ex-08-02

Programming Csharp Source Code(代码) Programming Csharp Source Code

//Example 08-02: Extending and combining interfaces

using System;

interface IStorable
{
   void Read();
   void Write(object obj);
   int Status { get; set; }

}

// here's the new interface
interface ICompressible
{
   void Compress();
   void Decompress();
}

// Extend the interface
interface ILoggedCompressible : ICompressible
{
   void LogSavedBytes();
}

// Combine Interfaces
interface IStorableCompressible : IStorable, ILoggedCompressible
{
   void LogOriginalSize();
}

// yet another interface
interface IEncryptable
{
   void Encrypt();
   void Decrypt();
}

public class Document : IStorableCompressible, IEncryptable
{
   // the document constructor
   public Document(string s) 
   {
      Console.WriteLine("Creating document with: {0}", s);
        
   }
    
   // implement IStorable
   public void Read()
   {
      Console.WriteLine(
         "Implementing the Read Method for IStorable");        
   }

   public void Write(object o)
   {
      Console.WriteLine(
         "Implementing the Write Method for IStorable");  
   }

   public int Status
   {
      get
      {
         return status;
      }

      set
      {
         status = value;
      }
   }
    
   // implement ICompressible
   public void Compress() 
   { 
      Console.WriteLine("Implementing Compress"); 
   }
    
   public void Decompress() 
   { 
      Console.WriteLine("Implementing Decompress"); 
   }
    
   // implement ILoggedCompressible
   public void LogSavedBytes()
   {
      Console.WriteLine("Implementing LogSavedBytes");
   }   
    
   // implement IStorableCompressible 
   public void LogOriginalSize()
   {
      Console.WriteLine("Implementing LogOriginalSize");
   }

   // implement IEncryptable
   public void Encrypt()
   {
      Console.WriteLine("Implementing Encrypt");
        
   }

   public void Decrypt()
   {
      Console.WriteLine("Implementing Decrypt");
        
   }

   // hold the data for IStorable's Status property
   private int status = 0;
}

public class Tester
{
 
   static void Main()
   {
      // create a document object
      Document doc = new Document("Test Document");

      // cast the document to the various interfaces
      IStorable isDoc = doc as IStorable;
      if (isDoc != null)
      {
         isDoc.Read();
      }
      else
         Console.WriteLine("IStorable not supported");
        
      ICompressible icDoc = doc as ICompressible;
      if (icDoc != null)
      {
         icDoc.Compress();
      }
      else
         Console.WriteLine("Compressible not supported");

      ILoggedCompressible ilcDoc = doc as ILoggedCompressible;
      if (ilcDoc != null)
      {
         ilcDoc.LogSavedBytes();
         ilcDoc.Compress();
         // ilcDoc.Read();
      }
      else
         Console.WriteLine("LoggedCompressible not supported");

      IStorableCompressible isc = doc as IStorableCompressible;
      if (isc != null)
      {
         isc.LogOriginalSize();  // IStorableCompressible
         isc.LogSavedBytes();    // ILoggedCompressible
         isc.Compress();         // ICompressible
         isc.Read();             // IStorable

      }
      else
      {
         Console.WriteLine("StorableCompressible not supported");
      }

      IEncryptable ie = doc as IEncryptable;
      if (ie != null)
      {
         ie.Encrypt();
      }
      else
         Console.WriteLine("Encryptable not supported");
   }
}