#ifndef __creaImageIOTreeHandler_h_INCLUDED__
#define __creaImageIOTreeHandler_h_INCLUDED__

#include <creaImageIOTree.h>

namespace creaImageIO
{

/**
	* \ingroup Model
	*/
  //=======================================================================
  /// Abstract class which 'handles' a Tree structure 
  class TreeHandler
  {
  public:
    ///====================================================================
    /// Ctor
    TreeHandler() {}
    /// Virtual dtor
    virtual ~TreeHandler() {}
    ///====================================================================

    ///====================================================================
    /// Returns the Tree handled 
    tree::Tree& GetTree() { return mTree; }
    /// Returns the Tree handled (const)
    const tree::Tree& GetTree() const { return mTree; }
    ///====================================================================

    ///====================================================================
    /// QUERY METHODS
    /// Is the 'source' readable ?
    virtual bool IsReadable() { return false; }
    /// Is the 'source' writable ?
    virtual bool IsWritable() { return false; }
    ///====================================================================


    ///====================================================================
    /// INITIALIZATION / FINALIZATION
    ///====================================================================

    ///====================================================================
    /// Opens an existing 'source' 
    /// Default mode is read only 
    /// If IsWritable and writable==true then opens in read/write mode
    virtual bool Open(bool writable = false) { return false; }
    /// Closes the 'source'
    virtual bool Close() { return false; }
    /// Creates a new 'source' 
    /// Default mode is read only 
    /// If IsWritable and writable==true then opens in read/write mode
    virtual bool Create(bool writable = false) { return false; }
    /// Destroys the 'source'
    virtual bool Destroy() { return false; }
    ///====================================================================


    ///====================================================================
    // READ METHODS
    ///====================================================================


    ///====================================================================
    /// Returns the number of children of the Node *WITHOUT LOADING THEM*
    /// REM : The Tree itself is a Node and asking for its number of 
    ///       children returns the number of children of level 1.
    virtual unsigned int GetNumberOfChildren(tree::Node* n) { return 0; }
    ///====================================================================

    ///====================================================================
    /// Recursively loads the children of node 'parent' until maxlevel 
    /// is reached.
    /// If parent == NULL or parent == tree then starts with the 'children' of 
    /// the tree itself.
    /// Returns the total number of children loaded.
    virtual int LoadChildren(tree::Node* parent, int maxlevel) 
    { return 0; }
    ///====================================================================

    ///====================================================================
    /// Unloads the Node and its descendants
    /// WITHOUT altering the source, e.g. the database
    virtual void UnLoad(tree::Node* n) { return; }
    ///====================================================================


    ///====================================================================
    /// WRITE METHODS : WORK ONLY IN WRITE MODE
    ///====================================================================
    typedef tree::Node::AttributeMapType AttributeMapType;
   /// Adds a branch in the tree with the attributes provided
    /// returns the Level in the tree where the branch was connected 
    /// (-1 for error, 0 for top level, etc. ) 
    /// Of course the branch is loaded on exit
    virtual int AddBranch( const AttributeMapType& ) { return -1; }
    /// Removes the node and its descendants 
    bool Remove(tree::Node*)  { return false; }
    ///====================================================================


  private:
    /// The handled tree
    tree::Tree mTree;

  };
  // EO class TreeHandler
  //=======================================================================


} // EO namespace creaImageIO

// EOF
#endif