😷 🕑 👨‍✈️ Java 15 dan IntelliJ IDEA 👨‍🍳 👎🏿 🚵

Java 15 memperkenalkan kelas tertutup dan antarmuka tertutup , dengan bantuan yang memungkinkan untuk membatasi hierarki kelas dan antarmuka pada tingkat sintaks bahasa. Kemungkinan hierarki sekarang didefinisikan secara deklaratif. Fungsionalitas ini masih disajikan dalam mode pratinjau .

Juga di Java 15, ada perubahan pada Records yang diperkenalkan di Java 14. Dan pencocokan pola untuk instanceof datang di Java 15 sebagai pratinjau kedua tidak berubah. Blok teks dari Java 13 disertakan dalam Java 15 sebagai konstruksi bahasa standar. Tidak ada perubahan di dalamnya dibandingkan dengan Java 14.

Dalam artikel ini, saya akan memandu Anda melalui semua konstruksi bahasa Java 15 yang baru dan yang diperbarui, bagaimana mereka dapat berguna bagi Anda, dan bagaimana menggunakannya di IntelliJ IDEA. Ayo mulai.

Kelas dan antarmuka tertutup

sealed, , . , , , — . ?

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class Plant {}
class Herb extends Plant {}
class Shrub extends Plant {}
class Climber extends Plant{}
class Cucumber extends Climber {}

, Gardener

() :

public class Gardener {
   int process(Plant plant) {
       if (plant instanceof Cucumber) {
           return harvestCucumber();
       } else if (plant instanceof Climber) {
           return sowClimber();
       } else if (plant instanceof Herb) {
           return sellHerb();
       } else if (plant instanceof Shrub) {
           return pruneShrub();
       } else {
           System.out.println("Unreachable CODE. Unknown Plant type");
           return 0;
       }
   }

   private int pruneShrub() { .. }
   private int sellHerb() { .. }
   private int sowClimber() { .. }
   private int harvestCucumber() { .. }
}

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sealed public class Plant permits Herb, Shrub, Climber {
}

final class Herb extends Plant {}
non-sealed class Shrub extends Plant {}
sealed class Climber extends Plant permits Cucumber{}

final class Cucumber extends Climber {}

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IntelliJ IDEA

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Java 15 IntelliJ IDEA. "Project Structure" "Platform Settings" "SDKs", "+" "Download JDK". (Vendor), (Version) JDK.

Plant Gardener

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:

//      Java 15.
//       Java 
//   type-test-pattern  switch 
int processInAFutureJavaVersion(Plant plant) {
   return switch (plant) {
       case Cucumber c -> c.harvestCucumber();
       case Climber cl -> cl.sowClimber();
       case Herb h -> h.sellHerb();
       case Shrub s -> s.pruneShrub();
   }
}

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grow()

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grow()

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grow()

:

sealed abstract public class Plant permits Herb, Shrub, Climber {
   abstract void grow();
}
final class Herb extends Plant {
   @Override
   void grow() {
   }
}
non-sealed abstract class Shrub extends Plant {}
sealed class Climber extends Plant permits Cucumber{
   @Override
   void grow() {
   }
}
final class Cucumber extends Climber {}

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sealed public interface Move permits Athlete, Person, Jump, Kick {
}
final class Athlete implements Move {}
record Person(String name, int age) implements Move {}
non-sealed interface Jump extends Move {}
sealed interface Kick extends Move permits Karate {}
final class Karate implements Kick {}

Java 15 – (record).

(records)

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Java 15 Java 14.

Java 15 . getTopPerformingStocks()

(stock), , .

List<String> getTopPerformingStocks(List<Stock> allStocks, LocalDate date) {
   // TopStock -   (Record)
   record TopStock(Stock stock, double stockValue) {}
   return allStocks.stream()
              .map(s -> new TopStock(s, getStockValue(s, date)))
              .sorted((s1, s2) -> Double.compare(s1.stockValue(), s2.stockValue()))
              .limit(2)
              .map(s -> s.stock.getName())
              .collect(Collectors.toList());
}

Java 15 . -.

public void createLocalInterface() {
   interface LocalInterface {
       void aMethod();
   }
   // ,  LocalInterface
}

public void createLocalEnum() {
   enum Color {RED, YELLOW, BLUE}
   // ,  enum Color
}

. , FOO

BAR

:

void test(int input) {
   enum Data {
       FOO(input), BAR(input*2); // .    input
       private final int i;
       Data(int i) {
           this.i = i;
       }
   }
}

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. IntelliJ IDEA.

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Java 15 dan IntelliJ IDEA