类型：转载 责任编辑：asp.net 日期：2007/05/23
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function TManager.GetSalaries: Integer;
var
i, sum, n: Integer;
nam: string;
begin
sum:=GetSalary;
for i:=0 to children.Count-1 do
begin
//调试中观察以下的nam值可以了解合成模式是如何递归遍历对象的。
// nam:=TOrganizedMan(children.Items[i]).getName;
n:=TOrganizedMan(children.Items[i]).getSalaries;
sum:=sum+n;
end;
result:=sum;
end;
TOrganizedMan(children.Items[i])这是什么用法？我对delphi语法不是很熟，只是为学模式才看的。
下面是整个源码：
{
_______________________________________________________
*******************************************************
《Delphi模式编程》
(Thinking in patterns with Delphi)
示例程序
程序名称：Firm
Ver：2.0
作者： 刘艺
（http://www.liu-yi.net）
版权所有 侵权必究 All rights reserved worldwide
警告：本程序供读者学习使用，未经同意不得作商业用途。
最后更新时间：2004－06－29
_______________________________________________________
*******************************************************
}
unit composite_Org;
interface
uses
SysUtils, Windows, Messages, Classes, Graphics, Controls,
Forms, Dialogs,Contnrs,ComCtrls;
type
TOrganizedMan = class (TObject)
public
constructor create(name:string;salary:integer); virtual; abstract;
procedure Add(OrganizedMan:TOrganizedMan); virtual; abstract;
procedure FreeChildren; virtual; abstract;
function GetChild(index:Integer): TOrganizedMan; virtual; abstract;
function getName: string; virtual; abstract;
function GetSalaries: Integer; virtual; abstract;
function getSalary: Integer; virtual; abstract;
procedure Remove(OrganizedMan:TOrganizedMan); virtual; abstract;
procedure SetItems(items:TStrings;level:integer); virtual; abstract;
end;
TEmployee = class (TOrganizedMan)
private
FName: string;
FSalary: Integer;
function GetSalary: Integer; override;
public
constructor Create(name:string;salary:integer); override;
procedure Add(OrganizedMan:TOrganizedMan); override;
procedure FreeChildren; override;
function GetChild(Index:Integer): TOrganizedMan; override;
function getName: string; override;
function GetSalaries: Integer; override;
procedure Remove(OrganizedMan:TOrganizedMan); override;
procedure SetItems(items:TStrings;level:integer); overload; override;
end;
TManager = class (TOrganizedMan)
private
children: TObjectList;
FName: string;
FSalary: Integer;
function GetSalary: Integer; override;
public
constructor Create(name:string;salary:integer); override;
procedure Add(OrganizedMan:TOrganizedMan); override;
procedure FreeChildren; override;
function GetChild(Index:Integer): TOrganizedMan; override;
function getName: string; override;
function GetSalaries: Integer; override;
procedure Remove(OrganizedMan:TOrganizedMan); override;
procedure SetItems(items:TStrings;level:integer); override;
end;
implementation
{
********************************** TEmployee ***********************************
}
constructor TEmployee.Create(name:string;salary:integer);
begin
FName:=name;
FSalary:=salary;
end;
procedure TEmployee.Add(OrganizedMan:TOrganizedMan);
begin
raise Exception.CreateFmt(%s类实例是叶节点对象,无法为其增加子节点对象！,
[ClassName]);
end;
procedure TEmployee.FreeChildren;
var
a:string;
begin
if self<>nil then
begin
{ 演示销毁的对象 }
a:=销毁的对象:+getName;
application.MessageBox(PCHAR(a),提示,0);
freeandnil(self);
end;
end;
function TEmployee.GetChild(Index:Integer): TOrganizedMan;
begin
result:=nil;
end;
function TEmployee.getName: string;
begin
result:=FName;
end;
function TEmployee.GetSalaries: Integer;
begin
result:=FSalary;
end;
function TEmployee.GetSalary: Integer;
begin
result:=FSalary;
end;
procedure TEmployee.Remove(OrganizedMan:TOrganizedMan);
begin
raise Exception.CreateFmt(%s类实例是叶节点对象,无法为其删除子节点对象！,
[ClassName]);
end;
procedure TEmployee.SetItems(items:TStrings;level:integer);
var
s: string;
i: Integer;
begin
for i:=1 to level do s:=s+ ;
s:=s+FName;
items.AddObject(s,self);
end;
{
*********************************** TManager ***********************************
}
constructor TManager.Create(name:string;salary:integer);
begin
children:=TObjectList.Create;
FName:=name;
FSalary:=salary;
end;
procedure TManager.Add(OrganizedMan:TOrganizedMan);
begin
children.Add(OrganizedMan);
end;
procedure TManager.FreeChildren;
var
i: Integer;
a: string;
obj: TOrganizedMan;
begin
if self<>nil then
begin
for i:=children.Count-1 downto 0 do
begin
obj:=TOrganizedMan(children.Items[i]);
obj.FreeChildren;
end;
{ 演示销毁的对象 }
a:=销毁的对象:+getName;
application.MessageBox(PCHAR(a),提示,0);
freeandnil(self);
end;
end;
function TManager.GetChild(Index:Integer): TOrganizedMan;
begin
result:=TOrganizedMan(children.Items[Index]);
end;
function TManager.getName: string;
begin
result:=FName;
end;
function TManager.GetSalaries: Integer;
var
i, sum, n: Integer;
nam: string;
begin
sum:=GetSalary;
for i:=0 to children.Count-1 do
begin
//调试中观察以下的nam值可以了解合成模式是如何递归遍历对象的。
// nam:=TOrganizedMan(children.Items[i]).getName;
n:=TOrganizedMan(children.Items[i]).getSalaries;
sum:=sum+n;
end;
result:=sum;
end;
function TManager.GetSalary: Integer;
begin
result:=FSalary;
end;
procedure TManager.Remove(OrganizedMan:TOrganizedMan);
begin
children.Remove(OrganizedMan);
end;
procedure TManager.SetItems(items:TStrings;level:integer);
var
s: string;
i: Integer;
curItems: TStringList;
begin
for i:=1 to level do s:=s+ ;
s:=s+++FName;
items.AddObject(s,self);
for i:=0 to children.Count-1 do
begin
TOrganizedMan(children.Items[i]).SetItems(items,level+1)
end;
end;
end.
网友回答：
就是强制转化。它是一个树形结构，每个子节点本身又是一个相同类型的类，如此可以递归调用。使用TObjectList列表来保存其子节点，子节点的类型指定为TOrganizedMan，使用时再强制转化一次。