{"id":37203,"date":"2023-06-13T22:55:57","date_gmt":"2023-06-13T13:55:57","guid":{"rendered":"https:\/\/m9js.shop\/blog\/?p=37203"},"modified":"2023-06-13T22:55:57","modified_gmt":"2023-06-13T13:55:57","slug":"java-state-design-pattern-how-to-change-behavior-based-on-an-objects-internal-state","status":"publish","type":"post","link":"https:\/\/m9js.shop\/blog\/development\/java-state-design-pattern-how-to-change-behavior-based-on-an-objects-internal-state","title":{"rendered":"\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134: \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95"},"content":{"rendered":"

\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc774\ub780?<\/h1>\n
\uc18c\ud504\ud2b8\uc6e8\uc5b4 \uac1c\ubc1c\uc5d0\uc11c \uc124\uacc4 \ud328\ud134(design pattern)\uc740 \ud2b9\uc815 \ubb38\uc81c\ub97c \ud574\uacb0\ud558\uae30 \uc704\ud55c \uc7ac\uc0ac\uc6a9 \uac00\ub2a5\ud55c \ud574\uacb0\ucc45\uc785\ub2c8\ub2e4. \ub514\uc790\uc778 \ud328\ud134\uc740 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uc544\ud0a4\ud14d\ucc98\uc5d0\uc11c \uc801\uc6a9\ub418\uba70, \uc774\ub97c \ud1b5\ud574 \uac1c\ubc1c\uc790\ub294 \ucf54\ub4dc\uc758 \uc720\uc9c0\ubcf4\uc218\uc131\uacfc \ud655\uc7a5\uc131\uc744 \ud5a5\uc0c1\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4 \uc9c0\ud5a5 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uac1c\ubc1c\uc5d0\uc11c \ub9e4\uc6b0 \uc720\uc6a9\ud55c \ud328\ud134\uc785\ub2c8\ub2e4. \uc774 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc774 \ubc29\ubc95\uc740 \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub418\uace0 \uadf8\uc5d0 \ub530\ub77c \ub3d9\uc791\uc774 \ubcc0\uacbd\ub420 \ub54c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc73c\uba70, \uc774\ub97c \ud1b5\ud574 \uc18c\ud504\ud2b8\uc6e8\uc5b4\uc758 \uc720\uc9c0\ubcf4\uc218\uc131\uacfc \ud655\uc7a5\uc131\uc744 \ud5a5\uc0c1\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
$\"Java$ <\/p>\n

\uac1d\uccb4 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95<\/h2>\n
\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc774 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub418\uba74 \uac1d\uccb4\uc758 \ub3d9\uc791\ub3c4 \ubcc0\uacbd\ub429\ub2c8\ub2e4. \uc774\ub7ec\ud55c \ub3d9\uc791 \ubcc0\uacbd\uc740 \uac1d\uccb4 \uc9c0\ud5a5 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uac1c\ubc1c\uc5d0\uc11c \ub9e4\uc6b0 \uc720\uc6a9\ud569\ub2c8\ub2e4. \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub418\uba74 \uac1d\uccb4\uc758 \ub3d9\uc791\ub3c4 \ubcc0\uacbd\ub418\uae30 \ub54c\ubb38\uc5d0, \uac1c\ubc1c\uc790\ub294 \ucf54\ub4dc\ub97c \uc218\uc815\ud558\uc9c0 \uc54a\uace0\ub3c4 \uac1d\uccb4\uc758 \ub3d9\uc791\uc744 \ubcc0\uacbd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ub294 \uc18c\ud504\ud2b8\uc6e8\uc5b4\uc758 \uc720\uc9c0\ubcf4\uc218\uc131\uacfc \ud655\uc7a5\uc131\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \ub370 \ud070 \ub3c4\uc6c0\uc774 \ub429\ub2c8\ub2e4.<\/p>\n

\uc2a4\ud14c\uc774\ud2b8 \ud328\ud134\uc758 \uad6c\uc131\uc694\uc18c\uc640 \uc791\ub3d9 \uc6d0\ub9ac<\/h2>\n
\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc774 \ud328\ud134\uc740 \uc138 \uac00\uc9c0 \uad6c\uc131\uc694\uc18c\ub85c \uc774\ub8e8\uc5b4\uc838 \uc788\uc2b5\ub2c8\ub2e4. \uccab \ubc88\uc9f8\ub294 \uc0c1\ud0dc(State)\uc785\ub2c8\ub2e4. \uc0c1\ud0dc\ub294 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\ub97c \ub098\ud0c0\ub0b4\uba70, \uc774 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \uac1d\uccb4\uc758 \ub3d9\uc791\uc774 \ubcc0\uacbd\ub429\ub2c8\ub2e4. \ub450 \ubc88\uc9f8\ub294 \uc0c1\ud0dc \uc804\ud658(Transition)\uc785\ub2c8\ub2e4. \uc0c1\ud0dc \uc804\ud658\uc740 \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub420 \ub54c \uc218\ud589\ub429\ub2c8\ub2e4. \uc138 \ubc88\uc9f8\ub294 \ucee8\ud14d\uc2a4\ud2b8(Context)\uc785\ub2c8\ub2e4. \ucee8\ud14d\uc2a4\ud2b8\ub294 \uc0c1\ud0dc\ub97c \uac00\uc9c0\uace0 \uc788\ub294 \uac1d\uccb4\uc785\ub2c8\ub2e4. \uc774 \ucee8\ud14d\uc2a4\ud2b8\ub294 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\uace0, \uc0c1\ud0dc\ub97c \ubcc0\uacbd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\uc2a4\ud14c\uc774\ud2b8 \ud328\ud134\uc740 \ub2e4\uc74c\uacfc \uac19\uc740 \uc791\ub3d9 \uc6d0\ub9ac\ub97c \uac00\uc9c0\uace0 \uc788\uc2b5\ub2c8\ub2e4. \uba3c\uc800, \uac1d\uccb4\ub294 \ucd08\uae30 \uc0c1\ud0dc\ub97c \uac00\uc9c0\uace0 \uc788\uc2b5\ub2c8\ub2e4. \uc774 \uc0c1\ud0dc\uc5d0\uc11c \uac1d\uccb4\ub294 \ucd08\uae30 \ub3d9\uc791\uc744 \uc218\ud589\ud569\ub2c8\ub2e4. \uadf8\ub9ac\uace0 \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub420 \ub54c\ub9c8\ub2e4, \uac1d\uccb4\ub294 \uc0c8\ub85c\uc6b4 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \uc218\ud589\ud569\ub2c8\ub2e4. \uc774\ub807\uac8c \uac1d\uccb4\uc758 \uc0c1\ud0dc\uac00 \ubcc0\uacbd\ub420 \ub54c\ub9c8\ub2e4, \uac1d\uccb4\ub294 \uc0c8\ub85c\uc6b4 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \uc218\ud589\ud558\uac8c \ub429\ub2c8\ub2e4.<\/p>\n

\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ud328\ud134 \uc608\uc81c \ubc0f \ud65c\uc6a9 \ubc29\uc548<\/h2>\n

\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc774 \ud328\ud134\uc740 \ub9e4\uc6b0 \uc720\uc6a9\ud558\uba70, \ub2e4\uc591\ud55c \uc608\uc81c\uc640 \ud65c\uc6a9 \ubc29\uc548\uc774 \uc788\uc2b5\ub2c8\ub2e4. \uc774\uc81c, \uac04\ub2e8\ud55c \uc608\uc81c\ub97c \ud1b5\ud574 \uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ud328\ud134\uc744 \uc0b4\ud3b4\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n

public interface State {\n    void doAction(Context context);\n}\n\npublic class StartState implements State {\n    public void doAction(Context context) {\n        System.out.println(\"Player is in start state\");\n        context.setState(this);\n    }\n}\n\npublic class StopState implements State {\n    public void doAction(Context context) {\n        System.out.println(\"Player is in stop state\");\n        context.setState(this);\n    }\n}\n\npublic class Context {\n    private State state;\n\n    public Context(){\n        state = null;\n    }\n\n    public void setState(State state){\n        this.state = state;\n    }\n\n    public State getState(){\n        return state;\n    }\n}<\/code><\/pre>\n\uc704 \ucf54\ub4dc\ub294 \uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ud328\ud134\uc758 \uc608\uc81c\uc785\ub2c8\ub2e4. \uc774 \uc608\uc81c\ub294 \ucee8\ud14d\uc2a4\ud2b8\ub97c \ub098\ud0c0\ub0b4\ub294 Context \ud074\ub798\uc2a4\uc640 \uc0c1\ud0dc\ub97c \ub098\ud0c0\ub0b4\ub294 State \uc778\ud130\ud398\uc774\uc2a4, \uadf8\ub9ac\uace0 StartState\uc640 StopState \ud074\ub798\uc2a4\ub85c \uc774\ub8e8\uc5b4\uc838 \uc788\uc2b5\ub2c8\ub2e4. StartState\uc640 StopState \ud074\ub798\uc2a4\ub294 State \uc778\ud130\ud398\uc774\uc2a4\ub97c \uad6c\ud604\ud569\ub2c8\ub2e4. Context \ud074\ub798\uc2a4\ub294 State \uc778\ud130\ud398\uc774\uc2a4\ub97c \uac00\uc9c0\uace0 \uc788\uc73c\uba70, \uc774\ub97c \ud1b5\ud574 \uc0c1\ud0dc\ub97c \ubcc0\uacbd\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc774 \ud328\ud134\uc740 \uac1d\uccb4 \uc9c0\ud5a5 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uac1c\ubc1c\uc5d0\uc11c \ub9e4\uc6b0 \uc720\uc6a9\ud569\ub2c8\ub2e4. \uc774\ub97c \ud1b5\ud574 \uac1d\uccb4\uc758 \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\uace0, \uc18c\ud504\ud2b8\uc6e8\uc5b4\uc758 \uc720\uc9c0\ubcf4\uc218\uc131\uacfc \ud655\uc7a5\uc131\uc744 \ud5a5\uc0c1\uc2dc\ud0ac \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub530\ub77c\uc11c, \uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134\uc740 \uac1d\uccb4 \uc9c0\ud5a5 \uc18c\ud504\ud2b8\uc6e8\uc5b4 \uac1c\ubc1c\uc5d0\uc11c \ubc18\ub4dc\uc2dc \uc54c\uc544\uc57c \ud560 \uc911\uc694\ud55c \uac1c\ub150 \uc911 \ud558\ub098\uc785\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"
\uc790\ubc14 \uc2a4\ud14c\uc774\ud2b8 \ub514\uc790\uc778 \ud328\ud134: \uac1d\uccb4\uc758 \ub0b4\ubd80 \uc0c1\ud0dc\uc5d0 \ub530\ub77c \ub3d9\uc791\uc744 \ubcc0\uacbd\ud558\ub294 \ubc29\ubc95<\/p>\n","protected":false},"author":1,"featured_media":33704,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1957],"tags":[2131,2523,2188,471,2584,3291,5925,3414],"class_list":["post-37203","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-development","tag-design","tag-pattern","tag-public","tag-state","tag-system","tag-3291","tag-5925","tag-3414"],"acf":[],"_links":{"self":[{"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/posts\/37203","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/comments?post=37203"}],"version-history":[{"count":1,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/posts\/37203\/revisions"}],"predecessor-version":[{"id":37276,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/posts\/37203\/revisions\/37276"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/media\/33704"}],"wp:attachment":[{"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/media?parent=37203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/categories?post=37203"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m9js.shop\/blog\/wp-json\/wp\/v2\/tags?post=37203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}