{"id":1085,"date":"2024-06-07T15:51:59","date_gmt":"2024-06-07T07:51:59","guid":{"rendered":"http:\/\/www.spiceandwolf.com.cn\/?p=1085"},"modified":"2024-09-15T10:06:01","modified_gmt":"2024-09-15T02:06:01","slug":"design-pattern-state-pattern","status":"publish","type":"post","link":"http:\/\/www.spiceandwolf.com.cn\/index.php\/design-pattern-state-pattern\/","title":{"rendered":"\u8bbe\u8ba1\u6a21\u5f0f-\u72b6\u6001\u6a21\u5f0f"},"content":{"rendered":"\n<p><strong>\u72b6\u6001\u6a21\u5f0f<\/strong>\u5141\u8bb8\u5bf9\u8c61\u5728\u5185\u90e8\u72b6\u6001\u6539\u53d8\u65f6\u6539\u53d8\u5b83\u7684\u884c\u4e3a\uff0c\u5bf9\u8c61\u770b\u8d77\u6765\u597d\u50cf\u4fee\u6539\u4e86\u5b83\u7684\u7c7b\u3002<\/p>\n\n\n\n<p>\u73b0\u5728\u6709\u4e00\u4e2a\u573a\u666f\uff1a\u4f60\u9700\u8981\u8bbe\u8ba1\u51fa\u4e00\u4e2a\u7cd6\u679c\u673a\uff0c\u8ba9\u5b83\u80fd\u6b63\u5e38\u8fdb\u884c\u7cd6\u679c\u51fa\u552e\u7b49\u884c\u4e3a\u3002\u72b6\u6001\u8f6c\u6362\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"809\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1024x809.png\" alt=\"\" class=\"wp-image-1088\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1024x809.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-300x237.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-768x607.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image.png 1248w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>\u8fd9\u662f\u53ef\u80fd\u7684\u521d\u7ea7\u8bbe\u8ba1\u65b9\u6848\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class GumballMachine {\n    final static int SOLD_OUT = 0;\n    final static int NO_QUARTER = 1;\n    final static int HAS_QUARTER = 2;\n    final static int SOLD = 3;\n\n    int state = SOLD_OUT;\n    int count = 0;\n\n    public GumballMachine(int count) {\n        this.count = count;\n        if (count > 0) {\n            state = NO_QUARTER;\n        }\n    }\n\n    public void insertQuarter() {\n        if (state == HAS_QUARTER) {\n            System.out.println(\"You can't insert another quarter\");\n        } else if (state == NO_QUARTER) {\n            state = HAS_QUARTER;\n            System.out.println(\"You inserted a quarter\");\n        } else if (state == SOLD_OUT) {\n            System.out.println(\"You can't insert a quarter, the machine is sold out\");\n        } else if (state == SOLD) {\n            System.out.println(\"Please wait, we're already giving you a gumball\");\n        }\n    }\n\n    public void ejectQuarter() {\n        if (state == HAS_QUARTER) {\n            System.out.println(\"Quarter retured\");\n            state = NO_QUARTER;\n        } else if (state == NO_QUARTER) {\n            System.out.println(\"You haven't inserted a quarter\");\n        } else if (state == SOLD) {\n            System.out.println(\"Sorry, you already turned the crank\");\n        } else if (state == SOLD_OUT) {\n            System.out.println(\"You can't eject, you haven't inserted a quarter yet\");\n        }\n    }\n\n    public void turnCrank() {\n        if (state == SOLD) {\n            System.out.println(\"Turning twice doesn't get you another gumball\");\n        } else if (state == NO_QUARTER) {\n            System.out.println(\"You turned but there's no quarter\");\n        } else if (state == SOLD_OUT) {\n            System.out.println(\"You turned but there are no gumball\");\n        } else if (state == HAS_QUARTER) {\n            System.out.println(\"You turned...\");\n            state = SOLD;\n            dispense();\n        }\n    }\n\n    public void dispense() {\n        if (state == SOLD) {\n            System.out.println(\"A gumball comes rolling out the slot\");\n            count = count - 1;\n            if (count == 0) {\n                System.out.println(\"Oops, out of gumball\");\n                state = SOLD_OUT;\n            } else {\n                state = NO_QUARTER;\n            }\n        } else if (state == NO_QUARTER) {\n            System.out.println(\"You need to pay first\");\n        } else if (state == SOLD_OUT) {\n            System.out.println(\"No gumball dispensed\");\n        } else if (state == HAS_QUARTER) {\n            System.out.println(\"No gumball dispensed\");\n        }\n    }\n\n    @Override\n    public String toString() {\n        if (state == SOLD_OUT) {\n            return \"Machine is sold out\";\n        } else if (state == NO_QUARTER) {\n            return \"Mahcine is waiting for quarter\";\n        } else if (state == HAS_QUARTER) {\n            return \"Machine is waiting for crank\";\n        } else if (state == SOLD) {\n            return \"Machine is solding\";\n        } else {\n            return \"\";\n        }\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u73b0\u5728\u6211\u4eec\u52a0\u5165\u4e00\u4e2a\u65b0\u7684\u9700\u6c42\uff1a\u5f53\u6295\u5165\u786c\u5e01\u5e76\u8f6c\u52a8\u66f2\u67c4\u65f6\uff0c\u670910%\u6982\u7387\u4f1a\u83b7\u5f97\u4e24\u4e2a\u7cd6\u679c\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3a\u8d62\u5bb6\u72b6\u6001\u3002\u8fd9\u662f\u4e00\u4e2a\u65b0\u589e\u7684\u72b6\u6001\uff0c\u5982\u679c\u6cbf\u7528\u521d\u59cb\u8bbe\u8ba1\uff0c\u6211\u4eec\u589e\u52a0\u65b0\u72b6\u6001\u65f6\u4e0d\u5f97\u4e0d\u4fee\u6539\u539f\u6709\u4ee3\u7801\uff0c\u8fd9\u6837\u7684\u8bbe\u8ba1\u5e76\u6ca1\u6709\u53ef\u6269\u5c55\u6027\uff0c\u6240\u4ee5\u6211\u4eec\u6253\u7b97\u7528\u72b6\u6001\u6a21\u5f0f\u5bf9\u4ee3\u7801\u8fdb\u884c\u4f18\u5316\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public interface State {\n    public void insertQuarter();\n    public void ejectQuarter();\n    public void turnCrank();\n    public void dispense();\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class GumballMachine {\n    State soldOutState;\n    State noQuarterState;\n    State hasQuarterState;\n    State soldState;\n\n    State state = soldOutState;\n    int count = 0;\n\n    public GumballMachine(int numberGumballs) {\n        soldOutState = new SoldOutState(this);\n        noQuarterState = new NoQuarterState(this);\n        hasQuarterState = new HasQuarterState(this);\n        soldState = new SoldState(this);\n        this.count = numberGumballs;\n        if (numberGumballs > 0) {\n            state = noQuarterState;\n        }\n    }\n\n    public void insertQuarter() {\n        state.insertQuarter();\n    }\n\n    public void ejectQuarter() {\n        state.ejectQuarter();\n    }\n\n    public void turnCrank() {\n        state.turnCrank();\n        state.dispense();\n    }\n\n    public void setState(State state) {\n        this.state = state;\n    }\n\n    void releaseBall() {\n        System.out.println(\"A gumball comes rolling out the slot...\");\n        if (count != 0) {\n            count = count - 1;\n        }\n    }\n\n    public State getSoldOutState() {\n        return soldOutState;\n    }\n\n    public State getNoQuarterState() {\n        return noQuarterState;\n    }\n\n    public State getHasQuarterState() {\n        return hasQuarterState;\n    }\n\n    public State getSoldState() {\n        return soldState;\n    }\n\n    public int getCount() {\n        return count;\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class HasQuarterState implements State {\n    GumballMachine gumballMachine;\n\n    public HasQuarterState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n    @Override\n    public void insertQuarter() {\n        System.out.println(\"You can't insert another quarter\");\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"Quarter returned\");\n        gumballMachine.setState(gumballMachine.getNoQuarterState());\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"You turned...\");\n        gumballMachine.setState(gumballMachine.getSoldState());\n    }\n\n    @Override\n    public void dispense() {\n        System.out.println(\"No gumball dispensed\");\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class NoQuarterState implements State {\n    GumballMachine gumballMachine;\n\n    public NoQuarterState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n\n    @Override\n    public void insertQuarter() {\n        System.out.println(\"You inserted a quarter\");\n        gumballMachine.setState(gumballMachine.getHasQuarterState());\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"You haven't inserted a quarter\");\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"You turned, but there's no quarter\");\n    }\n\n    @Override\n    public void dispense() {\n        System.out.println(\"You need to pay first\");\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class SoldOutState implements State {\n    GumballMachine gumballMachine;\n\n    public SoldOutState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n    @Override\n    public void insertQuarter() {\n        System.out.println(\"Candy has been solded out\");\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"Candy has been solded out\");\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"Candy has been solded out\");\n    }\n\n    @Override\n    public void dispense() {\n        System.out.println(\"Candy has been solded out\");\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class SoldState implements State {\n    GumballMachine gumballMachine;\n\n    public SoldState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n    @Override\n    public void insertQuarter() {\n        System.out.println(\"Please wait, we're already giving you a gumball\");\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"Sorry, you already turned the crank\");\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"Turning twice doesn't get you another gumball\");\n    }\n\n    @Override\n    public void dispense() {\n        gumballMachine.releaseBall();\n        if (gumballMachine.getCount() > 0) {\n            gumballMachine.setState(gumballMachine.getNoQuarterState());\n        } else {\n            System.out.println(\"Oops, out of gumballs\");\n            gumballMachine.setState(gumballMachine.getSoldOutState());\n        }\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u56e0\u4e3a\u884c\u4e3a\u6ca1\u6709\u53d8\u5316\uff0c\u6211\u4eec\u628a\u884c\u4e3a\u7edf\u4e00\u5230\u72b6\u6001\u63a5\u53e3\u4e2d\u53bb\uff0c\u8fd9\u6837\u5728\u589e\u52a0\u72b6\u6001\u65f6\u5c31\u4e0d\u9700\u8981\u6539\u53d8\u539f\u6709\u7684\u884c\u4e3a\u4ee3\u7801\uff0c\u5b9e\u73b0\u4e86\u72b6\u6001\u4e4b\u95f4\u884c\u4e3a\u5b9e\u73b0\u7684\u89e3\u8026\u3002<\/p>\n\n\n\n<p>\u6700\u540e\u6211\u4eec\u65b0\u589e\u8d62\u5bb6\u72b6\u6001\uff0c\u5e76\u5bf9\u5176\u4ed6\u903b\u8f91\u8fdb\u884c\u8c03\u6574\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class WinnerState implements State {\n    GumballMachine gumballMachine;\n    \n    public WinnerState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n    \n    @Override\n    public void insertQuarter() {\n        System.out.println(\"Please wait, we're already giving you a gumball\");\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"Sorry, you already turned the crank\");\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"Turning twice doesn't get you another gumball\");\n    }\n\n    @Override\n    public void dispense() {\n        System.out.println(\"You're a winner! You get two gumballs for your quarter\");\n        gumballMachine.releaseBall();\n        if (gumballMachine.getCount() == 0) {\n            gumballMachine.setState(gumballMachine.getSoldOutState());\n        } else {\n            gumballMachine.releaseBall();\n            if (gumballMachine.getCount() > 0) {\n                gumballMachine.setState(gumballMachine.getNoQuarterState());\n            } else {\n                System.out.println(\"Oops, out of gumballs\");\n                gumballMachine.setState(gumballMachine.getSoldOutState());\n            }\n        }\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class HasQuarterState implements State {\n    GumballMachine gumballMachine;\n    Random randomWinner = new Random(System.currentTimeMillis());\n\n    public HasQuarterState(GumballMachine gumballMachine) {\n        this.gumballMachine = gumballMachine;\n    }\n    @Override\n    public void insertQuarter() {\n        System.out.println(\"You can't insert another quarter\");\n    }\n\n    @Override\n    public void ejectQuarter() {\n        System.out.println(\"Quarter returned\");\n        gumballMachine.setState(gumballMachine.getNoQuarterState());\n    }\n\n    @Override\n    public void turnCrank() {\n        System.out.println(\"You turned...\");\n        int winner = randomWinner.nextInt(10);\n        if ((winner == 0) &amp;&amp; (gumballMachine.getCount() > 1)) {\n            gumballMachine.setState(gumballMachine.getWinnerState());\n        } else {\n            gumballMachine.setState(gumballMachine.getSoldState());\n        }\n    }\n\n    @Override\n    public void dispense() {\n        System.out.println(\"No gumball dispensed\");\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class GumballMachine {\n    State soldOutState;\n    State noQuarterState;\n    State hasQuarterState;\n    State soldState;\n    State winnerState;\n\n    State state = soldOutState;\n    int count = 0;\n\n    public GumballMachine(int numberGumballs) {\n        soldOutState = new SoldOutState(this);\n        noQuarterState = new NoQuarterState(this);\n        hasQuarterState = new HasQuarterState(this);\n        soldState = new SoldState(this);\n        winnerState = new WinnerState(this);\n        this.count = numberGumballs;\n        if (numberGumballs > 0) {\n            state = noQuarterState;\n        }\n    }\n\n    public void insertQuarter() {\n        state.insertQuarter();\n    }\n\n    public void ejectQuarter() {\n        state.ejectQuarter();\n    }\n\n    public void turnCrank() {\n        state.turnCrank();\n        state.dispense();\n    }\n\n    public void setState(State state) {\n        this.state = state;\n    }\n\n    void releaseBall() {\n        System.out.println(\"A gumball comes rolling out the slot...\");\n        if (count != 0) {\n            count = count - 1;\n        }\n    }\n\n    public State getSoldOutState() {\n        return soldOutState;\n    }\n\n    public State getNoQuarterState() {\n        return noQuarterState;\n    }\n\n    public State getHasQuarterState() {\n        return hasQuarterState;\n    }\n\n    public State getSoldState() {\n        return soldState;\n    }\n\n    public State getWinnerState() {\n        return winnerState;\n    }\n\n    public int getCount() {\n        return count;\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u72b6\u6001\u6a21\u5f0f\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=\"479\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1-1024x479.png\" alt=\"\" class=\"wp-image-1090\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1-1024x479.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1-300x140.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1-768x359.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/06\/image-1.png 1378w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>\u72b6\u6001\u6a21\u5f0f\u5141\u8bb8\u5bf9\u8c61\u5728\u5185\u90e8\u72b6\u6001\u6539\u53d8\u65f6\u6539\u53d8\u5b83\u7684\u884c\u4e3a\uff0c\u5bf9\u8c61\u770b\u8d77\u6765\u597d\u50cf\u4fee\u6539\u4e86\u5b83\u7684\u7c7b\u3002 \u73b0\u5728\u6709\u4e00\u4e2a\u573a\u666f\uff1a\u4f60\u9700\u8981\u8bbe\u8ba1\u51fa\u4e00\u4e2a\u7cd6 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25,80],"tags":[],"class_list":["post-1085","post","type-post","status-publish","format-standard","hentry","category-code","category-design-pattern"],"_links":{"self":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1085","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=1085"}],"version-history":[{"count":3,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1085\/revisions"}],"predecessor-version":[{"id":1091,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/1085\/revisions\/1091"}],"wp:attachment":[{"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/media?parent=1085"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/categories?post=1085"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.spiceandwolf.com.cn\/index.php\/wp-json\/wp\/v2\/tags?post=1085"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}