COR模式（责任链模式）

模式简介

责任链模式多用于对一个对象的不同处理流程，不同处理流程构成一个责任链，按照顺序依次对该对象进行处理。

模式UML图

代码示例（C#）

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    //等级条件，继承Conditionpublic class LevelCondition : Condition{public LevelCondition(string p_name){name = p_name;}public override bool Judge(Player p_player){if (p_player.level < 25){Console.WriteLine("The player " + p_player.name + " not meets level condition.");return false;}Console.WriteLine("The player " + p_player.name + " meets level condition.");return true;}}//成就条件，继承Conditionpublic class AchievementCondition : Condition{public AchievementCondition(string p_name){name = p_name;}public override bool Judge(Player p_player){if (p_player.achievement < 30){Console.WriteLine("The player " + p_player.name + " not meets achievement condition.");return false;}Console.WriteLine("The player " + p_player.name + " meets achievement condition.");return true;}}//任务条件，继承Conditionpublic class TaskCondition : Condition{public TaskCondition(string p_name){name = p_name;}public override bool Judge(Player p_player){if (p_player.task < 50){Console.WriteLine("The player " + p_player.name + " not meets task condition.");return false;}Console.WriteLine("The player " + p_player.name + " meets task condition.");return true;}}//抽象条件，实现ICondition接口public abstract class Condition : ICondition{protected string name;public abstract bool Judge(Player p_player);}//条件和条件链需要实现该接口public interface ICondition{public bool Judge(Player p_player);}//条件链，实现ICondition接口public class ConditionChain : ICondition{private List<ICondition> conditionChain = new List<ICondition>();public void Add(ICondition p_condition){conditionChain.Add(p_condition);}public bool Judge(Player p_player){foreach (ICondition c in conditionChain){if (!c.Judge(p_player)) return false;}return true;}public void Remove(ICondition p_condition){conditionChain.Remove(p_condition);}}//玩家类public class Player{public string name;public int level;public int achievement;public int task;public Player(string p_name, int p_level, int p_achievement, int p_task){name = p_name;level = p_level;achievement = p_achievement;task = p_task;}}//测试代码public void Test(){LevelCondition levelConditon = new LevelCondition("等级条件");AchievementCondition achievementCondition = new AchievementCondition("成就条件");TaskCondition taskCondition = new TaskCondition("任务条件");ConditionChain chain1 = new ConditionChain();ConditionChain chain2 = new ConditionChain();chain1.Add(levelConditon);chain1.Add(achievementCondition);chain2.Add(taskCondition);chain1.Add(chain2);Player kaka = new Player("Kaka", 33, 30, 55);Player jojo = new Player("JoJo", 25, 30, 30);Console.WriteLine("【KaKa】");var res = conditionChain.Judge(kaka);Console.WriteLine("IsPass:" + res);Console.WriteLine("【JoJo】");res = conditionChain.Judge(jojo);Console.WriteLine("IsPass:" + res);}

代码解说

责任链模式，通常用于对一个对象的多种分步处理，例如对于用户输入的信息在保存至DB前进行筛选和替换，或者一个游戏活动要求判断玩家等级、成就、任务达到要求才能领取奖励等等，责任链可以自由添加和删除处理流程，并且还支持将责任链作为添加和删除的对象，简而言之就是责任链之间也可以进行连接。当然还有更复杂的责任链模式结合递归，例如Java中的Filter。本案例中要求玩家的等级LevelCondition、成就AchievementCondition、任务TaskCondition分别达到对应条件才可以领取奖励，chain1和chain2都是责任链，既可以添加单个条件，二者也可以进行拼接。

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