Command mode

Recently, I learned a fans, so I want to write an article about the model. This article is an example of << Java and the model >> (阎 宏), I change it into Delphi. I wrote something I hope everyone can understand.

This example is still better understood, so only the code is given.

UNIT PATTERN;

Interface

Uses dialogs;

TYPE TAUDIOPLAYER = Class;

TCOMMAND = Class Public Procedure EXECUTE ;VIRTUAL;

TPLAYCOMMAND = Class (TCOMMAND) Private Audioplayer: Taudioplayer; Public Procedure EXECUTE; OVERRIDE; Procedure PlayCommand (ap: taudioplayer);

TSTOPCOMMAND = Class (TCOMMAND) Private Audioplayer: Taudioplayer; Public Procedure EXECUTE; OVERRIDE; Procedure Stopcomman (ap: taudioPlayer);

TREWINDCOMMAND = Class (TCOMMAND) Private Audioplayer: TaudioPlayer; Public Procedure EXECUTE; OVERRIDE; Procedure RewindCommand (AP: Taudioplayer);

TKeyPad = class private PlayCommand: TCommand; StopCommand: TCommand; RewindCommand: TCommand; public constructor Create (PlayC, StopC, RewindC: TCommand); virtual; procedure play (); procedure stop (); procedure rewind (); end;

TAUDIOPLAYER = Class Public Procedure Play (); Procedure Stop (); Procedure Rew India ();

Tclient = Class Private Keypad: TKEYPAD; Audioplayer: Taudioplayer; PUBLIC Constructor Create (); Procedure Test ();

IMPLEMENTATION

{TKEYPAD}

Constructor tkeypad.create (Playc, Stopc, Rewindc: TCommand); Begin PlayCommand: = Playc; StopCommand: = Stopc; RewindCommand: = REWINDC; END;

Procedure tkeypad.play; begin playcommand.execute;

Procedure tkeypad.rew; begin rebindcommand.execute;

Procedure tkeypad.stop; begin stopcommand.execute;

{Taudioplayer}

Procedure taudioplayer.play; begin showmessage ('play'); end; procedure taudioplayer.rewding; begin showMessage ('rebind');

Procedure taudioplayer.stop; begin showmessage ('stop'); end;

{TPLAYCOMMAND}

Procedure tplayCommand.execute; begin inherited; audioplayer.play ();

Procedure tplaycommand.playcommand (ap: taudioplayer); begin self.audioPlayer: = ap;

{TREWINDCOMMAND}

Procedure TrewindCommand.execute; begin inherited; audioplayer.rew;

Procedure Trewindcommand.rewindcommand (ap: taudioplayer); begin audioplayer: = ap;

{TStopCommand}

Procedure tstopCommand.execute; begin inherited; audioplayer.stop;

Procedure tstopcommand.stopcomman (ap: taudioplayer); begin AudioPlayer: = ap;

{Tclient}

Constructor tclient.create; begin audioplayer: = taudioPlayer.create ();

procedure TClient.test; var PlayCommand: TCommand; StopCommand: TCommand; RewindCommand: TCommand; begin PlayCommand: = TPlayCommand.Create; StopCommand: = TStopCommand.Create; RewindCommand: = TRewindCommand.Create; KeyPad: = TKeyPad.Create (PlayCommand, StopCommand , ReWindCommand; keypad.stop; keypad.play; keys;

End.