设计模式之工厂方法模式

package com.hml.factory.method;

public abstract class Operation {

    private int numberA;
    private int numberB;

    public int getNumberA() {
        return numberA;
    }

    public void setNumberA(int numberA) {
        this.numberA = numberA;
    }

    public int getNumberB() {
        return numberB;
    }

    public void setNumberB(int numberB) {
        this.numberB = numberB;
    }

    public abstract int getResult();
}

package com.hml.factory.method;

public class AddOperation extends Operation {

    public int getResult() {
        return getNumberA() + getNumberB();
    }

}

package com.hml.factory.method;

public class SubOperation extends Operation {

    public int getResult() {
        return getNumberA() - getNumberB();
    }

}

package com.hml.factory.method;

public interface IFactory {
    public Operation createOperation();
}

package com.hml.factory.method;

public class AddOperationFactory implements IFactory {

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

}

package com.hml.factory.method;

public class SubOperationFactory implements IFactory {
    public Operation createOperation() {
        return new SubOperation();
    }
}