{"componentChunkName":"component---src-templates-post-template-jsx","path":"/history/posts/2020-10-04--001.md","result":{"data":{"site":{"siteMetadata":{"title":"Blog by Eunyoung","subtitle":"작업 기록 블로그","copyright":"© All rights reserved.","author":{"name":"EunYoung","twitter":"#"},"disqusShortname":"","url":"https://ssongey.github.io"}},"markdownRemark":{"id":"b473c3ca-8ab6-5486-a455-04ac89ad166d","html":"<h2>열거 타입(Enumeration Type)</h2>\n<ul>\n<li>한정된 값만을 갖는 데이터 타입</li>\n<li>한정된 값은 열거 상수(Enumeration Constant)로 정의</li>\n</ul>\n<h2>열거 타입 변수</h2>\n<ul>\n<li>\n<p>열거 타입 변수 선언</p>\n<div class=\"gatsby-highlight\" data-language=\"text\"><pre class=\"language-text\"><code class=\"language-text\">Week today;</code></pre></div>\n</li>\n<li>\n<p>열거 상수 값 저장 (열거 타입 변수값은 열거 상수 중 하나)</p>\n<div class=\"gatsby-highlight\" data-language=\"text\"><pre class=\"language-text\"><code class=\"language-text\">Week today = Week.SUNDAY;</code></pre></div>\n</li>\n<li>\n<p>열거변수는 참조타입</p>\n<div class=\"gatsby-highlight\" data-language=\"text\"><pre class=\"language-text\"><code class=\"language-text\">Week today = null;</code></pre></div>\n<p>열거 타입 변수는 참조 타입\n열거 타입 변수는 참조 타입이므로 null 값 저장 가능</p>\n</li>\n</ul>\n<h3>열거 상수는 열거 객체를 참조한다</h3>\n<p>\n  <a\n    class=\"gatsby-resp-image-link\"\n    href=\"/devHistoryBlog/static/8072482908af9b99e86957ebe49be105/49217/001--1.png\"\n    style=\"display: block\"\n    target=\"_blank\"\n    rel=\"noopener\"\n  >\n  \n  <span\n    class=\"gatsby-resp-image-wrapper\"\n    style=\"position: relative; display: block;  max-width: 701px; margin-left: auto; margin-right: auto;\"\n  >\n    <span\n      class=\"gatsby-resp-image-background-image\"\n      style=\"padding-bottom: 67.91666666666667%; position: relative; bottom: 0; left: 0; background-image: url('data:image/png;base64,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'); background-size: cover; display: block;\"\n    >\n      <img\n        class=\"gatsby-resp-image-image\"\n        style=\"width: 100%; height: 100%; margin: 0; vertical-align: middle; position: absolute; top: 0; left: 0; box-shadow: inset 0px 0px 0px 400px white;\"\n        alt=\"001  1\"\n        title=\"\"\n        src=\"/devHistoryBlog/static/8072482908af9b99e86957ebe49be105/49217/001--1.png\"\n        srcset=\"/devHistoryBlog/static/8072482908af9b99e86957ebe49be105/8ff5a/001--1.png 240w,\n/devHistoryBlog/static/8072482908af9b99e86957ebe49be105/e85cb/001--1.png 480w,\n/devHistoryBlog/static/8072482908af9b99e86957ebe49be105/49217/001--1.png 701w\"\n        sizes=\"(max-width: 701px) 100vw, 701px\"\n      />\n    </span>\n  </span>\n  \n  </a>\n    </p>\n<div class=\"gatsby-highlight\" data-language=\"text\"><pre class=\"language-text\"><code class=\"language-text\">Week week1 = Week.SUNDAY;\nWeek week2 = Week.SUMDAY;\n\nSystem.out.println(wee1 == week2); // true</code></pre></div>\n<p>week1, week2 모두 참조 타입으로<br>\n힙에 생성된 Week.SUNDAY 객체의 주소값을 가지고 있으므로\n주소 비교시 true 가 출력된다.</p>\n<h2>열거 객체의 메소드</h2>\n<ul>\n<li>열거 객체는 열거 상수의 문자열을 내부 데이터로 가지고 있음</li>\n<li>\n<p>열거 타입은 컴파일 시 java.lang.Enum 클래스를 자동 상속<br>\n열거 객체는 java.lang.Enum  클래스의 메소드 사용 가능\n\n  <a\n    class=\"gatsby-resp-image-link\"\n    href=\"/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/1ac29/001--2.png\"\n    style=\"display: block\"\n    target=\"_blank\"\n    rel=\"noopener\"\n  >\n  \n  <span\n    class=\"gatsby-resp-image-wrapper\"\n    style=\"position: relative; display: block;  max-width: 960px; margin-left: auto; margin-right: auto;\"\n  >\n    <span\n      class=\"gatsby-resp-image-background-image\"\n      style=\"padding-bottom: 27.083333333333332%; position: relative; bottom: 0; left: 0; background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAFCAYAAABFA8wzAAAACXBIWXMAABJ0AAASdAHeZh94AAABEElEQVQY0y2Q2XKDMAxF+f9/6/ShmUynbMaYxQZCgBhjltxeaB80sjXy0ZED/bD4vCe4JxWEnpA3L9zjEl9hjo9bhFC2rFkk1QhR/4U0E36kwS1UKDoH1drrbTs4BH47kBc1mseA17LD+Q2z3yHyAqrScOuBhaG7AVGaIRISqVT4DmMIWcB0PZ6jxbxsOFnBdrzxHCZMs4f9L87Oc0iF4gRywLrjGphmOWICBbMgtKwMEt6jRKAnYycr8OvGBgnT9peN8ytBNRszSFXCNB2Bb3T9eEFiPj4j4wbxacxzVWtYt2DbabjQIEkFVFlfq3nquGWFNi2a9sEaDWk9Wv4VrWttkKmCthI5c8ktTgZbLuAvOcV4Dt8MExEAAAAASUVORK5CYII='); background-size: cover; display: block;\"\n    >\n      <img\n        class=\"gatsby-resp-image-image\"\n        style=\"width: 100%; height: 100%; margin: 0; vertical-align: middle; position: absolute; top: 0; left: 0; box-shadow: inset 0px 0px 0px 400px white;\"\n        alt=\"001  2\"\n        title=\"\"\n        src=\"/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/d9199/001--2.png\"\n        srcset=\"/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/8ff5a/001--2.png 240w,\n/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/e85cb/001--2.png 480w,\n/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/d9199/001--2.png 960w,\n/devHistoryBlog/static/283d508245c5b8baa6ffb188d3bda755/1ac29/001--2.png 1022w\"\n        sizes=\"(max-width: 960px) 100vw, 960px\"\n      />\n    </span>\n  </span>\n  \n  </a>\n    </p>\n<div class=\"gatsby-highlight\" data-language=\"text\"><pre class=\"language-text\"><code class=\"language-text\">Week today = Week.SUNDAY;\ntoday.name(); // SUNDAY\ntoday.ordinal(); // 0 (enum 순서는 0부터 시작)\ntoday.valueOf(&quot;SUNDAY&quot;) // Week.SUNDAY</code></pre></div>\n</li>\n</ul>","fields":{"tagSlugs":["/tags/책리뷰/","/tags/이것이자바다/"],"slug":"/history/posts/2020-10-04--001.md"},"frontmatter":{"title":"[Java] Enum","tags":["책리뷰","이것이자바다"],"date":"2020-10-04","description":""}}},"pageContext":{"slug":"/history/posts/2020-10-04--001.md"}},"staticQueryHashes":[]}