/// <summary>
/// The 'Flyweight' interface
///享元模式 Flyweight Pattern
/// geovindu,Geovin Du edit
/// 车辆
/// </summary>
interface IVehicle
{
/*
* Client will supply the color.
* It is extrinsic state.
*/
/// <summary>
///
/// </summary>
/// <param name="color">输入颜色</param>
void AboutMe(string color);
}
/// <summary>
/// A 'ConcreteFlyweight' class called Car
/// 汽车
/// </summary>
class Car : IVehicle
{
/*
* It is intrinsic state and
* it is independent of flyweight context.
* this can be shared.So, our factory method will supply
* this value inside the flyweight object.
*/
/// <summary>
/// 描述
/// </summary>
private string description;
/*
* Flyweight factory will supply this
* inside the flyweight object.
*/
/// <summary>
///
/// </summary>
/// <param name="description">输入描述</param>
public Car(string description)
{
this.description = description;
}
//Client will supply the color
/// <summary>
///
/// </summary>
/// <param name="color">输入颜色</param>
public void AboutMe(string color)
{
Console.WriteLine($"{description} 为 {color} .");
}
}
/// <summary>
/// A 'ConcreteFlyweight' class called Bus
/// 公交车
/// </summary>
class Bus : IVehicle
{
/*
* It is intrinsic state and
* it is independent of flyweight context.
* this can be shared.So, our factory method will supply
* this value inside the flyweight object.
*/
/// <summary>
/// 描述
/// </summary>
private string description;
/// <summary>
///
/// </summary>
/// <param name="description">输入描述</param>
public Bus(string description)
{
this.description = description;
}
//Client will supply the color
/// <summary>
///
/// </summary>
/// <param name="color">输入颜色</param>
public void AboutMe(string color)
{
Console.WriteLine($"{description} 为 {color} .");
}
}
/// <summary>
/// A 'ConcreteFlyweight' class called FutureVehicle
/// 未来车辆
/// </summary>
class FutureVehicle : IVehicle
{
/*
* It is intrinsic state and
* it is independent of flyweight context.
* this can be shared.So, our factory method will supply
* this value inside the flyweight object.
*/
/// <summary>
/// 描述
/// </summary>
private string description;
/// <summary>
///
/// </summary>
/// <param name="description">输入描述</param>
public FutureVehicle(string description)
{
this.description = description;
}
//Client cannot choose color for FutureVehicle
//since it's unshared flyweight,ignoring client's input
/// <summary>
///
/// </summary>
/// <param name="color">输入颜色</param>
public void AboutMe(string color)
{
Console.WriteLine($"{description} 为 {color} .");
}
}
/// <summary>
/// The factory class for flyweights implemented as singleton.
/// 车辆工厂类
/// </summary>
class VehicleFactory
{
/// <summary>
///
/// </summary>
private static readonly VehicleFactory Instance = new VehicleFactory();
/// <summary>
///
/// </summary>
private Dictionary<string, IVehicle> vehicles = new Dictionary<string, IVehicle>();
/// <summary>
///
/// </summary>
private VehicleFactory()
{
vehicles.Add("小汽车", new Car("一辆小汽车制造"));
vehicles.Add("公交车", new Bus("一辆公交车制造"));
vehicles.Add("概念车", new FutureVehicle("概念车 T2050 制造"));
}
/// <summary>
///
/// </summary>
public static VehicleFactory GetInstance
{
get
{
return Instance;
}
}
/*
* To count different type of vehicle
* in a given moment.
*/
/// <summary>
/// 数量
/// </summary>
public int TotalObjectsCreated
{
get
{
return vehicles.Count;
}
}
/// <summary>
///
/// </summary>
/// <param name="vehicleType"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
public IVehicle GetVehicleFromVehicleFactory(string vehicleType)
{
IVehicle vehicleCategory = null;
if (vehicles.ContainsKey(vehicleType))
{
vehicleCategory = vehicles[vehicleType];
return vehicleCategory;
}
else
{
throw new Exception("Currently, the vehicle factory can have cars and buses only.");
}
}
}
/// <summary>
///享元模式 Flyweight Pattern
/// geovindu,Geovin Du edit
/// </summary>
public class FormattedText
{
/// <summary>
///
/// </summary>
private readonly string plainText;
/// <summary>
///
/// </summary>
/// <param name="plainText"></param>
public FormattedText(string plainText)
{
this.plainText = plainText;
capitalize = new bool[plainText.Length];
}
/// <summary>
///
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
public void Capitalize(int start, int end)
{
for (int i = start; i <= end; ++i)
capitalize[i] = true;
}
/// <summary>
///
/// </summary>
private readonly bool[] capitalize;
/// <summary>
/// 大写
/// </summary>
/// <returns></returns>
public override string ToString()
{
var sb = new StringBuilder();
for (var i = 0; i < plainText.Length; i++)
{
var c = plainText[i];
sb.Append(capitalize[i] ? char.ToUpper(c) : c);
}
return sb.ToString();
}
}
/// <summary>
///
/// </summary>
public class BetterFormattedText
{
private readonly string plainText;
private readonly List<TextRange> formatting
= new List<TextRange>();
/// <summary>
///
/// </summary>
/// <param name="plainText"></param>
public BetterFormattedText(string plainText)
{
this.plainText = plainText;
}
/// <summary>
///
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
/// <returns></returns>
public TextRange GetRange(int start, int end)
{
var range = new TextRange { Start = start, End = end };
formatting.Add(range);
return range;
}
/// <summary>
/// 大写
/// </summary>
/// <returns></returns>
public override string ToString()
{
var sb = new StringBuilder();
for (var i = 0; i < plainText.Length; i++)
{
var c = plainText[i];
foreach (var range in formatting)
if (range.Covers(i) && range.Capitalize)
c = char.ToUpperInvariant(c);
sb.Append(c);
}
return sb.ToString();
}
/// <summary>
///
/// </summary>
public class TextRange
{
public int Start, End;
public bool Capitalize, Bold, Italic;
public bool Covers(int position)
{
return position >= Start && position <= End;
}
}
}
调用：
//享元模式 Flyweight Pattern
Console.WriteLine("***享元模式 Flyweight Pattern Demo.***\n");
//VehicleFactory vehiclefactory = new VehicleFactory();
VehicleFactory vehiclefactory = VehicleFactory.GetInstance;
IVehicle vehicle;
/*
* Now we are trying to get the 3 cars.
* Note that:we need not create additional cars if
* we have already created one of this category
*/
for (int i = 0; i < 3; i++)
{
vehicle = vehiclefactory.GetVehicleFromVehicleFactory("小汽车");
vehicle.AboutMe("绿色");
}
int numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;
Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");
/*Here we are trying to get the 5 more buses.
* Note that: we need not create
* additional buses if we have
* already created one of this category */
for (int i = 0; i < 5; i++)
{
vehicle = vehiclefactory.GetVehicleFromVehicleFactory("公交车");
vehicle.AboutMe("红色");
}
numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;
Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");
/*Here we are trying to get the 2 future vehicles.
* Note that: we need not create
* additional future vehicle if we have
* already created one of this category */
for (int i = 0; i < 2; i++)
{
vehicle = vehiclefactory.GetVehicleFromVehicleFactory("概念车");
vehicle.AboutMe("白色");
}
numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;
Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");
#region test for in-built flyweight pattern
Console.WriteLine("**Testing String interning in .NET now.**");
string firstString = "A simple string";
string secondString = new StringBuilder().Append("A").Append(" simple").Append(" string").ToString();
string thirdString = String.Intern(secondString);
Console.WriteLine((Object)secondString == (Object)firstString); // Different references.
Console.WriteLine((Object)thirdString == (Object)firstString); // The same reference.
#endregion
//大写
var ft = new FormattedText("This is a geovindu new world");
ft.Capitalize(10, 17);
Console.WriteLine(ft);
//大写
var bft = new BetterFormattedText("This is a lukfook new world");
bft.GetRange(10, 16).Capitalize = true;
Console.WriteLine(bft);
Console.ReadKey();
输出：
***享元模式 Flyweight Pattern Demo.*** 一辆小汽车制造 为 绿色 . 一辆小汽车制造 为 绿色 . 一辆小汽车制造 为 绿色 . Now, total numbers of distinct vehicle object(s) is = 3 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . Now, total numbers of distinct vehicle object(s) is = 3 概念车 T2050 制造 为 白色 . 概念车 T2050 制造 为 白色 . Now, total numbers of distinct vehicle object(s) is = 3 **Testing String interning in .NET now.** False True This is a GEOVINDU new world This is a LUKFOOK new world