feat: javadoc

Author: matoous

README.md

@@ -271,4 +271,8 @@ export SUMUP_MERCHANT_CODE="your_merchant_code"
 ./gradlew :examples:card-reader-checkout:run
 ```
 
+## Generating Javadoc
+
+Build the aggregated API reference locally with `just javadoc` (or `./gradlew aggregateJavadoc`). The HTML output is placed under `build/docs/javadoc/index.html`.
+
 [docs-badge]: https://img.shields.io/badge/SumUp-documentation-white.svg?logo=data:image/svg+xml;base64,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

build.gradle

@@ -1,5 +1,8 @@
 import com.diffplug.gradle.spotless.SpotlessExtension
 import org.gradle.api.GradleException
+import org.gradle.api.plugins.JavaPlugin
+import org.gradle.api.tasks.SourceSetContainer
+import org.gradle.api.tasks.javadoc.Javadoc
 import org.gradle.jvm.toolchain.JavaToolchainService
 
 plugins {
@@ -77,6 +80,30 @@ tasks.register('codegen') {
     }
 }
 
+def aggregateJavadocTask = tasks.register('aggregateJavadoc', Javadoc) { task ->
+    group = 'documentation'
+    description = 'Generates Javadoc for all Java subprojects.'
+    destinationDir = layout.buildDirectory.dir('docs/javadoc').get().asFile
+    options.addBooleanOption('Xdoclint:none', true)
+    options.quiet()
+}
+
+gradle.projectsEvaluated {
+    aggregateJavadocTask.configure { task ->
+        def javaProjects = subprojects.findAll { project ->
+            project.plugins.hasPlugin(JavaPlugin)
+        }
+
+        def mainSourceSets = javaProjects.collect { project ->
+            project.extensions.getByType(SourceSetContainer).named('main').get()
+        }
+
+        task.dependsOn(javaProjects.collect { project -> project.tasks.named('javadoc') })
+        task.setSource(mainSourceSets.collect { sourceSet -> sourceSet.allJava })
+        task.setClasspath(task.project.files(mainSourceSets.collect { sourceSet -> sourceSet.compileClasspath }))
+    }
+}
+
 nexusPublishing {
     packageGroup.set('com.sumup')
     repositories {

justfile

@@ -16,6 +16,10 @@ go-test:
 build:
 	JAVA_HOME="${JAVA_HOME:-$(/usr/libexec/java_home -v 21)}" ./gradlew build
 
+# Generate aggregated Javadocs for all modules.
+javadoc:
+	JAVA_HOME="${JAVA_HOME:-$(/usr/libexec/java_home -v 21)}" ./gradlew aggregateJavadoc
+
 # Run the basic example (uses the same Java toolchain helper as build).
 example-basic:
 	JAVA_HOME="${JAVA_HOME:-$(/usr/libexec/java_home -v 21)}" ./gradlew :examples:basic:run