Linter

Author: zaleslaw

dataframe-jdbc/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/db/DuckDb.kt

@@ -256,6 +256,5 @@ public object DuckDb : DbType("duckdb") {
      * Checks if the DuckDB URL represents an in-memory database.
      * In-memory DuckDB URLs are either "jdbc:duckdb:" or "jdbc:duckdb:" followed only by whitespace.
      */
-    private fun String.isInMemoryDuckDb(): Boolean =
-        this == "jdbc:duckdb:" || matches("jdbc:duckdb:\\s*$".toRegex())
+    private fun String.isInMemoryDuckDb(): Boolean = this == "jdbc:duckdb:" || matches("jdbc:duckdb:\\s*$".toRegex())
 }

dataframe-jdbc/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/db/Sqlite.kt

@@ -32,8 +32,8 @@ public object Sqlite : DbType("sqlite") {
 
     override fun convertSqlTypeToKType(tableColumnMetadata: TableColumnMetadata): KType? = null
 
-    override fun createConnection(dbConfig: DbConnectionConfig): Connection {
-        return if (dbConfig.readOnly) {
+    override fun createConnection(dbConfig: DbConnectionConfig): Connection =
+        if (dbConfig.readOnly) {
             try {
                 // Use SQLiteConfig to set read-only mode before a connection establishment
                 val configClass = Class.forName("org.sqlite.SQLiteConfig")
@@ -49,6 +49,4 @@ public object Sqlite : DbType("sqlite") {
         } else {
             DriverManager.getConnection(dbConfig.url, dbConfig.user, dbConfig.password)
         }
-    }
-
 }

dataframe-jdbc/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/sqliteTest.kt

@@ -13,7 +13,6 @@ import java.io.File
 import java.nio.file.Files
 import java.sql.Connection
 import java.sql.DriverManager
-import java.sql.SQLException
 import kotlin.reflect.typeOf
 
 @DataSchema
@@ -50,20 +49,22 @@ interface CustomerOrderSQLite {
 class SqliteTest {
     companion object {
         private lateinit var connection: Connection
-        // we are using a temporary file because we need to test requests with DBConnectionConfig,
-        // which creates a connection under the hood and need to have access to the shared SQLite database
+
+        /**
+         * We are using a temporary file because we need to test requests with DBConnectionConfig,
+         * which creates a connection under the hood and need to have access to the shared SQLite database
+         */
         private lateinit var testDbFile: File
-        private lateinit var DATABASE_URL: String
+        private lateinit var databaseUrl: String
 
         @BeforeClass
         @JvmStatic
         fun setUpClass() {
             testDbFile = Files.createTempFile("dataframe_sqlite_test_", ".db").toFile()
             testDbFile.deleteOnExit() // if fails
 
-            DATABASE_URL = "jdbc:sqlite:${testDbFile.absolutePath}"
-            connection = DriverManager.getConnection(DATABASE_URL)
-
+            databaseUrl = "jdbc:sqlite:${testDbFile.absolutePath}"
+            connection = DriverManager.getConnection(databaseUrl)
 
             @Language("SQL")
             val createCustomersTableQuery = """
@@ -146,7 +147,6 @@ class SqliteTest {
                 println("Warning: Could not clean up test database file: ${e.message}")
             }
         }
-
     }
 
     @Test
@@ -177,7 +177,7 @@ class SqliteTest {
     fun `read from tables with DBConnectionConfig`() {
         val customerTableName = "Customers"
 
-        val dbConnectionConfig = DbConnectionConfig(DATABASE_URL)
+        val dbConnectionConfig = DbConnectionConfig(databaseUrl)
 
         val df = DataFrame.readSqlTable(dbConnectionConfig, customerTableName).cast<CustomerSQLite>()
         val result = df.filter { it[CustomerSQLite::name] == "John Doe" }
@@ -231,7 +231,7 @@ class SqliteTest {
 
     @Test
     fun `read from sql query with DBConnectionConfig`() {
-        val dbConnectionConfig = DbConnectionConfig(DATABASE_URL)
+        val dbConnectionConfig = DbConnectionConfig(databaseUrl)
 
         val df = DataFrame.readSqlQuery(dbConnectionConfig, sqlQuery).cast<CustomerOrderSQLite>()
         val result = df.filter { it[CustomerOrderSQLite::customerSalary] > 1 }