不知所谓的用函数对象表示策略
只是去看了下策略模式:菜鸟教程http://www.runoob.com/design-pattern/strategy-pattern.html
步骤 1
创建一个接口。
public interface Strategy {
public int doOperation(int num1, int num2);
}
步骤 2
创建实现接口的实体类。
//实体类一
public class OperationAdd implements Strategy{
@Override
public int doOperation(int num1, int num2) {
return num1 + num2;
}
}
//实体类二
public class OperationSubstract implements Strategy{
@Override
public int doOperation(int num1, int num2) {
return num1 - num2;
}
}
步骤 3
创建 Context 类。
public class Context {
private Strategy strategy;
public Context(Strategy strategy){
this.strategy = strategy;
}
public int executeStrategy(int num1, int num2){
return strategy.doOperation(num1, num2);
}
}
步骤 4
使用 Context 来查看当它改变策略 Strategy 时的行为变化。
public class StrategyPatternDemo {
public static void main(String[] args) {
Context context = new Context(new OperationAdd());
System.out.println("10 + 5 = " + context.executeStrategy(10, 5));
context = new Context(new OperationSubstract());
System.out.println("10 - 5 = " + context.executeStrategy(10, 5));
context = new Context(new OperationMultiply());
System.out.println("10 * 5 = " + context.executeStrategy(10, 5));
}
}