unit com.sunset.app.tracer;

interface

uses StrUtils,classes,SysUtils;

type

//==============================================================================
// 接口声明
//==============================================================================

//跟踪信息的接口
ITraceInfo = interface
function ToString: string;
end;
//输出目标的接口
IOutput = interface
procedure Write(const aInfo: ITraceInfo); //写入跟踪信息
end;

//==============================================================================
// 跟踪信息类 ,实现 ITraceInfo
//==============================================================================

//string形式的跟踪记录
TStringTI = class(TInterfacedObject, ITraceInfo)
private
FData: string;
public
constructor Create(data: string);
function ToString: string;
end;

//==============================================================================
// 跟踪信息输出类,实现 IOutput
//==============================================================================

TFileLog = class(TInterfacedObject, IOutput)
private
FLogFile: string;
public
constructor Create(const FileName: string);
procedure Write(const aInfo: ITraceInfo); //写入跟踪信息
end;

TProcStr = procedure(const value:string) of Object;
TDatabaseLog = class(TInterfacedObject, IOutput)
private
FWriteProc :TProcStr;
public
constructor Create(WriteProc: TProcStr);
procedure Write(const aInfo: ITraceInfo); //写入跟踪信息
end;

//==============================================================================
// 跟踪工具
//==============================================================================

{ TTracer }
//用来进行记录跟踪日志的类
TTracer = class(TObject)
private
FOutput: IOutput; //输出目标
procedure SetOutput(const Value: IOutput);
public
constructor Create; overload;
constructor Create(aOutput: IOutput); overload;
destructor Destroy; override;
property Output: IOutput read FOutput write SetOutput;
procedure Write(const aInfo: ITraceInfo); //写入跟踪信息
end;

implementation

{ TTracer }

constructor TTracer.Create;
begin

end;

constructor TTracer.Create(aOutput: IOutput);
begin
FOutput := aOutput;
end;

destructor TTracer.Destroy;
begin
if FOutput <> nil then FOutput := nil;
inherited;
end;

procedure TTracer.SetOutput(const Value: IOutput);
begin
FOutput := Value;
end;

procedure TTracer.Write(const aInfo: ITraceInfo);
begin
if FOutput = nil then raise Exception.CreateFmt('没有创建输出目标%s!!!', []);
FOutput.Write(aInfo);
end;

{ TStringTI }

constructor TStringTI.Create(data: string);
begin
FData := Data;
end;

function TStringTI.ToString: string;
begin
Result := FData;
end;

{ TStringLog }

constructor TFileLog.Create(const FileName: string);
begin
FLogFile := FileName;
end;

procedure TFileLog.Write(const aInfo: ITraceInfo);
begin
if not FileExists(FLogFile) then FileClose(FileCreate(FLogFile));
with TStringList.Create do
begin
try
LoadFromFile(FLogFile);
Add(aInfo.ToString);
SaveToFile(FLogFile);
finally
Free;
end;
end;
end;

{ TDatabaseLog }

constructor TDatabaseLog.Create(WriteProc: TProcStr);
begin
FWriteProc := WriteProc;
if not Assigned(FWriteProc) then raise Exception.CreateFmt('没有传入正确的写入跟踪方法%s!!!', []);
end;

procedure TDatabaseLog.Write(const aInfo: ITraceInfo);
begin
FWriteProc(aInfo.ToString);
end;

end.

===================测试代码==========================
{******************************************************************************}
{ }
{ 测试名称： }
{ 作 者： }
{ 版 本： }
{ 说 明： }
{ 备 注： }
{ }
{******************************************************************************}

unit test.com.sunset.app.tracer;

interface

uses
Windows, SysUtils, Classes, TestFramework, TestExtensions,
com.sunset.app.tracer;

type
TTest = class(TTestCase)
protected
procedure SetUp; override;
procedure TearDown; override;

published
procedure TestTracer;
end;

implementation

procedure TTest.Setup;
begin

end;

procedure TTest.TearDown;
begin

end;

procedure TTest.TestTracer;
var
tracer:TTracer;
aInfo:ITraceInfo;
const
testData ='adfadfdasf';
testFile ='d:\2.txt';
begin
aInfo := TStringTI.Create(testData);
Tracer := TTracer.Create(TFileLog.Create(testfile));
Tracer.Write(aInfo);
Tracer.Free;
aInfo := nil;
with TStringList.Create do
begin
LoadFromFile(testfile);
Check(Strings[Count -1] = testData);
Free;
end;
end;

initialization
TestFramework.RegisterTest(TTest.Suite);

end.