Rules

Documentation Rules

All name acronym

While uppercase acronym does comply with pascal-case naming standards, lowercase acronym is easier to read. However, only 3 connecting uppercase letters are flagged. This rule affects property, function, class-alike and even file.

val userJSON = "{ user: \"Hendra Anggrian\" }"
fun blendARGB()
class RestAPI
SQLUtility.kt

Class body starting whitespace

If a class' declaration is multiline and has a content, the first line of the content should be an empty line. This rule affects all class-like objects (class, interface, etc.).

class User(
    username: String,
    password: String
) {
    override fun toString(): String = username
}

Functions return type

Prohibits declaration of public expression function and property accessor without return type.

fun getMessage() = "Hello World"
val message get() = "Hello World"

Throw exception ambiguity

Throwing Exception, Error, and Throwable require a detail message. Does not apply to their subtypes (IllegalStateExeption, StackOverflowError, etc.) as they are explicit enough.

throw Exception()

Types Kotlin API

Avoid using API from java.* and org.junit.* where there are Kotlin equivalents.

import java.lang.String
val images = java.util.ArrayList<Image>()

Summary continuation

Every new line of continuation paragraph cannot start with link or code.

/**
 * This is a superclass of all
 * [cars] and
 * `bikes`.
 */
interface Vehicle

This is a default behavior of markdown editor on IntelliJ IDEs.

Tag description sentence

Description of certain tags, if present, is in form of a sentence. Therefore, must have one of end punctuations ., !, or ?.

/**
 * @param message a simple text
 */
fun send(message: String)

Tags starting whitespace

Both Javadoc and Kdoc recommend putting an empty space separating summary and tag group.

/**
 * Insert an item to this collection.
 * @param element item to add.
 * @return true if element is successfully added.
 */
fun add(element: E): Boolean