Add row mapping annotation and auto discovery

sadu-mapper/build.gradle.kts

@@ -2,4 +2,13 @@ description = "SADU module to map values received from a database to java object
 
 dependencies {
     api(project(":sadu-core"))
+
+    testImplementation("org.postgresql", "postgresql", "42.7.3")
+    testImplementation(testlibs.bundles.junit)
+    testImplementation(project(":sadu-queries"))
+    testImplementation(project(":sadu-datasource"))
+    testImplementation(project(":sadu-postgresql"))
+
+    testImplementation(testlibs.bundles.database.postgres)
+    testImplementation(testlibs.slf4j.noop)
 }

sadu-mapper/src/main/java/de/chojo/sadu/mapper/RowMapperRegistry.java

@@ -6,26 +6,39 @@
 
 package de.chojo.sadu.mapper;
 
+import de.chojo.sadu.mapper.annotation.MappingProvider;
+import de.chojo.sadu.mapper.exceptions.InvalidMappingException;
 import de.chojo.sadu.mapper.exceptions.MappingAlreadyRegisteredException;
 import de.chojo.sadu.mapper.exceptions.MappingException;
 import de.chojo.sadu.mapper.rowmapper.RowMapper;
+import de.chojo.sadu.mapper.rowmapper.RowMapping;
+import de.chojo.sadu.mapper.wrapper.Row;
+import org.slf4j.Logger;
 
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.sql.ResultSet;
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
+import static org.slf4j.LoggerFactory.getLogger;
+
 /**
  * Class to register {@link RowMapper} to map rows to objects.
  */
 public class RowMapperRegistry {
     private final Map<Class<?>, List<RowMapper<?>>> mapper = new HashMap<>();
+    private static final Logger log = getLogger(RowMapperRegistry.class);
 
     public RowMapperRegistry() {
     }
@@ -176,6 +189,67 @@ public <T> RowMapper<T> findOrWildcard(Class<T> clazz, ResultSetMetaData meta, M
         if (mapper.isPresent()) {
             return mapper.get();
         }
+
+        // Autodetect mapper if available
+        if (register(clazz)) {
+            return findOrWildcard(clazz, meta, config);
+        }
+
         throw MappingException.create(clazz, meta);
     }
+
+    public <V> boolean register(Class<V> clazz) {
+        boolean method = discoverMethodMapping(clazz);
+        boolean constructor = discoverConstructorMapping(clazz);
+        if (method || constructor) return true;
+        throw new InvalidMappingException("No mapping was detected for class %s".formatted(clazz.getName()));
+    }
+
+    @SuppressWarnings("unchecked")
+    private <V> boolean discoverMethodMapping(Class<V> clazz) {
+        List<Method> methods = Arrays.stream(clazz.getDeclaredMethods())
+                .filter(method -> method.isAnnotationPresent(MappingProvider.class) && Modifier.isStatic(method.getModifiers()))
+                .toList();
+
+        for (Method method : methods) {
+            MappingProvider provider = method.getAnnotation(MappingProvider.class);
+            RowMapping<V> mapper;
+            try {
+                mapper = (RowMapping<V>) method.invoke(null);
+            } catch (IllegalAccessException | InvocationTargetException | ClassCastException e) {
+                throw new InvalidMappingException("Could not retrieve mapping. Method has to return %s<%s> and take no arguments".formatted(RowMapping.class.getName(), clazz.getName()), e);
+            }
+            register(RowMapper.forClass(clazz).mapper(mapper).addColumns(provider.value()).build());
+            log.info("Registered method auto mapping for {} with rows {}", clazz.getName(), provider.value());
+
+        }
+        return !methods.isEmpty();
+    }
+
+    @SuppressWarnings("unchecked")
+    private <V> boolean discoverConstructorMapping(Class<V> clazz) {
+        List<Constructor<?>> constructors = Arrays.stream(clazz.getDeclaredConstructors())
+                .filter(constr -> constr.isAnnotationPresent(MappingProvider.class))
+                .toList();
+
+        for (Constructor<?> constructor : constructors) {
+            MappingProvider provider = constructor.getAnnotation(MappingProvider.class);
+            if (constructor.getParameterCount() != 1) {
+                throw new InvalidMappingException("Signature of a constructor with MappingProvider should be Constructor(Row)");
+            }
+            if (constructor.getParameterTypes()[0] != Row.class) {
+                throw new InvalidMappingException("Signature of a constructor with MappingProvider should be Constructor(Row), but was Constructor(%s)".formatted(constructor.getParameterTypes()[0].getName()));
+            }
+
+            register(RowMapper.forClass(clazz).mapper(row -> {
+                try {
+                    return (V) constructor.newInstance(row);
+                } catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
+                    throw new InvalidMappingException("Failed to create instance from RowMapping via constructor");
+                }
+            }).addColumns(provider.value()).build());
+            log.info("Registered constructor auto mapping for {} with rows {}", clazz.getName(), provider.value());
+        }
+        return !constructors.isEmpty();
+    }
 }

sadu-mapper/src/main/java/de/chojo/sadu/mapper/annotation/MappingProvider.java

@@ -0,0 +1,18 @@
+/*
+ *     SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ *     Copyright (C) RainbowDashLabs and Contributor
+ */
+
+package de.chojo.sadu.mapper.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
+public @interface MappingProvider {
+    String[] value();
+}

sadu-mapper/src/main/java/de/chojo/sadu/mapper/exceptions/InvalidMappingException.java

@@ -0,0 +1,18 @@
+/*
+ *     SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ *     Copyright (C) RainbowDashLabs and Contributor
+ */
+
+package de.chojo.sadu.mapper.exceptions;
+
+public class InvalidMappingException extends RuntimeException {
+
+    public InvalidMappingException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public InvalidMappingException(String message) {
+        super(message);
+    }
+}

sadu-mapper/src/test/java/de/chojo/sadu/mapper/PostgresDatabase.java

@@ -0,0 +1,23 @@
+/*
+ *     SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ *     Copyright (C) RainbowDashLabs and Contributor
+ */
+
+package de.chojo.sadu.mapper;
+
+import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.containers.wait.strategy.Wait;
+import org.testcontainers.utility.DockerImageName;
+
+public class PostgresDatabase {
+    public static GenericContainer<?> createContainer(String user, String pw) {
+        GenericContainer<?> self = new GenericContainer<>(DockerImageName.parse("postgres:latest"))
+                .withExposedPorts(5432)
+                .withEnv("POSTGRES_USER", user)
+                .withEnv("POSTGRES_PASSWORD", pw)
+                .waitingFor(Wait.forLogMessage(".*database system is ready to accept connections.*", 2));
+        self.start();
+        return self;
+    }
+}

sadu-mapper/src/test/java/de/chojo/sadu/mapper/annotation/MappingProviderTest.java

@@ -0,0 +1,121 @@
+/*
+ *     SPDX-License-Identifier: LGPL-3.0-or-later
+ *
+ *     Copyright (C) RainbowDashLabs and Contributor
+ */
+
+package de.chojo.sadu.mapper.annotation;
+
+import de.chojo.sadu.datasource.DataSourceCreator;
+import de.chojo.sadu.mapper.RowMapperRegistry;
+import de.chojo.sadu.mapper.exceptions.InvalidMappingException;
+import de.chojo.sadu.mapper.rowmapper.RowMapping;
+import de.chojo.sadu.mapper.wrapper.Row;
+import de.chojo.sadu.postgresql.databases.PostgreSql;
+import de.chojo.sadu.postgresql.mapper.PostgresqlMapper;
+import de.chojo.sadu.queries.api.configuration.QueryConfiguration;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.testcontainers.containers.GenericContainer;
+
+import javax.sql.DataSource;
+import java.io.IOException;
+import java.sql.SQLException;
+
+import static de.chojo.sadu.mapper.PostgresDatabase.createContainer;
+import static de.chojo.sadu.queries.api.query.Query.query;
+
+public class MappingProviderTest {
+
+
+    private static GenericContainer<?> pg;
+
+    @BeforeAll
+    static void beforeAll() throws IOException {
+        pg = createContainer("postgres", "postgres");
+        DataSource dc = DataSourceCreator.create(PostgreSql.get())
+                .configure(c -> c.host(pg.getHost()).port(pg.getFirstMappedPort())).create()
+                .usingPassword("postgres")
+                .usingUsername("postgres")
+                .build();
+        QueryConfiguration.setDefault(QueryConfiguration.builder(dc)
+                .setRowMapperRegistry(new RowMapperRegistry().register(PostgresqlMapper.getDefaultMapper()))
+                .build());
+    }
+
+    @Test
+    public void testMethodMapperRegistration() {
+        MethodMappedClass methodMappedClass = query("Select 'test' as test")
+                .single()
+                .mapAs(MethodMappedClass.class)
+                .first()
+                .get();
+        Assertions.assertEquals(methodMappedClass.test, "test");
+    }
+
+    @Test
+    public void testConstructorMapperRegistration() {
+        ConstructorMappedClass methodMappedClass = query("Select 'test' as test")
+                .single()
+                .mapAs(ConstructorMappedClass.class)
+                .first()
+                .get();
+        Assertions.assertEquals(methodMappedClass.test, "test");
+    }
+
+    @Test
+    public void testInvalidRegistration() {
+        Assertions.assertThrows(InvalidMappingException.class, () -> {
+            query("Select 'test' as test")
+                    .single()
+                    .mapAs(InvalidClass.class)
+                    .first();
+        });
+    }
+
+    @AfterAll
+    static void afterAll() throws IOException {
+        pg.close();
+    }
+
+    public static class MethodMappedClass {
+
+        String test;
+
+        public MethodMappedClass(String test) {
+            this.test = test;
+        }
+
+        @MappingProvider({"test"})
+        public static RowMapping<MethodMappedClass> map() {
+            return row -> new MethodMappedClass(row.getString(1));
+        }
+    }
+
+    public static class ConstructorMappedClass {
+
+        String test;
+
+        public ConstructorMappedClass(String test) {
+            this.test = test;
+        }
+
+        @MappingProvider({"test"})
+        public ConstructorMappedClass(Row row) throws SQLException {
+            this.test = row.getString("test");
+        }
+
+    }
+
+    public static class InvalidClass {
+
+        String test;
+
+        @MappingProvider({"test"})
+        public InvalidClass(String test) {
+            this.test = test;
+        }
+    }
+}

settings.gradle.kts

@@ -49,7 +49,7 @@ dependencyResolutionManagement {
             version("junit", "5.11.0")
             library("junit-jupiter", "org.junit.jupiter", "junit-jupiter").versionRef("junit")
             library("junit-params", "org.junit.jupiter", "junit-jupiter-params").versionRef("junit")
-            bundle("junit", listOf("junit-jupiter", "junit-params"))
+            bundle("junit", listOf("junit-jupiter", "junit-params", "slf4j-simple"))
 
             version("testcontainers", "1.20.1")
             library("testcontainers-postgres", "org.testcontainers", "postgresql").versionRef("testcontainers")
@@ -60,6 +60,7 @@ dependencyResolutionManagement {
 
             version("slf4j", "2.0.16")
             library("slf4j-noop", "org.slf4j", "slf4j-nop").versionRef("slf4j")
+            library("slf4j-simple", "org.slf4j", "slf4j-simple").versionRef("slf4j")
 
             library("driver-postgres", "org.postgresql:postgresql:42.7.3")
             library("driver-mariadb", "org.mariadb.jdbc:mariadb-java-client:3.4.1")