摘录自：设计模式与游戏完美开发
十年磨一剑，作者将设计模式理论巧妙地融入到实践中，以一个游戏的完整实现呈现设计模式的应用及经验的传承 《轩辕剑》之父——蔡明宏、资深游戏制作人——李佳泽、Product Evangelist at Unity Technologies——Kelvin Lo、信仁软件设计创办人—— 赖信仁、资深3D游戏美术——刘明恺 联合推荐全书采用了整合式的项目教学，即以一个游戏的范例来应用23种设计模式的实现贯穿全书，让读者学习到整个游戏开发的全过程和作者想要传承的经验，并以浅显易懂的比喻来解析难以理解的设计模式，让想深入了解此领域的读者更加容易上手。
工程GitHub
FLYWEIGHT—每天跟MM发短信，手指都累死了，最近买了个新手机，可以把一些常用的句子存在手机里，要用的时候，直接拿出来，在前面加上MM的名字就可以发送了，再不用一个字一个字敲了。共享的句子就是Flyweight，MM的名字就是提取出来的外部特征，根据上下文情况使用。
享元模式：FLYWEIGHT在拳击比赛中指最轻量级。享元模式以共享的方式高效的支持大量的细粒度对象。享元模式能做到共享的关键是区分内蕴状态和外蕴状态。内蕴状态存储在享元内部，不会随环境的改变而有所不同。外蕴状态是随环境的改变而改变的。外蕴状态不能影响内蕴状态，它们是相互独立的。将可以共享的状态和不可以共享的状态从常规类中区分开来，将不可以共享的状态从类里剔除出去。客户端不可以直接创建被共享的对象，而应当使用一个工厂对象负责创建被共享的对象。享元模式大幅度的降低内存中对象的数量。
using UnityEngine;
using System.Collections.Generic;
namespace DesignPattern_Flyweight
{
// 可以被共用的Flyweight介面
public abstract class Flyweight
{
protected string m_Content; //显示的內容
public Flyweight(){}
public Flyweight(string Content)
{
m_Content= Content;
}
public string GetContent()
{
return m_Content;
}
public abstract void Operator();
}
// 共用的元件
public class ConcreteFlyweight : Flyweight
{
public ConcreteFlyweight(string Content):base( Content )
{
}
public override void Operator()
{
Debug.Log("ConcreteFlyweight.Content["+m_Content+"]");
}
}
// 不共用的元件(可以不必继承)
public class UnsharedConcreteFlyweight //: Flyweight
{
Flyweight m_Flyweight = null; // 共享的元件
string m_UnsharedContent; // 不共享的元件
public UnsharedConcreteFlyweight(string Content)
{
m_UnsharedContent = Content;
}
// 设定共享的元件
public void SetFlyweight(Flyweight theFlyweight)
{
m_Flyweight = theFlyweight;
}
public void Operator()
{
string Msg = string.Format("UnsharedCoincreteFlyweight.Content[{0}]",m_UnsharedContent);
if( m_Flyweight != null)
Msg += "包含了：" + m_Flyweight.GetContent();
Debug.Log(Msg);
}
}
// 负责产生Flyweight的工厂介面
public class FlyweightFactor
{
Dictionary<string,Flyweight> m_Flyweights = new Dictionary<string,Flyweight>();
// 取得共用的元件
public Flyweight GetFlyweight(string Key,string Content)
{
if( m_Flyweights.ContainsKey( Key) )
return m_Flyweights[Key];
// 产生并且设定內容
ConcreteFlyweight theFlyweight = new ConcreteFlyweight( Content );
m_Flyweights[Key] = theFlyweight;
Debug.Log ("New ConcreteFlyweigh Key["+Key+"] Content["+Content+"]");
return theFlyweight;
}
// 取得元件(只取得不共用的Flyweight)
public UnsharedConcreteFlyweight GetUnsharedFlyweight(string Content)
{
return new UnsharedConcreteFlyweight( Content);
}
// 取得元件(包含共用部份的Flyweight)
public UnsharedConcreteFlyweight GetUnsharedFlyweight(string Key,string SharedContent,string UnsharedContent)
{
// 先取得共用的部份
Flyweight SharedFlyweight = GetFlyweight(Key, SharedContent);
// 产出元件
UnsharedConcreteFlyweight theFlyweight = new UnsharedConcreteFlyweight( UnsharedContent);
theFlyweight.SetFlyweight( SharedFlyweight ); // 設定共享的部份
return theFlyweight;
}
}
}
using UnityEngine;
using System.Collections;
using DesignPattern_Flyweight;
public class FlyweightTest : MonoBehaviour {
// Use this for initialization
void Start () {
UnitTest();
}
void UnitTest () {
// 元件工廠
FlyweightFactor theFactory = new FlyweightFactor();
// 产生共用元件
theFactory.GetFlyweight("1","共用元件1");
theFactory.GetFlyweight("2","共用元件1");
theFactory.GetFlyweight("3","共用元件1");
// 取得一個共用元件
Flyweight theFlyweight = theFactory.GetFlyweight("1","");
theFlyweight.Operator();
// 产生不共用的元件
UnsharedConcreteFlyweight theUnshared1 = theFactory.GetUnsharedFlyweight("不共用的资讯1");
theUnshared1.Operator();
// 设定共用元件
theUnshared1.SetFlyweight( theFlyweight );
// 产生不共用的元件2,並指定使用共用元件１
UnsharedConcreteFlyweight theUnshared2 = theFactory.GetUnsharedFlyweight("1","","不共用的资讯2");
// 同时显示
theUnshared1.Operator();
theUnshared2.Operator();
}
}
