{"id":1049,"date":"2024-05-22T14:50:51","date_gmt":"2024-05-22T06:50:51","guid":{"rendered":"http:\/\/www.spiceandwolf.com.cn\/?p=1049"},"modified":"2024-05-22T14:50:52","modified_gmt":"2024-05-22T06:50:52","slug":"design-pattern-command-pattern","status":"publish","type":"post","link":"http:\/\/www.spiceandwolf.com.cn\/index.php\/design-pattern-command-pattern\/","title":{"rendered":"\u8bbe\u8ba1\u6a21\u5f0f-\u547d\u4ee4\u6a21\u5f0f"},"content":{"rendered":"\n<p>\u547d\u4ee4\u6a21\u5f0f\u7684\u76ee\u7684\u662f\u628a\u8bf7\u6c42\u8c03\u7528\u5c01\u88c5\u8d77\u6765\u3002<\/p>\n\n\n\n<p>\u5047\u8bbe\u6211\u4eec\u9700\u8981\u7528\u4e00\u4e2a\u9065\u63a7\u5668\uff0c\u8fd9\u4e2a\u9065\u63a7\u5668\u6709\u4e03\u4e2a\u63d2\u69fd\uff0c\u6bcf\u4e00\u4e2a\u63d2\u69fd\u7531\u4e24\u4e2a\u6309\u94ae\u63a7\u5236\uff0c\u6211\u4eec\u9700\u8981\u901a\u8fc7\u6bcf\u4e2a\u63d2\u69fd\u7684\u4e24\u4e2a\u6309\u94ae\u63a7\u5236\u5404\u79cd\u5404\u6837\u7684\u8bbe\u5907\uff0c\u6211\u4eec\u9700\u8981\u5982\u4f55\u5b9e\u73b0\u529f\u80fd\uff0c\u5e76\u5c06\u8bf7\u6c42\u548c\u884c\u4e3a\u89e3\u8026\u3002<\/p>\n\n\n\n<p>\u8fd9\u662f\u8bbe\u8ba1\u65b9\u6848\u4e00\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public interface Command {\n    public void execute();\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Light {\n    public void on() {\n        System.out.println(\"ligth on\\n\");\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class LightOnCommand implements Command {\n    Light light;\n    public LightOnCommand(Light light) {\n        this.light = light;\n    }\n\n    @Override\n    public void execute() {\n        light.on();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class SimpleRemoteControl {\n    Command slot;\n\n    public SimpleRemoteControl() {}\n\n    public void setCommand(Command command) {\n        slot = command;\n    }\n\n    public void buttonWasPressed() {\n        slot.execute();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class RemoteControlTest {\n    public static void main(String&#91;] args) {\n        SimpleRemoteControl remoteControl = new SimpleRemoteControl();\n        Light light = new Light();\n        LightOnCommand lightOnCommand = new LightOnCommand(light);\n\n        remoteControl.setCommand(lightOnCommand);\n        remoteControl.buttonWasPressed();\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u547d\u4ee4\u6a21\u5f0f\u7684\u5b9a\u4e49\uff1a\u547d\u4ee4\u6a21\u5f0f\u5c06\u8bf7\u6c42\u5c01\u88c5\u6210\u5bf9\u8c61\uff0c\u4ee5\u4fbf\u4f7f\u7528\u4e0d\u540c\u7684\u8bf7\u6c42\u3001\u961f\u5217\u3001\u6216\u8005\u65e5\u5fd7\u6765\u53c2\u6570\u5316\u5176\u4ed6\u5bf9\u8c61\u3002\u547d\u4ee4\u6a21\u5f0f\u7c7b\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"435\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11-1024x435.png\" alt=\"\" class=\"wp-image-1053\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11-1024x435.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11-300x127.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11-768x326.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11-1536x652.png 1536w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-11.png 1992w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>\u4e0a\u9762\u7684\u8bbe\u8ba1\u65b9\u6848\u662f\u5efa\u7acb\u5728\u53ea\u6709\u4e00\u4e2a\u6309\u94ae\u7684\u60c5\u51b5\u4e0b\uff0c\u5b9e\u9645\u60c5\u51b5\u662f\u6709\u590d\u6570\u4e2a\u6309\u94ae\u63a7\u5236\u7740\u590d\u6570\u4e2a\u8bbe\u5907\uff0c\u6240\u4ee5\u5728\u63a7\u5236\u5668\u7c7b\u4e2d\u6211\u4eec\u9700\u8981\u7528\u6570\u7ec4\u6216\u5217\u8868\u5b58\u50a8\u5bf9\u5e94\u7684\u547d\u4ee4\u5bf9\u8c61\uff0c\u5e76\u4e14\u6211\u4eec\u628a\u6309\u94ae\u5206\u4e3a\u4e86\u5f00\u548c\u5173\u4e24\u7c7b\uff0c\u8fd9\u5c31\u662f\u8bbe\u8ba1\u65b9\u6848\u4e8c\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public interface Command {\n    public void execute();\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class RemoteControl {\n    Command&#91;] onCommands;\n    Command&#91;] offCommands;\n\n    public RemoteControl() {\n        onCommands = new Command&#91;7];\n        offCommands = new Command&#91;7];\n\n        Command noCommand = new NoCommand();\n        for (int i = 0; i &lt; 7; i++) {\n            onCommands&#91;i] = noCommand;\n            offCommands&#91;i] = noCommand;\n        }\n    }\n\n    public void setCommand(int slot, Command onCommand, Command offCommand) {\n        onCommands&#91;slot] = onCommand;\n        offCommands&#91;slot] = offCommand;\n    }\n\n    public void onButtonWasPushed(int slot) {\n        onCommands&#91;slot].execute();\n    }\n\n    public void offButtonWasPushed(int slot) {\n        offCommands&#91;slot].execute();\n    }\n\n    public String toString() {\n        StringBuffer stringBuff = new StringBuffer();\n        stringBuff.append(\"\\n------ Remote Control ------\\n\");\n        for (int i = 0; i &lt; onCommands.length; i++) {\n            stringBuff.append(\"&#91;slot \" + i + \"] \" + onCommands&#91;i].getClass().getName() + \"  \" + offCommands&#91;i].getClass().getName() + \"\\n\");\n        }\n        return stringBuff.toString();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class NoCommand implements Command {\n    @Override\n    public void execute() {\n\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class LightOnCommand implements Command {\n    Light light;\n\n    public LightOnCommand(Light light) {\n        this.light = light;\n    }\n    @Override\n    public void execute() {\n        light.on();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class LightOffCommand implements Command {\n    Light light;\n\n    public LightOffCommand(Light light) {\n        this.light = light;\n    }\n    @Override\n    public void execute() {\n        light.off();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class RemoteLoader {\n    public static void main(String&#91;] args) {\n        RemoteControl remoteControl = new RemoteControl();\n\n        Light livingRoomLight = new Light(\"Living Room\");\n        Light kitchenLight = new Light(\"Kitchen\");\n\n        Stereo stereo = new Stereo(\"Living Room\");\n\n        LightOnCommand livingRoomLightOn = new LightOnCommand(livingRoomLight);\n        LightOffCommand livingRoomLightOff = new LightOffCommand(livingRoomLight);\n\n        LightOnCommand kitchenLightOn = new LightOnCommand(kitchenLight);\n        LightOffCommand kitchenLightOff = new LightOffCommand(kitchenLight);\n\n        StereoOnWithCDCommand stereoOnWithCDCommand = new StereoOnWithCDCommand(stereo);\n        StereoOffCommand stereoOffCommand = new StereoOffCommand(stereo);\n\n        remoteControl.setCommand(0, livingRoomLightOn, livingRoomLightOff);\n        remoteControl.setCommand(1, kitchenLightOn, kitchenLightOff);\n        remoteControl.setCommand(2, stereoOnWithCDCommand, stereoOffCommand);\n\n        System.out.println(remoteControl);\n\n        remoteControl.onButtonWasPushed(0);\n        remoteControl.offButtonWasPushed(0);\n        remoteControl.onButtonWasPushed(1);\n        remoteControl.offButtonWasPushed(1);\n        remoteControl.onButtonWasPushed(2);\n        remoteControl.offButtonWasPushed(2);\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u7b2c\u4e8c\u79cd\u8bbe\u8ba1\u65b9\u6848\u5bf9\u63a7\u5236\u5668\u8fdb\u884c\u4e86\u4f18\u5316\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5c06\u63a7\u5236\u5668\u4e2d\u7684\u547d\u4ee4\u5b58\u50a8\u5bf9\u8c61\u6539\u6210\u4e86\u6570\u7ec4\uff0c\u8fd9\u6837\u5c31\u80fd\u5b58\u50a8\u590d\u6570\u4e2a\u547d\u4ee4\u5bf9\u8c61\u3002<\/li>\n\n\n\n<li>\u5c06\u6309\u94ae\u5206\u4e3a\u4e86&#8217;\u5f00&#8217;\u7c7b\u578b\u548c&#8217;\u5173&#8217;\u7c7b\u578b\uff0c\u4e0e\u8bbe\u5907\u7684\u6b63\u5e38\u4f7f\u7528\u76f8\u5bf9\u5e94\u3002<\/li>\n\n\n\n<li>\u589e\u52a0\u4e86NoCommand\u7a7a\u5bf9\u8c61\u66ff\u4ee3\u5728\u6570\u7ec4\u7d22\u5f15\u6ca1\u6709\u503c\u65f6\u7684\u4e3a\u7a7a\u5224\u65ad\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u7b2c\u4e8c\u79cd\u8bbe\u8ba1\u65b9\u6848\u7684\u7c7b\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"441\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-1024x441.png\" alt=\"\" class=\"wp-image-1054\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-1024x441.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-300x129.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-768x331.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-1536x662.png 1536w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/05\/image-12-2048x882.png 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>\u5728\u7b2c\u4e8c\u79cd\u8bbe\u8ba1\u65b9\u6848\u4e0a\uff0c\u6211\u4eec\u5728\u63a7\u5236\u5668\u4e2d\u52a0\u5165\u64a4\u9500\u529f\u80fd\u540e\u5c31\u5f62\u6210\u4e86\u7b2c\u4e09\u79cd\u8bbe\u8ba1\u65b9\u6848\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class RemoteControlWithUndo {\n    Command&#91;] onCommands;\n    Command&#91;] offCommands;\n    Command undoCommand;\n\n    public RemoteControlWithUndo() {\n        onCommands = new Command&#91;7];\n        offCommands = new Command&#91;7];\n\n        Command noCommand = new NoCommand();\n        for (int i = 0; i &lt; 7; i++) {\n            onCommands&#91;i] = noCommand;\n            offCommands&#91;i] = noCommand;\n        }\n    }\n\n    public void setCommand(int slot, Command onCommand, Command offCommand) {\n        onCommands&#91;slot] = onCommand;\n        offCommands&#91;slot] = offCommand;\n    }\n\n    public void onButtonWasPushed(int slot) {\n        onCommands&#91;slot].execute();\n        undoCommand = onCommands&#91;slot];\n    }\n\n    public void offButtonWasPushed(int slot) {\n        offCommands&#91;slot].execute();\n        undoCommand = offCommands&#91;slot];\n    }\n\n    public String toString() {\n        StringBuffer stringBuff = new StringBuffer();\n        stringBuff.append(\"\\n------ Remote Control ------\\n\");\n        for (int i = 0; i &lt; onCommands.length; i++) {\n            stringBuff.append(\"&#91;slot \" + i + \"] \" + onCommands&#91;i].getClass().getName() + \"  \" + offCommands&#91;i].getClass().getName() + \"\\n\");\n        }\n        return stringBuff.toString();\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class CeilingFan {\n    public static final int HIGH = 3;\n    public static final int MEDIUM = 2;\n    public static final int LOW = 1;\n    public static final int OFF = 0;\n    String location;\n    int speed;\n\n    public CeilingFan(String location) {\n        this.location = location;\n    }\n\n    public void high() {\n        speed = HIGH;\n    }\n\n    public void medium() {\n        speed = MEDIUM;\n    }\n\n    public void low() {\n        speed = LOW;\n    }\n\n    public void off() {\n        speed = OFF;\n    }\n\n    public int getSpeed() {\n        return speed;\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class CeilingFanHighCommand implements Command {\n    CeilingFan ceilingFan;\n    int prevSpeed;\n\n    public CeilingFanHighCommand(CeilingFan ceilingFan) {\n        this.ceilingFan = ceilingFan;\n    }\n\n    @Override\n    public void execute() {\n        prevSpeed = ceilingFan.getSpeed();\n        ceilingFan.high();\n    }\n\n    public void undo() {\n        if (prevSpeed == CeilingFan.HIGH) {\n            ceilingFan.high();\n        } else if (prevSpeed == CeilingFan.MEDIUM) {\n            ceilingFan.medium();\n        } else if (prevSpeed == CeilingFan.LOW) {\n            ceilingFan.low();\n        } else if (prevSpeed == CeilingFan.OFF) {\n            ceilingFan.off();\n        }\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u529f\u80fd\u4f18\u5316\u540e\u6211\u4eec\u5c31\u6709\u4e86\u73b0\u6709\u7684\u4ee3\u7801\u8bbe\u8ba1\u3002\u540e\u7eed\u7684\u529f\u80fd\u4f18\u5316\u662f\u5728\u4e4b\u524d\u547d\u4ee4\u6a21\u5f0f\u4ee3\u7801\u6846\u67b6\u7684\u57fa\u7840\u4e0a\u8fdb\u884c\u4e86\u529f\u80fd\u7684\u5b8c\u5584\u548c\u63d0\u5347\uff0c\u4f7f\u7528\u7684\u6846\u67b6\u8fd8\u662f\u547d\u4ee4\u6a21\u5f0f\u672c\u8eab\u3002<\/p>\n\n\n\n<p>\u6700\u540e\u6211\u4eec\u5bf9\u547d\u4ee4\u6a21\u5f0f\u4f5c\u4e2a\u603b\u7ed3\uff1a\u547d\u4ee4\u6a21\u5f0f\u5c06\u8bf7\u6c42\u5c01\u88c5\u6210\u5bf9\u8c61\uff0c\u8fd9\u6837\u80fd\u65b9\u4fbf\u540c\u7c7b\u578b\u8bf7\u6c42\u7684\u7ba1\u7406\uff0c\u5305\u62ec\u961f\u5217\u5316\u8bf7\u6c42\u8fdb\u884c\u591a\u7ebf\u7a0b\u63a7\u5236\u4ee5\u8fbe\u5230\u66f4\u65b9\u4fbf\u7684\u8d44\u6e90\u7ba1\u7406\u3001\u65e5\u5fd7\u5316\u8bf7\u6c42\u6765\u589e\u5f3a\u8bf7\u6c42\u7684\u53ef\u9760\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u547d\u4ee4\u6a21\u5f0f\u7684\u76ee\u7684\u662f\u628a\u8bf7\u6c42\u8c03\u7528\u5c01\u88c5\u8d77\u6765\u3002 \u5047\u8bbe\u6211\u4eec\u9700\u8981\u7528\u4e00\u4e2a\u9065\u63a7\u5668\uff0c\u8fd9\u4e2a\u9065\u63a7\u5668\u6709\u4e03\u4e2a\u63d2\u69fd\uff0c\u6bcf\u4e00\u4e2a\u63d2\u69fd\u7531\u4e24\u4e2a\u6309\u94ae\u63a7\u5236 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[80],"tags":[],"class_list":["post-1049","post","type-post","status-publish","format-standard","hentry","category-design-pattern"],"_links":{"self":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/comments?post=1049"}],"version-history":[{"count":4,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1049\/revisions"}],"predecessor-version":[{"id":1057,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1049\/revisions\/1057"}],"wp:attachment":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/media?parent=1049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/categories?post=1049"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/tags?post=1049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}