[#7324] Support Kotlin data classes in DefaultRecordMapper

jOOQ/pom.xml

@@ -101,6 +101,11 @@
             <scope>provided</scope>
             <optional>true</optional>
         </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-reflect</artifactId>
+            <version>1.2.30</version>
+        </dependency>
 
         <!-- From JDK 9 onwards, the JAXB dependency needs to be made explicit -->
         <dependency>

jOOQ/src/main/java/org/jooq/impl/DefaultRecordMapper.java

@@ -50,6 +50,7 @@ import static org.jooq.impl.Tools.getMatchingMembers;
 import static org.jooq.impl.Tools.getMatchingSetters;
 import static org.jooq.impl.Tools.getPropertyName;
 import static org.jooq.impl.Tools.hasColumnAnnotations;
+import static org.jooq.impl.Tools.fieldNameStrings;
 import static org.jooq.tools.reflect.Reflect.accessible;
 
 import java.beans.ConstructorProperties;
@@ -79,6 +80,11 @@ import java.util.stream.Stream;
 
 import javax.persistence.Column;
 
+import kotlin.jvm.JvmClassMappingKt;
+import kotlin.reflect.KClass;
+import kotlin.reflect.KFunction;
+import kotlin.reflect.KParameter;
+import kotlin.reflect.full.KClasses;
 import org.jooq.Attachable;
 import org.jooq.Configuration;
 import org.jooq.Field;
@@ -343,6 +349,33 @@ public class DefaultRecordMapper<R extends Record, E> implements RecordMapper<R,
             return;
         }
 
+        // [#7324] Map Kotlin data classes
+        KClass<? extends E> kotlinClass = JvmClassMappingKt.getKotlinClass(type);
+        if (kotlinClass.isData()) {
+            KFunction<? extends E> primaryConstructor = KClasses.getPrimaryConstructor(kotlinClass);
+            List<KParameter> parameters = primaryConstructor.getParameters();
+
+            if (parameters.size() != fields.length) {
+                throw new MappingException("Primary constructor of Kotlin data class " + type + " did not match row type " + rowType);
+            }
+
+            for (String fieldName : fieldNameStrings(fields)) {
+                String name = StringUtils.toCamelCaseLC(fieldName);
+                boolean found = false;
+                for (KParameter kParameter : parameters) {
+                    String parameterName = kParameter.getName();
+                    if (name.equals(parameterName)) {
+                        found = true;
+                    }
+                }
+                if (!found) {
+                    throw new MappingException("Primary constructor of Kotlin data class " + type + " did not match row type " + rowType);
+                }
+            }
+            delegate = new KotlinDataClassMapper(primaryConstructor);
+            return;
+        }
+
         // [#1340] Allow for using non-public default constructors
         try {
             delegate = new MutablePOJOMapper(new ConstructorCall<E>(accessible(type.getDeclaredConstructor())), instance);
@@ -981,6 +1014,44 @@ public class DefaultRecordMapper<R extends Record, E> implements RecordMapper<R,
         }
     }
 
+    private class KotlinDataClassMapper implements RecordMapper<R, E> {
+
+        private final KFunction<? extends E> constructor;
+        private final List<String> parameterNames;
+        private final Class[] parameterTypes;
+        private final Object[] parameterValues;
+
+        KotlinDataClassMapper(KFunction<? extends E> constructor) {
+            this.constructor = constructor;
+            int n = constructor.getParameters().size();
+            this.parameterNames = new ArrayList<>(n);
+            this.parameterValues = new Object[n];
+            this.parameterTypes = new Class[n];
+
+            List<KParameter> parameters = constructor.getParameters();
+            for (int i = 0; i < parameters.size(); i++) {
+                KParameter kParam = parameters.get(i);
+                parameterNames.add(kParam.getName());
+                parameterTypes[i] = JvmClassMappingKt.getJavaClass(((KClass<?>) kParam.getType().getClassifier()));
+            }
+        }
+
+        @Override
+        public E map(R record) {
+            for (int i = 0; i < fields.length; i++) {
+                String name = StringUtils.toCamelCaseLC(fields[i].getName());
+                int index = parameterNames.indexOf(name);
+                if (index < 0) {
+                    throw new MappingException("An error ocurred when mapping record to " + type);
+                }
+                parameterValues[index] = record.get(i);
+            }
+
+            Object[] converted = Convert.convert(parameterValues, parameterTypes);
+            return constructor.call(converted);
+        }
+    }
+
     private static <E> E attach(E attachable, Record record) {
         // [#2869] Attach the mapped outcome if it is Attachable and if the context's
         // Settings.attachRecords flag is set

jOOQ/src/main/resources/META-INF/ABOUT.txt

@@ -55,6 +55,7 @@ Authors and contributors of jOOQ or parts of jOOQ in alphabetical order:
 - Victor Z. Peng
 - Vladimir Kulev
 - Vladimir Vinogradov
+- Vojtech Polivka
 - Wang Gaoyuan
 - Zoltan Tamasi