(int firstOperand, int secondOperand);
}
接下来我们定义一个实现上面接口的枚举类型。
EOperator.java
public enum EOperator implements Operator {
SUM {
@Override
public int calculate(int firstOperand, int secondOperand) {
return firstOperand + secondOperand;
}
},
SUBTRACT {
@Override
public int calculate(int firstOperand, int secondOperand) {
return firstOperand - secondOperand;
}
};
}
接下来定义一个operation class
public class Operation {
private int firstOperand;
private int secondOperand;
private EOperator operator;
public Operation(int firstOperand, int secondOperand,
EOperator operator) {
this.firstOperand = firstOperand;
this.secondOperand = secondOperand;
this.operator = operator;
}
public int calculate(){
return operator.calculate(firstOperand, secondOperand);
}
}
最后测试：
public class Main {
public static void main (String [] args){
Operation sum = new Operation(10, 5, EOperator.SUM);
Operation subtraction = new Operation(10, 5, EOperator.SUBTRACT);
System.out.println("Sum: " + sum.calculate());
System.out.println("Subtraction: " + subtraction.calculate());
}
}
