简单工厂 工厂方法 抽象工厂

简单工厂

package com.lucas.ModelSimpleFactory;

public abstract class Operation {
	public double A = 0;
	public double B = 0;

	public double getA() {
		return A;
	}

	public void setA(double a) {
		A = a;
	}

	public double getB() {
		return B;
	}

	public void setB(double b) {
		B = b;
	}

	public double getResult() {
		double result = 0;
		return result;
	}
}

package com.lucas.ModelSimpleFactory;

public class OperationAdd extends Operation{
@Override
	public double getResult() {
		double result = 0;
		result = A + B;
		return result;
	}
}

package com.lucas.ModelSimpleFactory;

public class OperationSub extends Operation{
	@Override
	public double getResult() {
		return A - B;
	}
}

package com.lucas.ModelSimpleFactory;

public class OperationFactory {
	public static Operation createOperate(int num) {
		Operation oper = null;
		
		switch(num) {
		case 1:
			oper = new OperationAdd();
			break;
		case 2:
			oper = new OperationSub();
			break;
		}
		
		return oper;
	}
}

 

工厂方法

如果要添加乘方的运算呢，无疑要在OperationFactory类内增加该运算，这明显违背了开闭原则和依赖倒转原则（细节依赖于抽象，抽象不依赖细节！）。怎么解决？可以将OperationFactory定义为接口，让具体的operation实现它，增加运算时只要增加一个实现类（继承Operation的类也要增加）！

抽象工厂

OperationFactory这样的抽象类有多个时，就叫抽象工厂了。