{"id":4630,"date":"2019-10-21T00:55:50","date_gmt":"2019-10-20T15:55:50","guid":{"rendered":"https:\/\/chat-messenger.com\/?p=4630"},"modified":"2023-11-13T01:14:20","modified_gmt":"2023-11-12T16:14:20","slug":"contoh-java","status":"publish","type":"post","link":"https:\/\/chat-messenger.com\/id\/blog\/java\/java-instanceof","title":{"rendered":"Java \u5909\u6570\u306e\u578b\u3092 instanceof \u3067\u78ba\u8a8d\u3059\u308b"},"content":{"rendered":"

Periksa tipe variabelnya.<\/h2>\n\n\n\n

Program contoh ini menunjukkan cara memeriksa tipe variabel di Java.<\/p>\n\n\n\n

Java adalah bahasa pemrograman bertipe statis di mana tipe data dideklarasikan secara eksplisit, sehingga tidak banyak kesempatan untuk memeriksa tipe data. Namun, ketika menggunakan objek yang diwariskan, pemeriksaan tipe data mungkin menjadi perlu.<\/p>\n\n\n\n

Cara memeriksa tipe data di Java instanceof<\/strong> Anda dapat menggunakan operator untuk mengevaluasi kelas dan antarmuka menggunakan pernyataan if, seperti berikut:<\/p>\n\n\n\n

\n

variabel<\/em> instanceof \u30af\u30e9\u30b9<\/p>\n\n\n\n

variabel<\/em> instanceof \u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9<\/p>\n<\/div><\/div>\n\n\n\n

instanceof<\/strong> Anda dapat menentukan nama kelas atau nama antarmuka di sisi kanan.instanceof<\/strong> Nilai kembaliannya adalah boolean, dan jika bernilai true, variabel tersebut adalah kelas atau antarmuka yang ditentukan.<\/p>\n\n\n\n

\n

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Contoh program<\/h2>\n\n\n\n

Mari kita mulai dengan pola yang paling sederhana. Jika variabel i adalah bilangan bulat, maka akan mengembalikan nilai true; jika tidak, akan mengembalikan nilai false.<\/p>\n\n\n\n

Contoh kode<\/h4>\n\n\n\n
public static void integerSample() {\n    Integer i = 100;\n    boolean result = i instanceof Integer;\n    System.out.println(result);\n}<\/code><\/pre><\/div>\n\n\n\n
Hasil keluaran<\/h4>\n\n\n\n
true<\/code><\/pre><\/div>\n\n\n\n
\u5909\u6570 i \u306f Integer \u306a\u306e\u3067\u3001\u7d50\u679c\u306f true \u306b\u306a\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u3053\u308c\u3067\u306f\u5f53\u305f\u308a\u524d\u3059\u304e\u3066 instanceof \u304c\u306a\u3093\u306e\u305f\u3081\u306b\u3042\u308b\u304b\u5206\u304b\u306a\u3044\u306e\u3067\u3001\u3082\u3046\u5c11\u3057\u8907\u96d1\u306b\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
instanceof \u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9<\/h2>\n\n\n\n
instanceof \u306e\u52b9\u679c\u7684\u306a\u4f7f\u3044\u65b9\u306e\u4e00\u3064\u306b\u3001\u305d\u306e\u5909\u6570\u304c\u3069\u306e\u5b50\u30af\u30e9\u30b9\u306a\u306e\u304b\u3092\u5224\u5b9a\u3059\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
Contoh kode<\/h4>\n\n\n\n
Kode contoh tersebut membuat kelas hewan bernama Animal, dan dua kelas, Dog dan Cat, yang mewarisi dari kelas Animal. Setelah membuat instance, metode `play` digunakan untuk mendefinisikan variabel. instanceof<\/strong> Sistem menentukan hal ini dan mengarahkan output konsol sesuai dengan itu. <\/p>\n\n\n\n
class Animal {} \nclass Dog extends Animal {}\nclass Cat extends Animal {}\n\npublic class Main {\n    public static void main(String[] args) {\n        instanceofSample();\n    }\n    \n    static void instanceofSample() {\n        Animal dog = new Dog();\n        play(dog);\n        Animal cat = new Cat();\n        play(cat);\n    }\n    \n    static void play(Animal animal) {\n        if (animal instanceof Dog) {\n            System.out.println("\u304a\u6563\u6b69\u3059\u308b");\n        } else {\n            System.out.println("\u732b\u3058\u3083\u3089\u3057\u3067\u904a\u3076");\n        }\n    }\n}<\/code><\/pre><\/div>\n\n\n\n
Hasil keluaran<\/h4>\n\n\n\n
\u304a\u6563\u6b69\u3059\u308b\n\u732b\u3058\u3083\u3089\u3057\u3067\u904a\u3076<\/code><\/pre><\/div>\n\n\n\n
Intinya adalah, di dalam metode `play`, tidak mungkin untuk mengetahui apakah `animal` yang diberikan sebagai argumen adalah anjing atau kucing.<\/p>\n\n\n\n
instanceof<\/strong> Jadi, karena kita juga dapat memeriksa instance dari subkelas (Anjing atau Kucing) yang terdapat di dalam superkelas (Hewan), kita dapat menggunakannya dengan cara ini juga.<\/p>\n\n\n\n
Periksa apakah antarmuka tertentu telah diimplementasikan.<\/h2>\n\n\n\n
instanceof \u306e\u5bfe\u8c61\u3068\u306a\u308b\u5909\u6570\u306b\u3001\u3042\u308b\u7279\u5b9a\u306e\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u304c\u5b9f\u88c5\u3055\u308c\u3066\u3044\u308b\u304b\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002\u4f8b\u3048\u3070\u3053\u306e\u3088\u3046\u306a\u4f7f\u3044\u65b9\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
Contoh kode<\/h4>\n\n\n\n
\u6b21\u306e\u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9\u3067\u306f\u3001\u4f50\u85e4\u3055\u3093\u3001\u9234\u6728\u3055\u3093\u30af\u30e9\u30b9\u3092\u4f5c\u6210\u3057\u3001\u9234\u6728\u3055\u3093\u3060\u3051\u304c\u8eca\u3092\u6301\u3063\u3066\u3044\u308b\u60f3\u5b9a\u3067\u3001\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9 Car \u3092 implements \u3057\u3066\u3044\u307e\u3059\u3002goShopping() \u30e1\u30bd\u30c3\u30c9\u306f\u8cb7\u3044\u7269\u306b\u884c\u304f\u51e6\u7406\u3092\u4eee\u5b9a\u3057\u3066\u3044\u307e\u3059\u304c\u3001Car \u3092 implements \u3057\u3066\u3044\u308b\u304b\u3001instanceof \u3067\u5224\u5b9a\u3057\u3066\u30b3\u30f3\u30bd\u30fc\u30eb\u51fa\u529b\u3092\u5206\u5c90\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
interface Car {}\nclass Sato {}\nclass Suzuki implements Car {}\n\npublic class Main {\n    public static void main(String[] args) throws Exception {\n        instanceofSample();\n    }\n    \n    static void instanceofSample() {\n        Sato sato = new Sato();\n        goShopping(sato);\n\n        Suzuki suzuki = new Suzuki();\n        goShopping(suzuki);\n    }\n    \n    static void goShopping(Object human) {\n        if (human instanceof Car) {\n            System.out.println("\u8eca\u3067\u884c\u304f");\n        } else {\n            System.out.println("\u6b69\u3044\u3066\u884c\u304f");\n        }\n    }\n}<\/code><\/pre><\/div>\n\n\n\n
Hasil keluaran:<\/h4>\n\n\n\n
\u6b69\u3044\u3066\u884c\u304f\n\u8eca\u3067\u884c\u304f<\/code><\/pre><\/div>\n\n\n\n
Anda dapat melihat bahwa proses bercabang tergantung pada apakah Car diimplementasikan atau tidak.<\/p>","protected":false},"excerpt":{"rendered":"
\u5909\u6570\u306e\u578b\u3092\u78ba\u8a8d\u3059\u308b Java \u3067\u5909\u6570\u306e\u578b\u3092\u78ba\u8a8d\u3059\u308b\u30b5\u30f3\u30d7\u30eb\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002 Java \u306f\u578b\u3092\u660e\u793a\u7684\u306b\u5ba3 […]<\/p>\n","protected":false},"author":1,"featured_media":9054,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"swell_btn_cv_data":"","footnotes":""},"categories":[19],"tags":[],"class_list":["post-4630","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/posts\/4630","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/comments?post=4630"}],"version-history":[{"count":6,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/posts\/4630\/revisions"}],"predecessor-version":[{"id":9049,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/posts\/4630\/revisions\/9049"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/media\/9054"}],"wp:attachment":[{"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/media?parent=4630"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/categories?post=4630"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chat-messenger.com\/id\/wp-json\/wp\/v2\/tags?post=4630"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}