Slogger - The simple extensible logger

using System ;
using System.IO ;
using System.Xml ;
using System.Xml.XPath ;

namespace Slogger.Utilities
{
  public class SettingsReader
  {
    XPathNavigator _navigator;
    protected XPathNavigator Navigator { get { return _navigator ; } }

    public XPathNavigator CloneNavigator( ) { return _navigator.Clone( ) ; }

    #region Constructors

    public SettingsReader( ) { }

    public SettingsReader( XPathNavigator xpathNavigator )
    {
      Initialise( xpathNavigator ) ;
    }

    public SettingsReader( string filename)
    {
      Initialise( filename ) ;
    }

    public SettingsReader(XPathDocument xpathDocument )
    {
      Initialise( xpathDocument ) ;
    }
    
    public SettingsReader( StreamReader streamReader )
    {
      Initialise( streamReader ) ;
    }
    #endregion

    #region Initialisers

    public void Initialise( XPathNavigator xpathNavigator )
    {
      if ( xpathNavigator == null )
        throw new NullReferenceException( "Cannot initialise SettingsReader with a null XPathNavigator" ) ;

      _navigator = xpathNavigator ;
    }

    public void Initialise( StreamReader streamReader )
    {
      XmlTextReader r = new XmlTextReader( streamReader ) ;
      r.WhitespaceHandling=WhitespaceHandling.Significant;

      XPathDocument document = new XPathDocument(r ) ;
      _navigator= document.CreateNavigator( ) ;
    }

    public void Initialise( XPathDocument xpathDocument )
    {
      _navigator = xpathDocument.CreateNavigator( ) ;
    }

    public void Initialise( string filename )
    {
      Initialise ( new StreamReader( filename ) ) ;
    }
    #endregion

    public bool SetRoot( string root )
    {
      XPathNodeIterator it = _navigator.Select( root ) ;
      if ( it.Count==0)
        return false ;
      it.MoveNext( ) ;
      _navigator = it.Current.Clone( ) ;
      return true;
    }

    public void SetRoot( )
    {
      _navigator.MoveToRoot( ) ;
    }

    public void SetRoot( XPathNavigator navigator )
    {
      _navigator = navigator.Clone( ) ;
    }

    public bool Exists(string path)
    {
      string s = path.Replace(".", "/" ) ;
      XPathNavigator nav = _navigator.Clone( ) ;
      XPathNodeIterator it = nav.Select( s ) ;
      return it.Count == 0 ? false : true ;
    }
    
    public object GetValue(string path)
    {
      string s = path.Replace(".", "/" ) ;
      XPathNodeIterator it = _navigator.Select( s ) ;
      if ( it.Count== 0 )
        throw new Exception(string.Format("Cannot find the value of node: {0}", path ) ) ;
      it.MoveNext( ) ;
      return it.Current.Value;
    }

    public object this[string path]
    {
      get
      {
        //SEE IF THERE'S AN @ IN THERE TO GET AN ATTRIBUTE
        int n = path.LastIndexOf("@");
        if ( n != -1 )
          return GetAttribute( path.Substring(0,n)+path.Substring(n+1) ) ;
        return GetValue( path ) ;
      }
    }


    public object GetAttribute(string path)
    {
      string s = path.Replace(".", "/" ) ;

      int n = s.LastIndexOf("/");
      if ( n == -1 )
        return Navigator.GetAttribute( s, "" ) ;

      string s2 = s.Substring(0,n);
      string satt=s.Substring(n+1  ) ;
      XPathNodeIterator it = _navigator.Select( s2 ) ;
      if ( it.Count== 0 )
        throw new Exception(string.Format("Cannot get attribute.  Node:{0} not found", s2 ) ) ;

      it.MoveNext( ) ;
      return it.Current.GetAttribute(satt, "" ) ;
    }
  }
}