Question

I have a log tool for my applications. I log to XML in a hierarchical manner (this means that I can nest log items). My Log(string, bool) takes two parameters, one with the string to log and a bool value determining if this comment should be nested below the previous log comment. A PopLog() method is made to go to the parent, and continue logging on the parent level.

This means that when I log like this:

Log("first", false);
...
Log("Second", true);
...
Log("Third", true);
PopLog();
PopLog();
PopLog();

This gives the following result:

<first>
  <second>
    <third>
  </second>
</first>

The problem I have with the current design is it is hard to keep track of my log level, how deep I am in the logging tree, and whether or not I need to pop, log using true, or log using false.

Any good ideas on how to make this simpler, more maintainable and better (changing log provider is not an option)?

Answer 1

A better design would be, IMO, to separate the push/pop behaviour from the logging itself. Here’s a solution in C#, using IDisposable:

 class IndentedLog : IDisposable
 {
    public IndentedLog() 
    {
       Log.IndentLevel++; 
    }
    public void Dispose() 
    {
       Log.IndentLevel--;
    }
 }

This way, you can do something like:

     Log("first");
     // ...
     using (new IndentedLog())
     {
         Log("second");
         // ...
         using (new IndentedLog()) 
         {
            Log("third");
         }
     }