Initial Kotlin support (#210)

* Initial Kotlin support

* Simplify sentence

pom.xml

@@ -17,6 +17,7 @@
         <module>spring-auto-restdocs-core</module>
         <module>spring-auto-restdocs-example</module>
         <module>spring-auto-restdocs-docs</module>
+        <module>spring-auto-restdocs-dokka-json</module>
     </modules>
 
     <organization>
@@ -126,6 +127,8 @@
                     <roots>
                         <root>src/main/java</root>
                         <root>src/test/java</root>
+                        <root>src/main/kotlin</root>
+                        <root>src/test/kotlin</root>
                     </roots>
                 </configuration>
                 <executions>

spring-auto-restdocs-core/src/main/java/capital/scalable/restdocs/jackson/FieldDocumentationObjectVisitor.java

@@ -7,9 +7,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- *
+ * 
  *      http://www.apache.org/licenses/LICENSE-2.0
- *
+ * 
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -51,6 +51,11 @@ public FieldDocumentationObjectVisitor(SerializerProvider provider,
         this.typeFactory = typeFactory;
     }
 
+    @Override
+    public void property(BeanProperty prop) throws JsonMappingException {
+        optionalProperty(prop);
+    }
+
     @Override
     public void optionalProperty(BeanProperty prop) throws JsonMappingException {
         String jsonName = prop.getName();

spring-auto-restdocs-dokka-json/.gitignore

@@ -0,0 +1,29 @@
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# IntelliJ
+.idea/
+*.iml
+
+# Genertaed files
+target/

spring-auto-restdocs-dokka-json/README.md

@@ -0,0 +1,42 @@
+# KDoc and Javadoc to JSON converter for Spring Auto REST Docs
+
+This library is a [Dokka](https://github.com/Kotlin/dokka) extension.
+Dokka is a documentation engine for Kotlin, performing the same function as Javadoc for Java.
+Mixed-language Java/Kotlin projects are fully supported.
+Dokka understands standard Javadoc comments in Java files and KDoc comments in Kotlin files.
+The same holds true for this Dokka extension.
+
+## Usage with Maven
+
+This Dokka extension can be used with the standard `dokka-maven-plugin`.
+To avoid any incompatibilities, the Dokka version of the `dokka-maven-plugin` and of this extension should be the same.
+If this extension is included as a dependency of the plugin, the output format `auto-restdocs-json` can be used.
+
+Example usage:
+```
+            <plugin>
+                <groupId>org.jetbrains.dokka</groupId>
+                <artifactId>dokka-maven-plugin</artifactId>
+                <version>${dokka.version}</version>
+                <executions>
+                    <execution>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>dokka</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <dependencies>
+                    <dependency>
+                        <groupId>capital.scalable</groupId>
+                        <artifactId>spring-auto-restdocs-dokka-json</artifactId>
+                        <version>${spring-auto-restdocs-dokka-json.version}</version>
+                    </dependency>
+                </dependencies>
+                <configuration>
+                    <outputFormat>auto-restdocs-json</outputFormat>
+                    <outputDir>${jsonDirectory}</outputDir>
+                </configuration>
+            </plugin>
+```
+

spring-auto-restdocs-dokka-json/pom.xml

@@ -0,0 +1,96 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>capital.scalable</groupId>
+        <artifactId>spring-auto-restdocs-parent</artifactId>
+        <version>1.0.12-SNAPSHOT</version>
+        <relativePath>..</relativePath>
+    </parent>
+
+    <artifactId>spring-auto-restdocs-dokka-json</artifactId>
+    <packaging>jar</packaging>
+
+    <name>Spring Auto REST Docs Dokka JSON</name>
+    <description>Dokka extension that produces Spring Auto REST Docs' JSON format</description>
+    <url>https://github.com/scacap/spring-auto-restdocs</url>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <kotlin.version>1.2.30</kotlin.version>
+        <junit.version>4.12</junit.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test-junit</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.dokka</groupId>
+            <artifactId>dokka-fatjar</artifactId>
+            <version>0.9.16</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-core</artifactId>
+            <version>2.9.4</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-kotlin</artifactId>
+            <version>2.9.4.1</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <sourceDirectory>src/main/kotlin</sourceDirectory>
+        <testSourceDirectory>src/test/kotlin</testSourceDirectory>
+
+        <plugins>
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${kotlin.version}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>test-compile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>jcenter</id>
+            <url>https://jcenter.bintray.com/</url>
+        </repository>
+    </repositories>
+
+</project>

spring-auto-restdocs-dokka-json/src/main/kotlin/capital/scalable/dokka/json/JsonFileGenerator.kt

@@ -0,0 +1,85 @@
+/*-
+ * #%L
+ * Spring Auto REST Docs Dokka JSON
+ * %%
+ * Copyright (C) 2015 - 2018 Scalable Capital GmbH
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+package capital.scalable.dokka.json
+
+import com.google.inject.Inject
+import org.jetbrains.dokka.*
+import java.io.File
+import java.io.FileOutputStream
+import java.io.IOException
+import java.io.OutputStreamWriter
+
+class JsonFileGenerator @Inject constructor(val locationService: FileLocationService) : Generator {
+
+    @set:Inject(optional = true)
+    lateinit var formatService: FormatService
+
+    override fun buildPages(nodes: Iterable<DocumentationNode>) {
+        val specificLocationService = locationService.withExtension(formatService.extension)
+
+        for ((_, items) in nodes.groupBy { specificLocationService.location(it) }) {
+            if (items.any { it.kind == NodeKind.Class }) {
+                val location = locationOverride(items.find { it.kind == NodeKind.Class }!!)
+                val file = location.file
+                file.parentFile?.mkdirsOrFail()
+                try {
+                    FileOutputStream(file).use {
+                        OutputStreamWriter(it, Charsets.UTF_8).use {
+                            it.write(formatService.format(location, items))
+                        }
+                    }
+                } catch (e: Throwable) {
+                    println(e)
+                }
+            }
+            buildPages(items.flatMap { it.members })
+        }
+    }
+
+    private fun locationOverride(node: DocumentationNode): FileLocation {
+        val path = node.path
+                // Remove class name. It is appended again below.
+                .dropLast(1)
+                .filter { it.name.isNotEmpty() && it.kind != NodeKind.Module }
+                .joinToString("") {
+                    if (it.kind == NodeKind.Class) {
+                        // Parent class if the node is a nested class
+                        "${it.name}."
+                    } else {
+                        // Turn package dots into folders
+                        "${it.name.replace(".", "/")}/"
+                    }
+                }
+        val className = node.name
+        return FileLocation(File(locationService.root.path, "$path$className.json"))
+    }
+
+    override fun buildOutlines(nodes: Iterable<DocumentationNode>) {}
+
+    override fun buildSupportFiles() {}
+
+    override fun buildPackageList(nodes: Iterable<DocumentationNode>) {}
+
+    private fun File.mkdirsOrFail() {
+        if (!mkdirs() && !exists()) {
+            throw IOException("Failed to create directory $this")
+        }
+    }
+}

spring-auto-restdocs-dokka-json/src/main/kotlin/capital/scalable/dokka/json/JsonFormatDescriptor.kt

@@ -0,0 +1,40 @@
+/*-
+ * #%L
+ * Spring Auto REST Docs Dokka JSON
+ * %%
+ * Copyright (C) 2015 - 2018 Scalable Capital GmbH
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+package capital.scalable.dokka.json
+
+import org.jetbrains.dokka.*
+import org.jetbrains.dokka.Formats.FormatDescriptor
+import org.jetbrains.dokka.Kotlin.KotlinDescriptorSignatureProvider
+import org.jetbrains.dokka.Samples.DefaultSampleProcessingService
+import org.jetbrains.dokka.Samples.SampleProcessingService
+import kotlin.reflect.KClass
+
+class JsonFormatDescriptor : FormatDescriptor {
+    override val formatServiceClass = JsonFormatService::class
+
+    override val packageDocumentationBuilderClass = KotlinPackageDocumentationBuilder::class
+    override val javaDocumentationBuilderClass = KotlinJavaDocumentationBuilder::class
+
+    override val generatorServiceClass = JsonFileGenerator::class
+    override val outlineServiceClass: KClass<out OutlineFormatService>? = null
+    override val sampleProcessingService: KClass<out SampleProcessingService> = DefaultSampleProcessingService::class
+    override val packageListServiceClass: KClass<out PackageListService>? = DefaultPackageListService::class
+    override val descriptorSignatureProvider = KotlinDescriptorSignatureProvider::class
+}