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19 KiB
19 KiB
dokka
Note: This is Google's fork of Dokka, customized for Android API reference docs on developer.android.com and other Google products.
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.
Using Dokka
Using the Gradle plugin
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "org.jetbrains.dokka:dokka-gradle-plugin:${dokka_version}"
}
}
apply plugin: 'org.jetbrains.dokka'
The plugin adds a task named "dokka" to the project.
Minimal dokka configuration:
dokka {
outputFormat = 'html'
outputDirectory = "$buildDir/javadoc"
}
The available configuration options are shown below:
dokka {
moduleName = 'data'
outputFormat = 'html'
outputDirectory = "$buildDir/javadoc"
// These tasks will be used to determine source directories and classpath
kotlinTasks {
defaultKotlinTasks() + [':some:otherCompileKotlin', project("another").compileKotlin]
}
// List of files with module and package documentation
// http://kotlinlang.org/docs/reference/kotlin-doc.html#module-and-package-documentation
includes = ['packages.md', 'extra.md']
// The list of files or directories containing sample code (referenced with @sample tags)
samples = ['samples/basic.kt', 'samples/advanced.kt']
jdkVersion = 6 // Used for linking to JDK
// Use default or set to custom path to cache directory
// to enable package-list caching
// When set to default, caches stored in $USER_HOME/.cache/dokka
cacheRoot = 'default'
// Use to include or exclude non public members.
includeNonPublic = false
// Do not output deprecated members. Applies globally, can be overridden by packageOptions
skipDeprecated = false
// Emit warnings about not documented members. Applies globally, also can be overridden by packageOptions
reportUndocumented = true
skipEmptyPackages = true // Do not create index pages for empty packages
impliedPlatforms = ["JVM"] // See platforms section of documentation
// Manual adding files to classpath
// This property not overrides classpath collected from kotlinTasks but appends to it
classpath = [new File("$buildDir/other.jar")]
// By default, sourceRoots is taken from kotlinTasks, following roots will be appended to it
// Short form sourceRoots
sourceDirs = files('src/main/kotlin')
// By default, sourceRoots is taken from kotlinTasks, following roots will be appended to it
// Full form sourceRoot declaration
// Repeat for multiple sourceRoots
sourceRoot {
// Path to source root
path = "src"
// See platforms section of documentation
platforms = ["JVM"]
}
// Specifies the location of the project source code on the Web.
// If provided, Dokka generates "source" links for each declaration.
// Repeat for multiple mappings
linkMapping {
// Source directory
dir = "src/main/kotlin"
// 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"
// Suffix which is used to append the line number to the URL. Use #L for GitHub
suffix = "#L"
}
// No default documentation link to kotlin-stdlib
noStdlibLink = 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 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
packageOptions {
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
packageOptions {
prefix = "kotlin.internal" // will match kotlin.internal and all sub-packages of it
suppress = true
}
}
To generate the documentation, use the dokka Gradle task:
./gradlew dokka
More dokka tasks can be added to a project like this:
task dokkaJavadoc(type: org.jetbrains.dokka.gradle.DokkaTask) {
outputFormat = 'javadoc'
outputDirectory = "$buildDir/javadoc"
}
Please see the Dokka Gradle example project for an example.
Android
If you are using Android there is a separate Gradle plugin. Just make sure you apply the plugin after
com.android.library and kotlin-android.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "org.jetbrains.dokka:dokka-android-gradle-plugin:${dokka_version}"
}
}
apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'org.jetbrains.dokka-android'
Using the Maven plugin
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 -->
<!-- http://kotlinlang.org/docs/reference/kotlin-doc.html#module-and-package-documentation -->
<includes>
<file>packages.md</file>
<file>extra.md</file>
</includes>
<!-- List of sample roots -->
<samplesDirs>
<dir>src/test/samples</dir>
</samplesDirs>
<!-- 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 -->
<reportNotDocumented>true</reportNotDocumented>
<!-- Do not create index pages for empty packages -->
<skipEmptyPackages>true</skipEmptyPackages>
<!-- See platforms section of documentation -->
<impliedPlatforms>
<platform>JVM</platform>
</impliedPlatforms>
<!-- Short form list of sourceRoots, by default, set to ${project.compileSourceRoots} -->
<sourceDirectories>
<dir>src/main/kotlin</dir>
</sourceDirectories>
<!-- Full form list of sourceRoots -->
<sourceRoots>
<root>
<path>src/main/kotlin</path>
<!-- See platforms section of documentation -->
<platforms>JVM</platforms>
</root>
</sourceRoots>
<!-- Specifies the location of the project source code on the Web. If provided, Dokka generates "source" links
for each declaration. -->
<sourceLinks>
<link>
<!-- Source directory -->
<dir>${project.basedir}/src/main/kotlin</dir>
<!-- URL showing where the source code can be accessed through the web browser -->
<url>http://github.com/me/myrepo</url>
<!--Suffix which is used to append the line number to the URL. Use #L for GitHub -->
<urlSuffix>#L</urlSuffix>
</link>
</sourceLinks>
<!-- No default documentation link to kotlin-stdlib -->
<noStdlibLink>false</noStdlibLink>
<!-- 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.
Using the Ant task
The Ant task definition is also contained in the dokka-fatjar.jar referenced above. Here's an example of using it:
<project name="Dokka" default="document">
<typedef resource="dokka-antlib.xml" classpath="dokka-fatjar.jar"/>
<target name="document">
<dokka src="src" outputdir="doc" modulename="myproject"/>
</target>
</project>
The Ant task supports the following attributes:
outputDir- the output directory where the documentation is generatedoutputFormat- the output format (see the list of supported formats above)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@sampletag)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 JDKimpliedPlatforms- See platforms section<sourceRoot path="src" platforms="JVM" />- analogue of src, but allows to specify platforms<packageOptions prefix="kotlin" includeNonPublic="false" reportUndocumented="true" skipDeprecated="false"/>- Per package options for packagekotlinand sub-packages of itnoStdlibLink- No default documentation link to kotlin-stdlib<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 locationcacheRoot- Usedefaultor set to custom path to cache directory to enable package-list caching. When set todefault, caches stored in $USER_HOME/.cache/dokka
Using the Command Line
To run Dokka from the command line, download the Dokka jar. To generate documentation, run the following command:
java -jar dokka-fatjar.jar <source directories> <arguments>
Dokka supports the following command line arguments:
-output- the output directory where the documentation is generated-format- the output format:-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@sampletag)-module- 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 packages-nodeprecated- if set, deprecated elements are not included in the generated documentation-impliedPlatforms- List of implied platforms (comma-separated)-packageOptions- List of package options in formatprefix,-deprecated,-privateApi,+warnUndocumented;...-links- External documentation links in formaturl^packageListUrl^^url2...-noStdlibLink- Disable documentation link to stdlib-cacheRoot- Usedefaultor set to custom path to cache directory to enable package-list caching. When set todefault, caches stored in $USER_HOME/.cache/dokka
Output formats
html- minimalistic html format used by defaultjavadoc- Dokka mimic to javadochtml-as-java- ashtmlbut using java syntaxmarkdown- Markdown structured ashtmlgfm- GitHub flavored markdownjekyll- Jekyll compatible markdown
kotlin-website*- internal format used for documentation on kotlinlang.org
Platforms
Dokka can annotate elements with special platform block with platform requirements
Example of usage can be found on kotlinlang.org
Each source root has a list of platforms for which members are suitable. Also, the list of 'implied' platforms is passed to Dokka. If a member is not available for all platforms in the implied platforms set, its documentation will show the list of platforms for which it's available.
Dokka Internals
Documentation Model
Dokka uses Kotlin-as-a-service technology to build code model, then processes it into documentation model.
Documentation model is graph of items describing code elements such as classes, packages, functions, etc.
Each node has semantic attached, e.g. Value:name -> Type:String means that some value name is of type String.
Each reference between nodes also has semantic attached, and there are three of them:
- Member - reference means that target is member of the source, form tree.
- Detail - reference means that target describes source in more details, form tree.
- Link - any link to any other node, free form.
Member & Detail has reverse Owner reference, while Link's back reference is also Link.
Nodes that are Details of other nodes cannot have Members.
Rendering Docs
When we have documentation model, we can render docs in various formats, languages and layouts. We have some core services:
- FormatService -- represents output format
- LocationService -- represents folder and file layout
- SignatureGenerator -- represents target language by generating class/function/package signatures from model
Basically, given the documentation as a model, we do this:
val signatureGenerator = KotlinSignatureGenerator()
val locationService = FoldersLocationService(arguments.outputDir)
val markdown = JekyllFormatService(locationService, signatureGenerator)
val generator = FileGenerator(signatureGenerator, locationService, markdown)
generator.generate(documentation)
Building Dokka
Dokka is built with Gradle. To build it, use ./gradlew build.
Alternatively, open the project directory in IntelliJ IDEA and use the IDE to build and run Dokka.
Here's how to import and configure Dokka in IntelliJ IDEA:
- Select "Open" from the IDEA welcome screen, or File > Open if a project is already open
- Select the directory with your clone of Dokka
- Note: IDEA may have an error after the project is initally opened; it is OK to ignore this as the next step will address this error
- After IDEA opens the project, select File > New > Module from existing sources
and select the
build.gradlefile from the root directory of your Dokka clone - Use the default options and select "OK"
- After Dokka is loaded into IDEA, open the Gradle tool window (View > Tool Windows > Gradle) and click on the top left "Refresh all Gradle projects" button
- Verify the following project settings. In File > Settings > Build, Execution,
Deployment > Build Tools > Gradle > Runner:
- Ensure "Delegate IDE build/run actions to gradle" is checked
- "Gradle Test Runner" should be selected in the "Run tests using" drop-down menu
- Note: After closing and re-opening the project, IDEA may give an error
message: "Error Loading Project: Cannot load 3 modules". Open up the details
of the error, and click "Remove Selected", as these module
.imlfiles are safe to remove.