1 // Created on: 2017-06-16
2 // Created by: Natalia ERMOLAEVA
3 // Copyright (c) 2017 OPEN CASCADE SAS
5 // This file is part of Open CASCADE Technology software library.
7 // This library is free software; you can redistribute it and/or modify it under
8 // the terms of the GNU Lesser General Public License version 2.1 as published
9 // by the Free Software Foundation, with special exception defined in the file
10 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
11 // distribution for complete text of the license and disclaimer of any warranty.
13 // Alternatively, this file may be used under the terms of Open CASCADE
14 // commercial license or contractual agreement.
16 #ifndef TreeModel_ItemBase_H
17 #define TreeModel_ItemBase_H
19 #include <Standard.hxx>
20 #include <Standard_Macro.hxx>
21 #include <inspector/TreeModel_ItemRole.hxx>
24 #pragma warning(disable : 4127) // conditional expression is constant
26 #include <QExplicitlySharedDataPointer>
29 #include <QModelIndex>
32 #include <QSharedData>
35 class TreeModel_ItemBase;
37 typedef QExplicitlySharedDataPointer<TreeModel_ItemBase> TreeModel_ItemBasePtr;
39 //! \class TreeModel_ItemBase
40 //! \brief Declaration of an abstract interface of model item.
42 //! The TreeModel_ItemBase class defines the standard interface that model items must use
43 //! to be able to provide the model information in the tree view architecture.
44 //! It is not supposed to be instantiated directly. Instead, you should subclass it to
47 //! The goal of the item is to be an data container of a custom model, based on the
48 //! QAbstractItemModel. It provides the items architecture in order to realize the model
49 //! functionality to find a parent model index by a child index and vise versa.
51 //! The item should be created by the model and is saved in the internal pointer of the
52 //! QModelIndex. Only model knows when the index is removed/created. By this cause,
53 //! the item is wrapped in the QExplicitlySharedDataPointer. It is a counter on the pointer
54 //! and if there is no index that refers to the item, it is removed automatically. So,
55 //! there is no necessity to remove the item manually.
57 //! The item knows a pointer to the parent item and its position into.
58 //! Some methods of the item should be realized to fill the item content.
59 //! These are: the children count, a child creation and a child data.
61 //! The best way of the item using is to request the content of the item from some
62 //! information object without the caching it. But it can be very expensive realisation,
63 //! because method data, for example, is called by the viewer repaint, in other words,
66 //! It is possible to cache some information in the item. Do not give it throught the item
67 //! constructor. Realize method Init() to save the values in the item internal fields.
68 //! If the information model is changed, call Reset() for this item, or the item's parent.
69 //! It leads the item to non initialized state and by the next get of the item content,
70 //! call Init() method to fulfill the item content again.
71 class TreeModel_ItemBase : public QSharedData
76 virtual ~TreeModel_ItemBase() {}
78 //! Gets whether the item is already initialized.The initialized state is thrown down
79 //! by the reset method and get back after the method Init().
80 //! \return if the item is initialized
81 bool IsInitialized() const { return m_bInitialized; }
83 //! Sets the item internal initialized state to the true. If the item has internal values,
84 //! there should be initialized here.
85 virtual void Init() { m_bInitialized = true; }
87 //! Resets the item and the child items content. Sets the initialized state to false.
88 //! If the item has internal values, there should be reseted here.
89 Standard_EXPORT virtual void Reset();
91 //! Gets the parent of the item, or TreeModel_ItemBasePtr() if it has no parent.
92 //! \return pointer to the item
93 TreeModel_ItemBasePtr Parent() const { return m_pParent; };
95 //! Gets the row of the item in the parent
96 //! \return the row position
97 int Row() const { return m_iRow; }
99 //! Gets the column of the item in the parent
100 //! \return the column position
101 int Column() const { return m_iColumn; }
103 //! Gets a child tree item in the given position. Find an item in the children hash.
104 //! Creates a new child item, if there is no a cached item in the given position and
105 //! if the flag about the creation is true.
106 //! \param theRow the row of the child item
107 //! \param theColumn the column of the child item
108 //! \param isToCreate the flag whether the item should be created if it is not created yet
109 //! \return the child item or TreeModel_ItemBasePtr() if it does not exist
110 Standard_EXPORT TreeModel_ItemBasePtr Child (int theRow, int theColumn, const bool isToCreate = true);
112 //! Returns the data stored under the given role for the current item
113 //! \param theIndex the item model index
114 //! \param theRole the item model role
115 virtual QVariant data (const QModelIndex& theIndex, int theRole = Qt::DisplayRole) const
116 { (void)theIndex; return cachedValue(theRole); }
118 //! Returns number of rows where the children are
119 //! \return the row count
120 int rowCount() const { return cachedValue(TreeModel_ItemRole_RowCountRole).toInt(); }
124 //! \param theParent the parent item
125 //! \param theRow the item row positition in the parent item
126 //! \param theColumn the item column positition in the parent item
127 Standard_EXPORT TreeModel_ItemBase (TreeModel_ItemBasePtr theParent, const int theRow, const int theColumn);
129 //! Creates a child item in the given position.
130 //! \param theRow the child row position
131 //! \param theColumn the child column position
132 //! \return the created item
133 virtual TreeModel_ItemBasePtr createChild (int theRow, int theColumn) = 0;
135 //! Wraps the currrent item by shared pointer
136 //! \return the shared pointer to the current item
137 Standard_EXPORT const TreeModel_ItemBasePtr currentItem();
139 //! Returns the cached value for the role. Init the value if it is requested the first time
140 //! By default, it calls initRowCount(TreeModel_ItemRole_RowCountRole) or initValue for the item role
141 //! \param theItemRole a value role
142 //! \return the value
143 Standard_EXPORT QVariant cachedValue (const int theItemRole) const;
145 //! \return number of children. It should be reimplemented in child
146 virtual int initRowCount() const = 0;
148 //! Return data value for the role. It should be reimplemented in child
149 //! \param theItemRole a value role
150 //! \return the value
151 virtual QVariant initValue (const int theItemRole) const = 0;
155 typedef QHash< QPair<int, int>, TreeModel_ItemBasePtr > PositionToItemHash;
156 PositionToItemHash m_ChildItems; //!< the hash of item children
158 QMap<int, QVariant> mycachedValues; //!< cached values, should be cleared by reset
159 TreeModel_ItemBasePtr m_pParent; //!< the parent item
160 int m_iRow; //!< the item row position in the parent item
161 int m_iColumn; //!< the item column position in the parent item
162 bool m_bInitialized; //!< the state whether the item content is already initialized
165 //! Returns an explicitly shared pointer to the pointer held by other, using a
166 //! dynamic cast to type X to obtain an internal pointer of the appropriate type.
167 //! If the dynamic_cast fails, the object returned will be null.
168 //! Example of using:
169 //! TreeModel_ItemBase* aParent;
170 //! TreeModel_CustomItemPtr aParentItem = itemDynamicCast<TreeModel_CustomItem>(aParent);
171 //! \param theItem a source item
172 //! \return a converted item
173 template <class X, class T> QExplicitlySharedDataPointer<X> itemDynamicCast (const QExplicitlySharedDataPointer<T>& theItem)
175 X* ptr = dynamic_cast<X*> (theItem.data());
177 QExplicitlySharedDataPointer<X> result;