{
* UOverviewTreeBuilder.pas
*
* Implements a set of classes that populate the overview treeview with a list
* of snippets. Each class groups the snippets in different ways.
*
* $Rev$
* $Date$
*
* ***** BEGIN LICENSE BLOCK *****
*
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The Original Code is UOverviewTreeBuilder.pas
*
* The Initial Developer of the Original Code is Peter Johnson
* (http://www.delphidabbler.com/).
*
* Portions created by the Initial Developer are Copyright (C) 2009-2011 Peter
* Johnson. All Rights Reserved.
*
* Contributor(s)
* NONE
*
* ***** END LICENSE BLOCK *****
}
unit UOverviewTreeBuilder;
interface
uses
// Delphu
ComCtrls,
// Project
DB.USnippet, UGroups, UView, UViewItemTreeNode;
type
{
TOverviewTreeBuilder:
Abstract base class for classes that populate the overview treeview with a
list of snippets. Each subclass groups the snippets in different ways.
}
TOverviewTreeBuilder = class abstract(TObject)
strict private
var
fTreeView: TTreeView; // Value of TreeView property
fSnippetList: TSnippetList; // Value of SnippetList property
strict protected
property TreeView: TTreeView read fTreeView;
{Reference to treeview populated by class}
property SnippetList: TSnippetList read fSnippetList;
{List of snippets to be displayed in treeview}
function AddViewItemNode(const ParentNode: TViewItemTreeNode;
ViewItem: IView): TViewItemTreeNode;
{Adds a new node to the tree view that represents a view item.
@param ParentNode [in] Node that is parent of new node.
@param ViewItem [in] View item for which we are adding node.
@return New tree node.
}
function CreateGrouping: TGrouping; virtual; abstract;
{Creates a grouping object of the required type.
@return Required grouping object.
}
function CreateViewItemForGroup(const Group: TGroupItem): IView;
virtual; abstract;
{Creates a view item of a type that matches the type of a group item.
@param Group [in] Group item for which view item is required.
@return Required view item object.
}
public
constructor Create(const TV: TTreeView; const SnippetList: TSnippetList);
{Class constructor. Sets up object to populate a treeview with a list of
snippets.
@param TV [in] Treeview control to be populated.
@param SnippetList [in] List of snippets to be added to TV.
}
procedure Build;
{Populates the treeview.
}
end;
{
TOverviewTreeBuilderClass:
Class reference for TOverviewTreeBuilder sub-classes.
}
TOverviewTreeBuilderClass = class of TOverviewTreeBuilder;
{
TOverviewCategorisedTreeBuilder:
Class that populates the overview treeview with a list of snippets grouped
by category.
}
TOverviewCategorisedTreeBuilder = class sealed(TOverviewTreeBuilder)
strict protected
function CreateGrouping: TGrouping; override;
{Creates a categorised grouping object.
@return Required grouping object.
}
function CreateViewItemForGroup(const Group: TGroupItem): IView;
override;
{Creates a category view item from group item.
@param Group [in] Group item containing category data.
@return Required category view item for group.
}
end;
{
TOverviewAlphabeticTreeBuilder:
Class that populates the overview treeview with a list of snippets grouped
by initial letter of the snippet name.
}
TOverviewAlphabeticTreeBuilder = class sealed(TOverviewTreeBuilder)
strict protected
function CreateGrouping: TGrouping; override;
{Creates an alphabetic grouping object.
@return Required grouping object.
}
function CreateViewItemForGroup(const Group: TGroupItem): IView;
override;
{Creates an alpha view item from group item.
@param Group [in] Group item containing alpha data.
@return Required alpha view item for group.
}
end;
{
TOverviewSnipKindTreeBuilder:
Class that populates the overview treeview with a list of snippets grouped
by snippet kind.
}
TOverviewSnipKindTreeBuilder = class sealed(TOverviewTreeBuilder)
strict protected
function CreateGrouping: TGrouping; override;
{Creates a snippet kind grouping object.
@return Required grouping object.
}
function CreateViewItemForGroup(const Group: TGroupItem): IView;
override;
{Creates a snippet kind view item from group item.
@param Group [in] Group item containing snippet kind data.
@return Required snippet kind view item for group.
}
end;
implementation
{
NOTE:
Early version of this code, that were contained in the FrOverview unit used
to add a section head tree node for every category and then delete empty ones.
However, attempts to delete the first node from a tree causes an endless loop,
freezing the program. This could be a bug in the Delphi treeview component.
Therefore the code in this unit now builds or uses a list of snippets for
each section and does not create a section header node for sections that
contain no snippets.
}
{ TOverviewTreeBuilder }
function TOverviewTreeBuilder.AddViewItemNode(
const ParentNode: TViewItemTreeNode; ViewItem: IView): TViewItemTreeNode;
{Adds a new node to the tree view that represents a view item.
@param ParentNode [in] Node that is parent of new node.
@param ViewItem [in] View item for which we are adding node.
@return New tree node.
}
begin
Result := TreeView.Items.AddChild(ParentNode, ViewItem.Description)
as TViewItemTreeNode;
Result.ViewItem := ViewItem;
end;
procedure TOverviewTreeBuilder.Build;
{Populates the treeview.
}
var
Snippet: TSnippet; // each snippet in a list
ParentNode: TViewItemTreeNode; // each section node in tree
Grouping: TGrouping; // groups snippets
Group: TGroupItem; // each group of snippets
begin
// Create required grouping of snippets
Grouping := CreateGrouping;
try
// Create tree
for Group in Grouping do
begin
if not Group.IsEmpty then
begin
ParentNode := AddViewItemNode(nil, CreateViewItemForGroup(Group));
for Snippet in Group.SnippetList do
AddViewItemNode(
ParentNode, TViewItemFactory.CreateSnippetView(Snippet)
);
end;
end;
finally
Grouping.Free;
end;
end;
constructor TOverviewTreeBuilder.Create(const TV: TTreeView;
const SnippetList: TSnippetList);
{Class constructor. Sets up object to populate a treeview with a list of
snippets.
@param TV [in] Treeview control to be populated.
@param SnippetList [in] List of snippets to be added to TV.
}
begin
inherited Create;
fTreeView := TV;
fSnippetList := SnippetList;
end;
{ TOverviewCategorisedTreeBuilder }
function TOverviewCategorisedTreeBuilder.CreateGrouping: TGrouping;
{Creates a categorised grouping object.
@return Required grouping object.
}
begin
Result := TCategoryGrouping.Create(SnippetList);
end;
function TOverviewCategorisedTreeBuilder.CreateViewItemForGroup(
const Group: TGroupItem): IView;
{Creates a category view item from group item.
@param Group [in] Group item containing category data.
@return Required category view item for group.
}
begin
Result := TViewItemFactory.CreateCategoryView(
(Group as TCategoryGroupItem).Category
);
end;
{ TOverviewAlphabeticTreeBuilder }
function TOverviewAlphabeticTreeBuilder.CreateGrouping: TGrouping;
{Creates an alphabetic grouping object.
@return Required grouping object.
}
begin
Result := TAlphaGrouping.Create(SnippetList);
end;
function TOverviewAlphabeticTreeBuilder.CreateViewItemForGroup(
const Group: TGroupItem): IView;
{Creates an alpha view item from group item.
@param Group [in] Group item containing alpha data.
@return Required alpha view item for group.
}
begin
Result := TViewItemFactory.CreateInitialLetterView(
(Group as TAlphaGroupItem).Letter
);
end;
{ TOverviewSnipKindTreeBuilder }
function TOverviewSnipKindTreeBuilder.CreateGrouping: TGrouping;
{Creates a snippet kind grouping object.
@return Required grouping object.
}
begin
Result := TSnipKindGrouping.Create(SnippetList);
end;
function TOverviewSnipKindTreeBuilder.CreateViewItemForGroup(
const Group: TGroupItem): IView;
{Creates a snippet kind view item from group item.
@param Group [in] Group item containing snippet kind data.
@return Required snippet kind view item for group.
}
begin
Result := TViewItemFactory.CreateSnippetKindView(
(Group as TSnipKindGroupItem).SnipKindInfo
);
end;
end.
