Dokka is a documentation engine for Kotlin, performing the same function as javadoc for Java. Just like Kotlin itself, Dokka fully supports mixed-language Java/Kotlin projects. It understands standard Javadoc comments in Java files and KDoc comments in Kotlin files, and can generate documentation in multiple formats including standard Javadoc, HTML and Markdown.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "org.jetbrains.dokka:dokka-gradle-plugin:${dokka_version}"
}
}
repositories {
jcenter() // or maven { url 'https://dl.bintray.com/kotlin/dokka' }
}
apply plugin: 'org.jetbrains.dokka'
or using the plugins block:
plugins {
id 'org.jetbrains.dokka' version '0.10.1'
}
repositories {
jcenter() // or maven { url 'https://dl.bintray.com/kotlin/dokka' }
}
The plugin adds a task named dokka
to the project.
If you encounter any problems when migrating from older versions of Dokka, please see the FAQ.
Minimal dokka configuration:
Groovy
dokka {
outputFormat = 'html'
outputDirectory = "$buildDir/dokka"
}
Kotlin
tasks {
val dokka by getting(DokkaTask::class) {
outputFormat = "html"
outputDirectory = "$buildDir/dokka"
}
}
The available configuration options for single platform are shown below:
dokka {
outputFormat = 'html'
outputDirectory = "$buildDir/javadoc"
// In case of a Gradle multiproject build, you can include subprojects here to get merged documentation
// Note however, that you have to have the Kotlin plugin available in the root project and in the subprojects
subProjects = ["subproject1", "subproject2"]
// Used for disabling auto extraction of sources and platforms in both multi-platform and single-platform modes
// When set to true, subProject and kotlinTasks are also omitted
disableAutoconfiguration = false
// Use default or set to custom path to cache directory
// to enable package-list caching
// When this is set to default, caches are stored in $USER_HOME/.cache/dokka
cacheRoot = 'default'
configuration {
moduleName = 'data'
// Use to include or exclude non public members.
includeNonPublic = false
// Do not output deprecated members. Applies globally, can be overridden by packageOptions
skipDeprecated = false
// Emit warnings about not documented members. Applies globally, also can be overridden by packageOptions
reportUndocumented = true
// Do not create index pages for empty packages
skipEmptyPackages = true
// This is a list of platform names that will be shown in the final result. See the "Platforms" section of this readme
targets = ["JVM"]
// Platform used for code analysis. See the "Platforms" section of this readme
platform = "JVM"
// Property used for manual addition of files to the classpath
// This property does not override the classpath collected automatically but appends to it
classpath = [new File("$buildDir/other.jar")]
// List of files with module and package documentation
// https://kotlinlang.org/docs/reference/kotlin-doc.html#module-and-package-documentation
includes = ['packages.md', 'extra.md']
// List of files or directories containing sample code (referenced with @sample tags)
samples = ['samples/basic.kt', 'samples/advanced.kt']
// By default, sourceRoots are taken from Kotlin Plugin, subProjects and kotlinTasks, following roots will be appended to them
// Full form sourceRoot declaration
// Repeat for multiple sourceRoots
sourceRoot {
// Path to a source root
path = "src"
}
// These tasks will be used to determine source directories and classpath
kotlinTasks {
defaultKotlinTasks() + [':some:otherCompileKotlin', project("another").compileKotlin]
}
// Specifies the location of the project source code on the Web.
// If provided, Dokka generates "source" links for each declaration.
// Repeat for multiple mappings
sourceLink {
// Unix based directory relative path to the root of the project (where you execute gradle respectively).
path = "src/main/kotlin" // or simply "./"
// URL showing where the source code can be accessed through the web browser
url = "https://github.com/cy6erGn0m/vertx3-lang-kotlin/blob/master/src/main/kotlin" //remove src/main/kotlin if you use "./" above
// Suffix which is used to append the line number to the URL. Use #L for GitHub
lineSuffix = "#L"
}
// Used for linking to JDK documentation
jdkVersion = 6
// Disable linking to online kotlin-stdlib documentation
noStdlibLink = false
// Disable linking to online JDK documentation
noJdkLink = false
// Allows linking to documentation of the project's dependencies (generated with Javadoc or Dokka)
// Repeat for multiple links
externalDocumentationLink {
// Root URL of the generated documentation to link with. The trailing slash is required!
url = new URL("https://example.com/docs/")
// If package-list file is located in non-standard location
// packageListUrl = new URL("file:///home/user/localdocs/package-list")
}
// Allows to customize documentation generation options on a per-package basis
// Repeat for multiple packageOptions
perPackageOption {
prefix = "kotlin" // will match kotlin and all sub-packages of it
// All options are optional, default values are below:
skipDeprecated = false
reportUndocumented = true // Emit warnings about not documented members
includeNonPublic = false
}
// Suppress a package
perPackageOption {
prefix = "kotlin.internal" // will match kotlin.internal and all sub-packages of it
suppress = true
}
}
}
Since version 0.10.0 dokka supports multiplatform projects. For a general understanding how a multiplatform documentation is generated, please consult the FAQ.
In the multiplatform mode, instead of using the configuration
block, you should use a multiplatform
block with inner blocks for each platform.
The configuration
block's parameters belong to those inner blocks, which can be named arbitrarly, however if you want to use source roots and classpath provided by Kotlin Multiplatform plugin,
they must have the same names as in the Kotlin Multiplatform plugin. See an example below:
Groovy
kotlin { // Kotlin Multiplatform plugin configuration
jvm()
js("customName") // Define a js platform named "customName" If you want to generate docs for it, you need to have this name in dokka configuration below
}
dokka {
outputDirectory = "$buildDir/dokka"
outputFormat = "html"
multiplatform {
customName { // The same name as in Kotlin Multiplatform plugin, so the sources are fetched automatically
includes = ['packages.md', 'extra.md']
samples = ['samples/basic.kt', 'samples/advanced.kt']
}
differentName { // Different name, so source roots, classpath and platform must be passed explicitly.
targets = ["JVM"]
platform = "jvm"
sourceRoot {
path = kotlin.sourceSets.jvmMain.kotlin.srcDirs[0]
}
sourceRoot {
path = kotlin.sourceSets.commonMain.kotlin.srcDirs[0]
}
}
}
}
Kotlin
kotlin { // Kotlin Multiplatform plugin configuration
jvm()
js("customName")
}
val dokka by getting(DokkaTask::class) {
outputDirectory = "$buildDir/dokka"
outputFormat = "html"
multiplatform {
val customName by creating { // The same name as in Kotlin Multiplatform plugin, so the sources are fetched automatically
includes = listOf("packages.md", "extra.md")
samples = listOf("samples/basic.kt", "samples/advanced.kt")
}
register("differentName") { // Different name, so source roots must be passed explicitly
targets = listOf("JVM")
platform = "jvm"
sourceRoot {
path = kotlin.sourceSets.getByName("jvmMain").kotlin.srcDirs.first().toString()
}
sourceRoot {
path = kotlin.sourceSets.getByName("commonMain").kotlin.srcDirs.first().toString()
}
}
}
}
For convenience, there is also a reserved block called global
, which is a top-level configuration of perPackageOptions
, externalDocumentationLinks
, and sourceLinks
shared by every platform. Eg.
dokka {
multiplatform {
global { // perPackageOptions, sourceLinks and externalDocumentationLinks from here will be copied to every other platform (jvm and js in eg.)
perPackageOption {
prefix = "com.somePackage"
suppress = true
}
perPackageOption { // You can repeat this block for multiple perPackageOptions
prefix = "kotlin"
skipDeprecated = false
reportUndocumented = true
includeNonPublic = false
}
sourceLink {
path = "src/main/kotlin"
url = "https://github.com/cy6erGn0m/vertx3-lang-kotlin/blob/master/src/main/kotlin"
lineSuffix = "#L"
}
externalDocumentationLink {
url = new URL("https://example.com/docs/")
}
}
js {}
jvm {}
}
}
The parameters from the global
block are appended to all the other platform configurations (in the example - js
and jvm
) and cannot be overriden.
Note that javadoc
output format cannot be used with multiplatform.
To generate the documentation, use the dokka
Gradle task:
./gradlew dokka
More dokka tasks can be added to a project like this:
task dokkaMarkdown(type: org.jetbrains.dokka.gradle.DokkaTask) {
outputFormat = 'markdown'
outputDirectory = "$buildDir/markdown"
}
Please see the Dokka Gradle example project for an example.
If you are using Gradle plugin and you want to use a custom version of dokka, you can do it by setting dokkaRuntime
configuration:
buildscript {
...
}
apply plugin: 'org.jetbrains.dokka'
repositories {
jcenter()
}
dependencies {
dokkaRuntime "org.jetbrains.dokka:dokka-fatjar:0.10.1"
}
dokka {
outputFormat = 'html'
outputDirectory = "$buildDir/dokkaHtml"
}
To use your Fat Jar, just set the path to it:
buildscript {
...
}
apply plugin: 'org.jetbrains.dokka'
repositories {
jcenter()
}
dependencies {
dokkaRuntime files("/path/to/fatjar/dokka-fatjar-0.10.1.jar")
}
dokka {
outputFormat = 'html'
outputDirectory = "$buildDir/dokkaHtml"
}
If you encounter any problems, please see the FAQ.
Since version 0.10.0 the separate Android plugin is merged with the default one.
Just make sure you apply the plugin after
com.android.library
and kotlin-android
.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "org.jetbrains.dokka:dokka-gradle-plugin:${dokka_version}"
}
}
repositories {
jcenter()
}
apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'org.jetbrains.dokka'
There is also a noAndroidSdkLink
configuration parameter that works similar to noJdkLink
and noStdlibLink
By default the variant documented by dokka is the first release variant encountered.
You can override that by setting the androidVariants
property inside the configuration
(or specific platform) block:
dokka {
configuration {
androidVariants = ["debug", "release"]
}
}
The Maven plugin does not support multiplatform projects.
The Maven plugin is available in JCenter. You need to add the JCenter repository to the list of plugin repositories if it's not there:
<pluginRepositories>
<pluginRepository>
<id>jcenter</id>
<name>JCenter</name>
<url>https://jcenter.bintray.com/</url>
</pluginRepository>
</pluginRepositories>
Minimal Maven configuration is
<plugin>
<groupId>org.jetbrains.dokka</groupId>
<artifactId>dokka-maven-plugin</artifactId>
<version>${dokka.version}</version>
<executions>
<execution>
<phase>pre-site</phase>
<goals>
<goal>dokka</goal>
</goals>
</execution>
</executions>
</plugin>
By default files will be generated in target/dokka
.
The following goals are provided by the plugin:
dokka:dokka
- generate HTML documentation in Dokka format (showing declarations in Kotlin syntax);dokka:javadoc
- generate HTML documentation in JavaDoc format (showing declarations in Java syntax);dokka:javadocJar
- generate a .jar file with JavaDoc format documentation.
The available configuration options are shown below:
<plugin>
<groupId>org.jetbrains.dokka</groupId>
<artifactId>dokka-maven-plugin</artifactId>
<version>${dokka.version}</version>
<executions>
<execution>
<phase>pre-site</phase>
<goals>
<goal>dokka</goal>
</goals>
</execution>
</executions>
<configuration>
<!-- Set to true to skip dokka task, default: false -->
<skip>false</skip>
<!-- Default: ${project.artifactId} -->
<moduleName>data</moduleName>
<!-- See list of possible formats below -->
<outputFormat>html</outputFormat>
<!-- Default: ${project.basedir}/target/dokka -->
<outputDir>some/out/dir</outputDir>
<!-- Use default or set to custom path to cache directory to enable package-list caching. -->
<!-- When set to default, caches stored in $USER_HOME/.cache/dokka -->
<cacheRoot>default</cacheRoot>
<!-- List of '.md' files with package and module docs -->
<!-- https://kotlinlang.org/docs/reference/kotlin-doc.html#module-and-package-documentation -->
<includes>
<include>packages.md</include>
<include>extra.md</include>
</includes>
<!-- List of sample roots -->
<samples>
<dir>src/test/samples</dir>
</samples>
<!-- Used for linking to JDK, default: 6 -->
<jdkVersion>6</jdkVersion>
<!-- Do not output deprecated members, applies globally, can be overridden by packageOptions -->
<skipDeprecated>false</skipDeprecated>
<!-- Emit warnings about not documented members, applies globally, also can be overridden by packageOptions -->
<reportUndocumented>true</reportUndocumented>
<!-- Do not create index pages for empty packages -->
<skipEmptyPackages>true</skipEmptyPackages>
<!-- Short form list of sourceRoots, by default, set to ${project.compileSourceRoots} -->
<sourceDirectories>
<dir>src/main/kotlin</dir>
</sourceDirectories>
<!-- Full form list of sourceRoots -->
<sourceRoots>
<root>
<path>src/main/kotlin</path>
<!-- See platforms section of documentation -->
<platforms>JVM</platforms>
</root>
</sourceRoots>
<!-- Specifies the location of the project source code on the Web. If provided, Dokka generates "source" links
for each declaration. -->
<sourceLinks>
<link>
<!-- Source directory -->
<path>${project.basedir}/src/main/kotlin</path>
<!-- URL showing where the source code can be accessed through the web browser -->
<url>https://github.com/cy6erGn0m/vertx3-lang-kotlin/blob/master/src/main/kotlin</url> <!-- //remove src/main/kotlin if you use "./" above -->
<!--Suffix which is used to append the line number to the URL. Use #L for GitHub -->
<lineSuffix>#L</lineSuffix>
</link>
</sourceLinks>
<!-- Disable linking to online kotlin-stdlib documentation -->
<noStdlibLink>false</noStdlibLink>
<!-- Disable linking to online JDK documentation -->
<noJdkLink>false</noJdkLink>
<!-- Allows linking to documentation of the project's dependencies (generated with Javadoc or Dokka) -->
<externalDocumentationLinks>
<link>
<!-- Root URL of the generated documentation to link with. The trailing slash is required! -->
<url>https://example.com/docs/</url>
<!-- If package-list file located in non-standard location -->
<!-- <packageListUrl>file:///home/user/localdocs/package-list</packageListUrl> -->
</link>
</externalDocumentationLinks>
<!-- Allows to customize documentation generation options on a per-package basis -->
<perPackageOptions>
<packageOptions>
<!-- Will match kotlin and all sub-packages of it -->
<prefix>kotlin</prefix>
<!-- All options are optional, default values are below: -->
<skipDeprecated>false</skipDeprecated>
<!-- Emit warnings about not documented members -->
<reportUndocumented>true</reportUndocumented>
<includeNonPublic>false</includeNonPublic>
</packageOptions>
</perPackageOptions>
</configuration>
</plugin>
Please see the Dokka Maven example project for an example.
The Ant task definition is also contained in the dokka-fatjar.jar referenced above. Here's an example usage:
<project name="Dokka" default="document">
<typedef resource="dokka-antlib.xml" classpath="dokka-fatjar.jar"/>
<target name="document">
<dokka format="html" outputDir="doc"/>
</target>
</project>
The Ant task supports the following attributes:
outputDir
- the output directory where the documentation is generatedformat
- the output format (see the list of supported formats below)cacheRoot
- Usedefault
or set to custom path to cache directory to enable package-list caching. When set todefault
, caches stored in $USER_HOME/.cache/dokka
Inside the dokka
tag you can create another tags named <passconfig/>
that support the following attributes:
classpath
- list of directories or .jar files to include in the classpath (used for resolving references)samples
- list of directories containing sample code (documentation for those directories is not generated but declarations from them can be referenced using the@sample
tag)moduleName
- the name of the module being documented (used as the root directory of the generated documentation)include
- names of files containing the documentation for the module and individual packagesskipDeprecated
- if set, deprecated elements are not included in the generated documentationjdkVersion
- version for linking to JDKanalysisPlatform="jvm"
- platform used for analysing sourceRoots, see the platforms section<sourceRoot path="src" />
- source root<packageOptions prefix="kotlin" includeNonPublic="false" reportUndocumented="true" skipDeprecated="false"/>
- Per package options for packagekotlin
and sub-packages of itnoStdlibLink
- disable linking to online kotlin-stdlib documentationnoJdkLink
- disable linking to online JDK documentation<externalDocumentationLink url="https://example.com/docs/" packageListUrl="file:///home/user/localdocs/package-list"/>
- linking to external documentation, packageListUrl should be used if package-list located not in standard location<target value="JVM"/>
- see the platforms section
To run Dokka from the command line, download the Dokka jar. To generate documentation, run the following command:
java -jar dokka-fatjar.jar <arguments>
Dokka supports the following command line arguments:
-output
- the output directory where the documentation is generated-format
- the output format:-cacheRoot
- usedefault
or set to custom path to cache directory to enable package-list caching. When set todefault
, caches stored in $USER_HOME/.cache/dokka-pass
- (repeatable) - configuration for single analyser pass. Following this argument, you can pass other arguments:-src
- (repeatable) - source file or directory (allows many paths separated by the system path separator)-classpath
- (repeatable) - directory or .jar file to include in the classpath (used for resolving references)-sample
- (repeatable) - directory containing a sample code (documentation for those directories is not generated but declarations from them can be referenced using the@sample
tag)-module
- the name of the module being documented (used as the root directory of the generated documentation)-include
- (repeatable) - names of files containing the documentation for the module and individual packages-skipDeprecated
- if set, deprecated elements are not included in the generated documentation-reportUndocumented
- warn about undocumented members-skipEmptyPackages
- do not create index pages for empty packages-packageOptions
- list of package options in formatprefix,-deprecated,-privateApi,+warnUndocumented;prefix, ...
-links
- external documentation links in formaturl^packageListUrl^^url2...
-srcLink
- (repeatable) - mapping between a source directory and a Web site for browsing the code in format<path>=<url>[#lineSuffix]
-noStdlibLink
- disable linking to online kotlin-stdlib documentation-noJdkLink
- disable linking to online JDK documentation-jdkVersion
- version of JDK to use for linking to JDK JavaDoc-analysisPlatform
- platform used for analysis, see the Platforms section-target
- (repeatable) - generation target
html
- minimalistic html format used by default, Java classes are translated to Kotlinjavadoc
- looks like normal Javadoc, Kotlin classes are translated to Javahtml-as-java
- looks likehtml
, but Kotlin classes are translated to Javamarkdown
- markdown structured ashtml
, Java classes are translated to Kotlingfm
- GitHub flavored markdownjekyll
- Jekyll compatible markdown
kotlin-website*
- internal format used for documentation on kotlinlang.org
Dokka can annotate elements with special platform
block with platform requirements
Example result and usage can be found on kotlinlang.org
Each multiplatform closure has two properties: platform
and targets
. If you use autoconfiguration, those are filled automatically.
targets
property is a list of platform names that will be shown in the final result. Note that the value of this property
doesn't affect analysis of source code, it just changes the result. You can think of this as a name
property
platform
property is used for the analysis of source roots. Available values are:
jvm
js
native
common