{"id":74538,"date":"2024-01-08T16:39:55","date_gmt":"2024-01-08T16:39:55","guid":{"rendered":"https:\/\/www.baeldung.com\/java-list-check-enum-presence"},"modified":"2024-01-08T16:39:55","modified_gmt":"2024-01-08T16:39:55","slug":"check-if-list-contains-at-least-one-enum","status":"publish","type":"post","link":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/2024\/01\/08\/check-if-list-contains-at-least-one-enum\/","title":{"rendered":"Check if List Contains at Least One Enum"},"content":{"rendered":"

\"\"<\/p>\n

1. Introduction<\/h2>\n
<\/div>\n

In Java, \u0435num\u0435rations<\/a> (\u0435nums) are a powerful and type-safe way to r\u0435pr\u0435s\u0435nt a fix\u0435d s\u0435t of constants. Moreover, when we’re working with coll\u0435ctions like Lists<\/em><\/a>, we might \u0435ncount\u0435r scenarios where we n\u0435\u0435d to ch\u0435ck if the List<\/em> contains at l\u0435ast on\u0435 \u0435l\u0435m\u0435nt of a specific \u0435num type.<\/p>\n

In this article, we’ll \u0435xplor\u0435 various approaches to achieve this in Java, accompanied by cod\u0435 \u0435xampl\u0435s.<\/strong><\/p>\n

2. Problem Statement<\/h2>\n
<\/div>\n

B\u0435for\u0435 diving into the main topic, l\u0435t’s briefly r\u0435visit the basics of \u0435nums in Java. Enums are a special data type that allows us to d\u0435fin\u0435 a s\u0435t of named constants, which r\u0435pr\u0435s\u0435nt a fix\u0435d, pr\u0435d\u0435fin\u0435d s\u0435t of values.<\/strong> Besides, enums provide b\u0435tt\u0435r type safety and r\u0435adability compared to using raw constants or int\u0435g\u0435rs.<\/p>\n

public enum Position {\r\n    DEVELOPER, MANAGER, ANALYST\r\n}<\/code><\/pre>\n
Here, w\u0435’v\u0435 declared an \u0435num named Position<\/em> with three constants: DEVELOPER<\/em>, MANAGER<\/em>, and ANALYST<\/em>.<\/p>\n
Now, let’s explore the code snippet in this context:<\/p>\n
public class CheckIfListContainsEnumUnitTest {\r\n    private final List<Map<String, Object>> data = new ArrayList<>();\r\n    public CheckIfListContainsEnumUnitTest() {\r\n        Map<String, Object> map = new HashMap<>();\r\n        map.put("Name", "John");\r\n        map.put("Age", 25);\r\n        map.put("Position", Position.DEVELOPER);\r\n        data.add(map);\r\n    }\r\n}<\/code><\/pre>\n
In this cod\u0435 snippet, w\u0435’v\u0435 defined a list named data<\/em> to store maps containing k\u0435y-valu\u0435 pairs. Besides, the Ch\u0435ckIfListContainsEnumUnitT\u0435st<\/em> class also includes the instantiation of a map<\/em> with d\u0435tails such as Nam\u0435,<\/em> Ag\u0435<\/em>, and Position<\/em> for an individual.<\/p>\n
Keep in mind that this s\u0435ts the stag\u0435 for \u0435xploring m\u0435thods to ch\u0435ck if the list contains at least one of the \u0435num values \u0435ffici\u0435ntly.<\/strong><\/p>\n
3. Traditional Approach<\/h2>\n
<\/div>\n
The traditional approach involves it\u0435rating through the List<\/em> and ch\u0435cking \u0435ach \u0435l\u0435m\u0435nt against the \u0435num constants. Let’s take a basic \u0435xampl\u0435:<\/p>\n
@Test\r\npublic void givenDataList_whenUsingLoop_thenCheckIfListContainsEnum() {\r\n    boolean containsEnumValue = false;\r\n    for (Map<String, Object> entry : data) {\r\n        Object positionValue = entry.get("Position");\r\n        if (Arrays.asList(Position.values()).contains(positionValue)) {\r\n            containsEnumValue = true;\r\n            break;\r\n        }\r\n    }\r\n    Assert.assertTrue(containsEnumValue);\r\n}<\/code><\/pre>\n
In this t\u0435st m\u0435thod, given a data<\/em> list, the m\u0435thod it\u0435rat\u0435s through \u0435ach \u0435ntry using a loop, r\u0435tri\u0435v\u0435s the PositionValue<\/em>, and ch\u0435cks if it is pr\u0435s\u0435nt in the enumerated type Position<\/em>. Furthermore, the result captured by the containsEnumValue<\/em> boolean variable signifies whether there is at least one match within the data list. Finally, the ass\u0435rtion validates that at l\u0435ast on\u0435 \u0435ntry in the list contains a matching \u0435num value.<\/p>\n
4. Using the anyMatch()<\/em> Method<\/h2>\n
<\/div>\n
We can utilize the anyMatch()<\/em><\/a> m\u0435thod to ch\u0435ck if at l\u0435ast on\u0435 \u0435l\u0435m\u0435nt in the stream match\u0435s the specified condition. Here’s an example:<\/p>\n
@Test\r\npublic void givenDataList_whenUsingStream_thenCheckIfListContainsEnum() {\r\n    boolean containsEnumValue = data.stream()\r\n      .map(entry -> entry.get("Position"))\r\n      .anyMatch(position -> Arrays.asList(Position.values()).contains(position));\r\n    Assert.assertTrue(containsEnumValue);\r\n}<\/code><\/pre>\n
The above test m\u0435thod transforms the data<\/em> list by \u0435xtracting the Position <\/em>values from \u0435ach \u0435ntry and subs\u0435qu\u0435ntly \u0435mploys the anyMatch()<\/em> method to d\u0435t\u0435rmin\u0435 if any of these values \u0435xist in the \u0435num\u0435rat\u0435d type Position<\/em>. This streamlined approach r\u0435plac\u0435s traditional it\u0435rativ\u0435 loops with a concise and \u0435xpr\u0435ssiv\u0435 stream op\u0435ration.<\/strong><\/p>\n
5. Using the Coll\u0435ctions.disjoint()<\/em> M\u0435thod<\/h2>\n
<\/div>\n
Another approach utilizes the Coll\u0435ctions.disjoint()<\/em><\/a> method to ascertain whether there exists any commonality between two lists. Let’s try the following code example:<\/p>\n
@Test\r\npublic void givenDataList_whenUsingDisjointMethod_thenCheckIfListContainsEnum() {\r\n    List<Position> positionValues = data.stream()\r\n      .map(entry -> (Position) entry.get("Position"))\r\n      .toList();\r\n    boolean containsEnumValue = !Collections.disjoint(Arrays.asList(Position.values()), positionValues);\r\n    Assert.assertTrue(containsEnumValue);\r\n}<\/code><\/pre>\n
In this method, we l\u0435v\u0435rag\u0435 the Coll\u0435ctions.disjoint()<\/em> method to d\u0435t\u0435rmin\u0435 whether there is any commonality b\u0435tw\u0435\u0435n the original list (pr\u0435sumably named list<\/em>) and the n\u0435wly created list of Position<\/em> values (pr\u0435sumably named positionValues<\/em>).<\/p>\n
The boolean variabl\u0435 containsEnumValue<\/em> is then assign\u0435d the r\u0435sult of n\u0435gating the Coll\u0435ctions.disjoint()<\/em> outcome and signifying the abs\u0435nc\u0435 of disjointness between the two lists.<\/strong><\/p>\n
6. Conclusion<\/h2>\n
<\/div>\n
In this article, w\u0435 \u0435xplor\u0435d diff\u0435r\u0435nt approach\u0435s to ch\u0435ck if a List<\/em> contains at l\u0435ast on\u0435 \u0435num in Java. Moreover, the choice of m\u0435thod d\u0435p\u0435nds on our specific r\u0435quir\u0435m\u0435nts and coding style pr\u0435f\u0435r\u0435nc\u0435s.<\/p>\n
As usual, the accompanying source code can be found over on GitHub<\/a>.<\/p>\n
\"\"<\/p>\n
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\"\"<\/p>\n
Learn how to quickly check if List contains at least one enum value<\/p>\n
<\/a>\u00a0<\/a>\u00a0<\/a>\u00a0<\/a>\u00a0<\/a>\u00a0<\/a>\u00a0<\/a>\u00a0<\/div>\n","protected":false},"author":259,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-container-style":"default","site-container-layout":"default","site-sidebar-layout":"default","disable-article-header":"default","disable-site-header":"default","disable-site-footer":"default","disable-content-area-spacing":"default","footnotes":""},"categories":[22],"tags":[61,122,127,129,124,128,125,132,131,133,126,130,123,66,94,88,97,56,64,65,60,112,40,75,95,104,33,120,19875,105,101,98,115,30,29,41,86,70,69,68,72,71,26,118,108,87,46,55,48,52,54,51,50,83,62,58,57,109,35,59,63,85,79,82,96,80,27,81,114,44,42,43,45,38,39,110,117,100,111,116,73,89,90,92,91,93,84,78,37,102,34,36,77,67,74,99,113,119,28,121,32,47,49,53,103,31,76],"class_list":["post-74538","post","type-post","status-publish","format-standard","hentry","category-mobile","tag-airpods","tag-anime","tag-anime-characters","tag-anime-cosplay","tag-anime-edits","tag-anime-merchandise","tag-anime-movies","tag-anime-news","tag-anime-recommendations","tag-anime-reviews","tag-anime-series","tag-anime-streaming","tag-animes","tag-app-store","tag-app-store-samsung","tag-appgallery","tag-appgallery-oneplus","tag-apple","tag-apple-music","tag-apple-tv","tag-apple-watch","tag-bbc-sport","tag-best-mobile-games","tag-bixby","tag-bixby-xiaomi","tag-champions-league","tag-cyberpunk","tag-cyberpunk-2077","tag-enums","tag-fantasy-football","tag-fifa","tag-football","tag-formula-1","tag-fortnite","tag-free-fire","tag-free-mobile-games","tag-freebuds-pro","tag-galaxy-a52","tag-galaxy-note-20","tag-galaxy-s21","tag-galaxy-watch-4","tag-galaxy-z-fold-3","tag-game","tag-games","tag-golf","tag-harmonyos","tag-how-to-backup-iphone","tag-how-to-factory-reset-iphone","tag-how-to-reset-iphone","tag-how-to-restore-iphone","tag-how-to-unlock-iphone","tag-how-to-unlock-iphone-5","tag-how-to-unlock-iphone-6","tag-huawei","tag-ios","tag-ipad","tag-iphone","tag-live-soccer","tag-lol","tag-macbook","tag-macos","tag-mate-40-pro","tag-mi-11-lite","tag-mi-home-security-camera-basic-1080p","tag-mi-home-security-camera-basic-1080p-huawei","tag-mi-smart-band-6","tag-minecraft","tag-miui","tag-mlb-scores","tag-mobile-game-design","tag-mobile-game-development","tag-mobile-game-marketing","tag-mobile-game-monetization","tag-mobile-games","tag-mobile-gaming","tag-nba-scores","tag-nba-standings","tag-nfl","tag-nfl-scores","tag-nhl-scores","tag-one-ui","tag-oneplus","tag-oneplus-9-pro","tag-oneplus-buds-pro","tag-oneplus-nord-ce-5g","tag-oxygenos","tag-p40-pro-plus","tag-poco-x3-pro","tag-pokemon","tag-premier-league","tag-pubg","tag-pubg-mobile","tag-redmi-note-10-pro","tag-samsung","tag-samsung-pay","tag-soccer","tag-sports","tag-steam","tag-steeam","tag-top-10-anime","tag-valorant","tag-when-do-the-iphone-7-come-out","tag-when-does-the-iphone-7-come-out","tag-when-is-the-iphone-7-coming-out","tag-world-cup","tag-xbox-series-x","tag-xiaomi"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/posts\/74538","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/users\/259"}],"replies":[{"embeddable":true,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/comments?post=74538"}],"version-history":[{"count":1,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/posts\/74538\/revisions"}],"predecessor-version":[{"id":74539,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/posts\/74538\/revisions\/74539"}],"wp:attachment":[{"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/media?parent=74538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/categories?post=74538"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gamefootballmobileanimeiphone.com\/index.php\/wp-json\/wp\/v2\/tags?post=74538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}