设计模式学习之工厂方法模式

1.名词解释

工厂方法模式，定义一个用于创建对象的接口，让子类决定实例化哪一个类。工厂方法使一个类的实例化延迟到其子类。

 

2.代码示例

工厂接口
package DesignPattern.FactoryMethodPattern;

public interface IFactory {
	
	public Operation createOperation() ;
}

 

加法工厂
package DesignPattern.FactoryMethodPattern;

public class AddFactory implements IFactory {

	@Override
	public Operation createOperation() {
		return new AddOperation();
	}

}

 

乘法工厂
package DesignPattern.FactoryMethodPattern;

public class MulFactory implements IFactory {

	@Override
	public Operation createOperation() {
		return new MulOperation();
	}
}

 

package DesignPattern.FactoryMethodPattern;

public class Operation {

	private double numberA = 0.0d;
	private double numberB = 0.0d;
	
	public void setNumberA(double d) {
		this.numberA = d;
	}
	
	public double getNumberA() {
		return this.numberA;
	}
	
	public void setNumberB(double d) {
		this.numberB = d;
	}
	
	public double getNumberB() {
		return this.numberB;
	}
	
	public double getResult() {
		return 0.0;
	}
}

 

加法处理类
package DesignPattern.FactoryMethodPattern;

public class AddOperation extends Operation {

	public double getResult() {
		return super.getNumberA() + super.getNumberB();
	}
}

 

乘法处理类
package DesignPattern.FactoryMethodPattern;

public class MulOperation extends Operation{

	public double getResult() {
		return super.getNumberA() * super.getNumberB();
	}
}

 

 

主控程序
package DesignPattern.FactoryMethodPattern;

public class Client {

	public static void main(String[] args) {
		IFactory factory = new AddFactory();
		Operation operation = factory.createOperation();
		double numberA = 2;
		double numberB = 12.9;
		operation.setNumberA(numberA);
		operation.setNumberB(numberB);
		double result = operation.getResult();
		System.out.println(result);
		
		factory = new MulFactory();
	    operation = factory.createOperation();
	    operation.setNumberA(numberA);
		operation.setNumberB(numberB);
	    result = operation.getResult();
	    System.out.println(result);
	}
}