fix: Make using Java's ServiceLoader optional on Database.connect()

documentation-website/Writerside/topics/Getting-Started-with-Exposed.topic

@@ -250,6 +250,12 @@
                     but it does not immediately establish a connection with the database. The actual connection
                     to the database will be established later when a database operation is performed.
                 </note>
+                <note>
+                    By default, Exposed uses a <code>ServiceLoader</code> to get an implementation of the <code>DatabaseConnectionAutoRegistration</code>
+                    interface that represents a connection accessed by the <code>Database</code> instance.
+                    This can be modified when calling the <code>Database.connect</code> method by providing an argument to <code>connectionAutoRegistration</code>
+                    in the parameter list.
+                </note>
                 <p>
                     With this, you've added Exposed to your Kotlin project and configured a database connection.
                     You're now ready to define your data model and engage with the database using Exposed's DSL API.

documentation-website/Writerside/topics/Working-with-Database.md

@@ -24,13 +24,20 @@ val db = Database.connect("jdbc:h2:mem:test", driver = "org.h2.Driver")
 <note>Executing this code more than once per database will create leaks in your application, hence it is recommended to store it for later use:
 <code-block lang="kotlin">
 object DbSettings {
-   val db by lazy { 
-       Database.connect(/* setup connection */)
-   }
+    val db by lazy {
+        Database.connect(/* setup connection */)
+    }
 }
 </code-block>
 </note>
 
+<note>
+    By default, Exposed uses a <code>ServiceLoader</code> to get an implementation of the <code>DatabaseConnectionAutoRegistration</code>
+    interface that represents a connection accessed by the <code>Database</code> instance.
+    This can be modified when calling the <code>Database.connect</code> method by providing an argument to <code>connectionAutoRegistration</code>
+    in the parameter list.
+</note>
+
 ### H2
 
 In order to use H2, you need to add the H2 driver dependency:

exposed-core/api/exposed-core.api

@@ -674,14 +674,14 @@ public final class org/jetbrains/exposed/sql/Database {
 }
 
 public final class org/jetbrains/exposed/sql/Database$Companion {
-	public final fun connect (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
-	public final fun connect (Ljavax/sql/DataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
-	public final fun connect (Lkotlin/jvm/functions/Function0;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
-	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
-	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljavax/sql/DataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
-	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Lkotlin/jvm/functions/Function0;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
-	public final fun connectPool (Ljavax/sql/ConnectionPoolDataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
-	public static synthetic fun connectPool$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljavax/sql/ConnectionPoolDataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
+	public final fun connect (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
+	public final fun connect (Ljavax/sql/DataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
+	public final fun connect (Lkotlin/jvm/functions/Function0;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
+	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
+	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljavax/sql/DataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
+	public static synthetic fun connect$default (Lorg/jetbrains/exposed/sql/Database$Companion;Lkotlin/jvm/functions/Function0;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
+	public final fun connectPool (Ljavax/sql/ConnectionPoolDataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;)Lorg/jetbrains/exposed/sql/Database;
+	public static synthetic fun connectPool$default (Lorg/jetbrains/exposed/sql/Database$Companion;Ljavax/sql/ConnectionPoolDataSource;Lkotlin/jvm/functions/Function1;Lorg/jetbrains/exposed/sql/DatabaseConfig;Lorg/jetbrains/exposed/sql/DatabaseConnectionAutoRegistration;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lorg/jetbrains/exposed/sql/Database;
 	public final fun getDefaultIsolationLevel (Lorg/jetbrains/exposed/sql/Database;)I
 	public final fun getDialectName (Ljava/lang/String;)Ljava/lang/String;
 	public final fun registerDialect (Ljava/lang/String;Lkotlin/jvm/functions/Function0;)V

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Database.kt

@@ -112,9 +112,11 @@ class Database private constructor(
     companion object {
         internal val dialects = ConcurrentHashMap<String, () -> DatabaseDialect>()
 
-        private val connectionInstanceImpl: DatabaseConnectionAutoRegistration =
-            ServiceLoader.load(DatabaseConnectionAutoRegistration::class.java, Database::class.java.classLoader).firstOrNull()
+        private val connectionInstanceImpl: DatabaseConnectionAutoRegistration by lazy {
+            ServiceLoader.load(DatabaseConnectionAutoRegistration::class.java, Database::class.java.classLoader)
+                .firstOrNull()
                 ?: error("Can't load implementation for ${DatabaseConnectionAutoRegistration::class.simpleName}")
+        }
 
         private val driverMapping = mutableMapOf(
             "jdbc:h2" to "org.h2.Driver",
@@ -162,12 +164,13 @@ class Database private constructor(
         private fun doConnect(
             explicitVendor: String?,
             config: DatabaseConfig?,
+            connectionAutoRegistration: DatabaseConnectionAutoRegistration,
             getNewConnection: () -> Connection,
             setupConnection: (Connection) -> Unit = {},
             manager: (Database) -> TransactionManager = { ThreadLocalTransactionManager(it) }
         ): Database {
             return Database(explicitVendor, config ?: DatabaseConfig.invoke()) {
-                connectionInstanceImpl(getNewConnection().apply { setupConnection(this) })
+                connectionAutoRegistration(getNewConnection().apply { setupConnection(this) })
             }.apply {
                 TransactionManager.registerManager(this, manager(this))
             }
@@ -180,6 +183,8 @@ class Database private constructor(
          * but instead provides the details necessary to do so whenever a connection is required by a transaction.
          *
          * @param datasource The [DataSource] object to be used as a means of getting a connection.
+         * @param connectionAutoRegistration The connection provider for database. If not provided,
+         * a service loader will be used to locate and load a provider for [DatabaseConnectionAutoRegistration].
          * @param setupConnection Any setup that should be applied to each new connection.
          * @param databaseConfig Configuration parameters for this [Database] instance.
          * @param manager The [TransactionManager] responsible for new transactions that use this [Database] instance.
@@ -188,14 +193,16 @@ class Database private constructor(
             datasource: DataSource,
             setupConnection: (Connection) -> Unit = {},
             databaseConfig: DatabaseConfig? = null,
+            connectionAutoRegistration: DatabaseConnectionAutoRegistration = connectionInstanceImpl,
             manager: (Database) -> TransactionManager = { ThreadLocalTransactionManager(it) }
         ): Database {
             return doConnect(
                 explicitVendor = null,
                 config = databaseConfig,
                 getNewConnection = { datasource.connection!! },
                 setupConnection = setupConnection,
-                manager = manager
+                manager = manager,
+                connectionAutoRegistration = connectionAutoRegistration
             ).apply {
                 connectsViaDataSource = true
             }
@@ -225,14 +232,16 @@ class Database private constructor(
             datasource: ConnectionPoolDataSource,
             setupConnection: (Connection) -> Unit = {},
             databaseConfig: DatabaseConfig? = null,
+            connectionAutoRegistration: DatabaseConnectionAutoRegistration = connectionInstanceImpl,
             manager: (Database) -> TransactionManager = { ThreadLocalTransactionManager(it) }
         ): Database {
             return doConnect(
                 explicitVendor = null,
                 config = databaseConfig,
                 getNewConnection = { datasource.pooledConnection.connection!! },
                 setupConnection = setupConnection,
-                manager = manager
+                manager = manager,
+                connectionAutoRegistration = connectionAutoRegistration
             )
         }
 
@@ -243,19 +252,23 @@ class Database private constructor(
          * but instead provides the details necessary to do so whenever a connection is required by a transaction.
          *
          * @param getNewConnection A function that returns a new connection.
+         * @param connectionAutoRegistration The connection provider for database. If not provided,
+         * a service loader will be used to locate and load a provider for [DatabaseConnectionAutoRegistration].
          * @param databaseConfig Configuration parameters for this [Database] instance.
          * @param manager The [TransactionManager] responsible for new transactions that use this [Database] instance.
          */
         fun connect(
             getNewConnection: () -> Connection,
             databaseConfig: DatabaseConfig? = null,
+            connectionAutoRegistration: DatabaseConnectionAutoRegistration = connectionInstanceImpl,
             manager: (Database) -> TransactionManager = { ThreadLocalTransactionManager(it) }
         ): Database {
             return doConnect(
                 explicitVendor = null,
                 config = databaseConfig,
                 getNewConnection = getNewConnection,
-                manager = manager
+                manager = manager,
+                connectionAutoRegistration = connectionAutoRegistration
             )
         }
 
@@ -266,6 +279,8 @@ class Database private constructor(
          * but instead provides the details necessary to do so whenever a connection is required by a transaction.
          *
          * @param url The URL that represents the database when getting a connection.
+         * @param connectionAutoRegistration The connection provider for database. If not provided,
+         * a service loader will be used to locate and load a provider for [DatabaseConnectionAutoRegistration].
          * @param driver The JDBC driver class. If not provided, the specified [url] will be used to find
          * a match from the existing driver mappings.
          * @param user The database user that owns the new connections.
@@ -274,25 +289,26 @@ class Database private constructor(
          * @param databaseConfig Configuration parameters for this [Database] instance.
          * @param manager The [TransactionManager] responsible for new transactions that use this [Database] instance.
          */
+        @Suppress("UnusedParameter", "LongParameterList")
         fun connect(
             url: String,
             driver: String = getDriver(url),
             user: String = "",
             password: String = "",
             setupConnection: (Connection) -> Unit = {},
             databaseConfig: DatabaseConfig? = null,
+            connectionAutoRegistration: DatabaseConnectionAutoRegistration = connectionInstanceImpl,
             manager: (Database) -> TransactionManager = { ThreadLocalTransactionManager(it) }
         ): Database {
             Class.forName(driver).getDeclaredConstructor().newInstance()
             val dialectName = getDialectName(url) ?: error("Can't resolve dialect for connection: $url")
             return doConnect(
-                dialectName,
-                databaseConfig,
-                {
-                    DriverManager.getConnection(url, user, password)
-                },
-                setupConnection,
-                manager
+                explicitVendor = dialectName,
+                config = databaseConfig,
+                getNewConnection = { DriverManager.getConnection(url, user, password) },
+                setupConnection = setupConnection,
+                manager = manager,
+                connectionAutoRegistration = connectionAutoRegistration,
             )
         }