Shallow copy/Deep copy for contained objects[Answered] RSS

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  Van_003

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  Shallow copy/Deep copy for contained objects

  Jan 12, 2009 05:22 AM|Van_003|LINK

  I am creating a class that basically need to perform some operations on files after reading them.

  The class skeleton is like this

  class filesystem

  { private string fileName;

   private FileInfo fileInformation;

  private Dictionary<string,string> headers;

  }

  What is the best way to expose these member variables as properties ? The FileInfo object needs a string(file path) in its constructor

  1.If i do

  public FileInfo File

  {

  get { return file; }

  }

  I want a setter property also for my FileInfo Object. How do i accomplish it?

   

  2. public Dictionary<string, object> Headers

  {

  get { return headers; }

  set

  {

  if (headers == null) headers = new Dictionary<string, string>();headers = value;

  }

  }

  Is it right way to code setter property for thsi kind of collection ? If not, what is the right way ? I did this way because I felt simply doing headers=value would create a shallow copy.

   

  Please suggest.

   

  Thanks in advance

• • Reply
  SMHoff

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  30 Posts

  Re: Shallow copy/Deep copy for contained objects

  Jan 12, 2009 08:59 AM|SMHoff|LINK

   Well there's a couple questions there.

   Quote:
   "What is the best way to expose these member variables as properties ? The FileInfo object needs a string(file path) in its constructor"

   

  The best way really depends upon the situation. However, to simple set the variable you could do something like:
  

   

   

  public FileInfo MyFile
  {
     get{return this.myFile;}
     set
     {
         if (File.Exists(value.FullName))
         {
             this.myFile = value;
         }
      }
  }

  Remembering that you are exposing a FileInfo object, so you would be required to pass one to the property. What I'm guessing you'd like to do is pass

   a path or string to the property and create a new FileInfo instance. So what I would

  suggest is to leave only the getter and create a method on your class that accepts a string and handles the creation of the FileInfo object:

   
          private FileInfo myFileInfo;
  
          public void CreateFileInfo(string path)
          {
              if (!string.IsNullOrEmpty(path))
              {
                  if (File.Exists(path))
                  {
                      try
                      {
                          this.myFileInfo = new FileInfo(path);
                      }
                      catch (System.IO.IOException io)
                      {
                          // log exception or throw etc.
                      }
                  }
              }
          }

    Regarding the Dictionary question, you could follow the same pattern above.

    
          private Dictionary<string, string> myDictionary;
  
          public void CreateMyDictionary(string key, string value)
          {
              if ((!string.IsNullOrEmpty(key))&& (!string.IsNullOrEmpty(value)))
              {
                  if (this.myDictionary == null)
                  {
                      this.myDictionary = new Dictionary<string,string>();
                  }
  
                  if (!this.myDictionary.ContainsKey(key))
                  {
                      this.myDictionary.Add(key, value);
                  }
              }
          }
    

• • Reply
  Van_003

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  Re: Shallow copy/Deep copy for contained objects

  Jan 12, 2009 11:34 PM|Van_003|LINK

  Ok, That looks like a good idea.

  Just one confusion,

  If one were to do myDictionary = value on a dictionary object in a setter property, without acquiring memory for it specifically using new(),

  does it create a shallow copy , or does the framework itself manages to create a deep copy in this case ?

• • Reply
  anonymouswri...

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  Re: Shallow copy/Deep copy for contained objects

  Jan 13, 2009 04:13 AM|anonymouswrites|LINK

   I am not sure if it is a good practise or not but What I do mostly is something like this

  private Dictionary<int,string> myDic = new Dictionary<int,string>();

  public Dictionary<int,string> MyDic

  {

  get {return myDic;}

  set{myDic = value;}
  

  }