A set of scope functions for Java.

• What is JLet
• How to use
• Functions
  • let
  • test
  • run
  • with
  • it
• Checked exceptions
• Contributors
• Licence

JLet is a set of scope functions for Java, similar to Kotlin's scope functions but Java-specific.

When you call a scope function with an object and a lambda expression, it forms a temporary scope. In this scope, you can access the object as a lambda expression argument.

Requires Java 8+ version.

Maven:

<dependencies> <dependency> <groupId>dev.jlet</groupId> <artifactId>jlet</artifactId> <version>1.0</version> </dependency> </dependencies>

Gradle (Groovy):

dependencies { implementation 'dev.jlet:jlet:1.0' }

Gradle (Kotlin):

dependencies { implementation("dev.jlet:jlet:1.0") }

• has value arguments (from 1 to 8)
• has result (lambda expression result)

String shortString = let(someObject.toString(), s -> s.length() > 10 ? s.substring(0, 11) : s );

• has value arguments (from 0 to 8)
• has result (lambda expression boolean result)

if (test(someObject.toString(), s -> s.length() > 10 && s.contains("."))) { System.out.println("OK"); }

• has no value arguments
• has no result

run(() -> { String localVariable1 = "string1"; String localVariable2 = "string2"; System.out.println(localVariable1); System.out.println(localVariable2); });

• has value arguments (from 1 to 8)
• has no result

with(someObject.toString(), s -> { String shortString = s.length() > 10 ? s.substring(0, 11) : s; System.out.println(shortString); });

There are two options

• has no value arguments
• has result (lambda expression result)

someObject.setString(it(() -> { // calculations return "string"; }));

• has value arguments (from 1 to 8)
• has result (the first value argument)

someObject.setMap(it(new HashMap<>(), m -> { m.put(1, "first"); m.put(2, "second"); }));

All of these functions allow not catching checked exceptions.

static void throwingMethod() throws Throwable { throw new Throwable(); } static void method() { run(() -> throwingMethod()); }

• @evpl as Evgenii Plugatar

JLet is open-source project, and distributed under the MIT license.