Src/DasherCore/NodeManager.h

   1 // NodeManager.h
   2 //
   3 // Copyright (c) 2007 The Dasher Team
   4 //
   5 // This file is part of Dasher.
   6 //
   7 // Dasher is free software; you can redistribute it and/or modify
   8 // it under the terms of the GNU General Public License as published by
   9 // the Free Software Foundation; either version 2 of the License, or
  10 // (at your option) any later version.
  11 //
  12 // Dasher is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with Dasher; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20
  21 #ifndef __nodemanager_h__
  22 #define __nodemanager_h__
  23
  24 #include "DasherTypes.h"
  25
  26 namespace Dasher {
  27   class CDasherNode; // Forward declaration
  28
  29   /// \ingroup Model
  30   /// @{
  31
  32   /// The node management process assigns an instance of a subclass of
  33   /// CNodeManager to each Dasher node in the tree. Typically a
  34   /// contiguous subtree will be represented by a single CNodeManager,
  35   /// but multiple subtrees will often share the same
  36   /// CNodeManager. CNodeManagers implement reference counting to
  37   /// ensure that they are deleted when no longer required.
  38   ///
  39   /// This mechanism allows broad classes of nodes to be defined with
  40   /// their own behaviour, for example, regular 'alphabet' nodes are
  41   /// managed by an instance of CAlphabetManager. CNodeManagers also
  42   /// currently exist for control nodes, and subtrees representing the
  43   /// conversion process in certain languages.
  44   ///
  45   /// The node manager is responsible for the following aspects of the
  46   /// lifespan of a node:
  47   ///
  48   /// 1. Construction of the root node for the subtree.
  49   ///
  50   /// 2. Population of the children of a node, and regeneration of the
  51   /// parent node where necessary
  52   ///
  53   /// 3. Behaviour when the node enters or leaves the crosshair.
  54   ///
  55   /// 4. Behaviour when the node's flag status changes.
  56   ///
  57   /// 5. Deletion of manager-specific data when the node is deleted.
  58   ///
  59   /// The CDasherNode class provides a 'user data' pointer which is
  60   /// intended for the node manager to use as a store for any
  61   /// manager-specific status information.
  62   ///
  63   class CNodeManager {
  64   public:
  65     CNodeManager(int iID) {
  66       m_iID = iID;
  67     };
  68
  69     virtual int GetID() {
  70       return m_iID;
  71     };
  72
  73     /// Increment reference count
  74     ///
  75     virtual void Ref() = 0;
  76
  77     /// Decrement reference count
  78     ///
  79     virtual void Unref() = 0;
  80
  81     ///
  82     /// Get a new root node owned by this manager
  83     ///
  84
  85
  86     virtual CDasherNode *GetRoot(CDasherNode *pParent, int iLower, int iUpper, void *pUserData) = 0;
  87
  88     ///
  89     /// Provide children for the supplied node
  90     ///
  91
  92     virtual void PopulateChildren( CDasherNode *pNode ) = 0;
  93
  94     ///
  95     /// Delete any storage alocated for this node
  96     ///
  97
  98     virtual void ClearNode( CDasherNode *pNode ) = 0;
  99
 100     ///
 101     /// Called whenever a node belonging to this manager first
 102     /// moves under the crosshair
 103     ///
 104
 105     virtual void Output( CDasherNode *pNode, Dasher::VECTOR_SYMBOL_PROB* pAdded, int iNormalization) {};
 106     virtual void Undo( CDasherNode *pNode ) {};
 107
 108     virtual void Enter(CDasherNode *pNode) {};
 109     virtual void Leave(CDasherNode *pNode) {};
 110
 111     virtual CDasherNode *RebuildParent(CDasherNode *pNode, int iGeneration) {
 112       return 0;
 113     }
 114
 115     virtual void SetFlag(CDasherNode *pNode, int iFlag, bool bValue) {};
 116
 117     virtual void SetControlOffset(CDasherNode *pNode, int iOffset) {};
 118
 119   private:
 120     int m_iID;
 121   };
 122   /// @}
 123 }
 124
 125 #endif