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POStrategy and Flyweight patterns
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  1. POStrategy and Flyweight patterns
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    copied!<p>I've read that "Strategy objects often make good flyweights" (from <em>Design Patterns Elements of Reusable Object-Oriented Software</em>), and I'm wondering how can this be implemented. I didn't find any example in the Internet.</p> <p>Is the code (C#) below right, following this idea?</p> <p>Thanks!</p> <pre><code>using System; using System.Collections.Generic; namespace StrategyFlyweight { class Program { static void Main(string[] args) { Client client = new Client(); for(int i = 1; i &lt;= 10;i++) { client.Execute(i); } Console.ReadKey(); } } public interface IStrategy { void Check(int number); } public class ConcreteStrategyEven : IStrategy { public void Check(int number) { Console.WriteLine("{0} is an even number...", number); } } public class ConcreteStrategyOdd : IStrategy { public void Check(int number) { Console.WriteLine("{0} is an odd number...", number); } } public class FlyweightFactory { private Dictionary&lt;string, IStrategy&gt; _sharedObjects = new Dictionary&lt;string, IStrategy&gt;(); public IStrategy GetObject(int param) { string key = (param % 2 == 0) ? "even" : "odd"; if (_sharedObjects.ContainsKey(key)) return _sharedObjects[key]; else { IStrategy strategy = null; switch (key) { case "even": strategy = new ConcreteStrategyEven(); break; case "odd": strategy = new ConcreteStrategyOdd(); break; } _sharedObjects.Add(key, strategy); return strategy; } } } public class Client { private IStrategy _strategy; private FlyweightFactory _flyweightFactory = new FlyweightFactory(); public void Execute(int param) { ChangeStrategy(param); _strategy.Check(param); } private void ChangeStrategy(int param) { _strategy = _flyweightFactory.GetObject(param); } } } </code></pre>
 

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