GradleでJava 13のプレビュー機能を試す
GradleでJava 13のプレビュー機能を試したときのメモ。
Gradleは6.0以降を使用する。
Gradle 6.0 Release Notes
ソースコード
build.gradle
--enable-previewを設定する
plugins { id 'java' id 'application' } group 'com.example' version '1.0-SNAPSHOT' sourceCompatibility = JavaVersion.VERSION_13 repositories { mavenCentral() } tasks.withType(JavaCompile) { options.compilerArgs += ['--enable-preview'] } test { jvmArgs = ['--enable-preview'] } run { jvmArgs = ['--enable-preview'] } mainClassName = 'com.example.Main'
Main.java
今回はText BlocksとSwitch Expressionsを試す
JEP 368: Text Blocks (Second Preview)
JEP 361: Switch Expressions
package com.example; public class Main { public static void main(String... args) { String message = """ AAA BBB CCC """; System.out.println(message); System.out.println(isWeekend(DayOfWeek.FRIDAY)); System.out.println(isWeekend(DayOfWeek.SUNDAY)); } private static boolean isWeekend(DayOfWeek day) { return switch (day) { case SATURDAY, SUNDAY -> true; case MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY -> false; }; } }
実行結果
% ./gradlew run > Task :run AAA BBB CCC false true BUILD SUCCESSFUL in 470ms