Design Mode-Command pattern undo

Command pattern undo

Address: http://blog.csdn.net/caroline_wendy

Test command mode:Http://blog.csdn.net/caroline_wendy/article/details/31379977

Command modeCan be used for runningUndo operation.

Detailed method:

1. object classes are requiredSave status, Such as level.

package command;public class CeilingFan {String location = "";int level;public static final int HIGH = 3;public static final int MEDIUM = 2;public static final int LOW = 1;public static final int OFF = 0; public CeilingFan(String location) {this.location = location;}  public void high() {// turns the ceiling fan on to highlevel = HIGH;System.out.println(location + " ceiling fan is on high"); } public void medium() {// turns the ceiling fan on to mediumlevel = MEDIUM;System.out.println(location + " ceiling fan is on medium");}public void low() {// turns the ceiling fan on to lowlevel = LOW;System.out.println(location + " ceiling fan is on low");} public void off() {// turns the ceiling fan offlevel = OFF;System.out.println(location + " ceiling fan is off");} public int getSpeed() {return level;}}

2. command interface, including undo (UNDO) operation, that is, the detailed undo action is inferred based on the number of states of the input object.

/*** @ Time June 9, 2014 */package command;/*** @ author C. l. wang **/public interface command {public void execute (); Public void undo (); // undo}

3. Concrete command)Class must be implemented and abolished, based on Different statusesTo run different undo operations.

/*** @ Time June 16, 2014 */package command;/*** @ author C. l. wang **/public class ceilingfanhighcommand implements command {ceilingfan; int prevspeed; Public ceilingfanhighcommand (ceilingfan) {This. ceilingfan = ceilingfan;}/* (non-javadoc) * @ see command. command # execute () */@ overridepublic void execute () {// todo auto-generated method stubprevspeed = ceilingfan. getspeed (); ceilingfan. high ();}/* (non-javadoc) * @ see command. command # undo () */@ overridepublic void undo () {// todo auto-generated method stubif (prevspeed = ceilingfan. high) {ceilingfan. high ();} else if (prevspeed = ceilingfan. medium) {ceilingfan. medium ();} else if (prevspeed = ceilingfan. low) {ceilingfan. low ();} else if (prevspeed = ceilingfan. off) {ceilingfan. off () ;}} package command; public class ceilingfanmediumcommand implements command {ceilingfan; int prevspeed; Public ceilingfanmediumcommand (ceilingfan) {This. ceilingfan = ceilingfan;} public void execute () {prevspeed = ceilingfan. getspeed (); ceilingfan. medium ();} public void undo () {If (prevspeed = ceilingfan. high) {ceilingfan. high ();} else if (prevspeed = ceilingfan. medium) {ceilingfan. medium ();} else if (prevspeed = ceilingfan. low) {ceilingfan. low ();} else if (prevspeed = ceilingfan. off) {ceilingfan. off () ;}} package command; public class ceilingfanlowcommand implements command {ceilingfan; int prevspeed; Public ceilingfanlowcommand (ceilingfan) {This. ceilingfan = ceilingfan;} public void execute () {prevspeed = ceilingfan. getspeed (); ceilingfan. low ();} public void undo () {If (prevspeed = ceilingfan. high) {ceilingfan. high ();} else if (prevspeed = ceilingfan. medium) {ceilingfan. medium ();} else if (prevspeed = ceilingfan. low) {ceilingfan. low ();} else if (prevspeed = ceilingfan. off) {ceilingfan. off () ;}} package command; public class ceilingfanoffcommand implements command {ceilingfan; int prevspeed; Public ceilingfanoffcommand (ceilingfan) {This. ceilingfan = ceilingfan;} public void execute () {prevspeed = ceilingfan. getspeed (); ceilingfan. off ();} public void undo () {If (prevspeed = ceilingfan. high) {ceilingfan. high ();} else if (prevspeed = ceilingfan. medium) {ceilingfan. medium ();} else if (prevspeed = ceilingfan. low) {ceilingfan. low ();} else if (prevspeed = ceilingfan. off) {ceilingfan. off ();}}}

4. Receiver classImplementation Undo)Operation, that is, when a command is called, Reserved command, Run Undo operation, Call Reserved commands.

/*** @ Time June 16, 2014 */package command;/*** @ author C. l. wang **/public class remotecontrol {Command [] oncommands; // enable command [] offcommands; // disable command undocommand; // cancel public remotecontrol () {oncommands = new command [7]; offcommands = new command [7]; command nocommand = new nocommand (); For (INT I = 0; I <7; ++ I) {// initialize oncommands [I] = nocommand; offcommands [I] = nocommand;} undocommand = nocommand;} public void setcommand (INT slot, command oncommand, command offcommand) {This. oncommands [Slot] = oncommand; this. offcommands [Slot] = offcommand;} public void onbuttonwaspushed (INT slot) {// reset cute (); undocommand = oncommands [Slot];} public void offbuttonwaspushed (INT slot) {// close buttonoffcommands[slot0000.exe cute (); undocommand = offcommands [Slot];} public void undobuttonwaspushed () {undocommand. undo ();} Public String tostring () {stringbuffer = new stringbuffer (); stringbuffer. append ("\ n ------ Remote Control ------ \ n"); For (INT I = 0; I <oncommands. length; ++ I) {stringbuffer. append ("[slot" + I + "]" + oncommands [I]. getclass (). getname () + "" + offcommands [I]. getclass (). getname () + "\ n");} return stringbuffer. tostring ();}}

5.Trial Class, Call different commands, save different statuses, and run the Undo operation.

/*** @ Time June 16, 2014 */package command; import javax. crypto. spec. ivparameterspec;/*** @ author C. l. wang **/public class remoteloader {/*** @ Param ARGs */public static void main (string [] ARGs) {// todo auto-generated method stubremotecontrol remotecontrol = new remotecontrol (); light livingroomlight = new light ("living room"); light kitchenlight = new light ("Kitchen "); ceilingfan = new ceilingfan ("living room"); garagedoor = new garagedoor (""); stereo = new stereo ("living room "); lightoncommand completion = new lightoncommand (livingroomlight); lightoffcommand completion = new lightoffcommand (livingroomlight); lightoncommand kitchenlighton = new lightoncommand (kitchenlight); completion = new completion (kitchenlight ); ceilingfanhighcommand ceilingfanhigh = new ceilingfanhighcommand (ceilingfan); Response response = new response (ceilingfan); Response ceilingfanoff = new response (ceilingfan); Response garagedooron = new response (garagedoor ); export garagedooroff = new external (garagedoor); stereoonwithcdcommand stereoonwithcd = new stereoonwithcdcommand (STEREO); stereooffcommand = new stereooffcommand (STEREO); remotecontrol. setcommand (0, livingroomlighton, livingroomlightoff); // set this remote control remotecontrol. setcommand (1, kitchenlighton, kitchenlightoff); remotecontrol. setcommand (2, ceilingfanhigh, ceilingfanoff); remotecontrol. setcommand (3, ceilingfanmedium, ceilingfanoff); remotecontrol. setcommand (4, stereoonwithcd, stereooffcommand); remotecontrol. onbuttonwaspushed (2); // rapid remotecontrol. offbuttonwaspushed (2); // disable quick system. out. println (remotecontrol); remotecontrol. undobuttonwaspushed (); // return to quick system. out. println (); remotecontrol. onbuttonwaspushed (3); // Medium Speed System. out. println (remotecontrol); remotecontrol. undobuttonwaspushed (); // fast }}

6. Output:

Living Room ceiling fan is on highLiving Room ceiling fan is off------ Remote Control ------[slot 0] command.LightOnCommand    command.LightOffCommand[slot 1] command.LightOnCommand    command.LightOffCommand[slot 2] command.CeilingFanHighCommand    command.CeilingFanOffCommand[slot 3] command.CeilingFanMediumCommand    command.CeilingFanOffCommand[slot 4] command.StereoOnWithCDCommand    command.StereoOffCommand[slot 5] command.NoCommand    command.NoCommand[slot 6] command.NoCommand    command.NoCommandLiving Room ceiling fan is on highLiving Room ceiling fan is on medium------ Remote Control ------[slot 0] command.LightOnCommand    command.LightOffCommand[slot 1] command.LightOnCommand    command.LightOffCommand[slot 2] command.CeilingFanHighCommand    command.CeilingFanOffCommand[slot 3] command.CeilingFanMediumCommand    command.CeilingFanOffCommand[slot 4] command.StereoOnWithCDCommand    command.StereoOffCommand[slot 5] command.NoCommand    command.NoCommand[slot 6] command.NoCommand    command.NoCommandLiving Room ceiling fan is on high

Other code downloads: http://download.csdn.net/detail/u012515223/7507147

Design Mode-Command pattern undo