设计模式-简单工厂模式

 类图：

代码：

public class Operation {

    protected double numberA = 0;
    protected double numberB = 0;
    
    
    public double getNumberA() {
        return numberA;
    }
    public void setNumberA(double numberA) {
        this.numberA = numberA;
    }
    public double getNumberB() {
        return numberB;
    }
    public void setNumberB(double numberB) {
        this.numberB = numberB;
    }
    
    protected double getResult()
    {
        double result = 0;
        return result;
    }
    

}

public class AddOperation extends Operation{

    @Override
    public double getResult()
    {
        return numberA + numberB;
        
    }
    

}

public class OperationFactory {

    public static Operation createOperation(String operate)
    {
        if (operate.equals("+"))
        {
            return new AddOperation();
        }
        else if (operate.equals("*"))
        {
            return new MutiOperation();
        }
        return null;
    }
}

public class Client {

    public static void main(String[] args)
    {
        Operation add = OperationFactory.createOperation("+");
        add.setNumberA(1);
        add.setNumberB(2);
        System.out.println(add.getResult());
    }
}