Initial impl of MysqlQuirks: #8

src/main/kotlin/com/github/vokorm/DB.kt

@@ -11,11 +11,15 @@ import org.sql2o.Connection
 import org.sql2o.converters.Converter
 import org.sql2o.converters.ConverterException
 import org.sql2o.converters.ConvertersProvider
+import org.sql2o.quirks.NoQuirks
+import org.sql2o.quirks.Quirks
+import org.sql2o.quirks.QuirksProvider
 import java.io.Closeable
 import java.sql.Timestamp
 import java.time.Instant
 import java.time.LocalDate
 import java.time.ZoneId
+import java.util.*
 import javax.sql.DataSource
 import javax.validation.NoProviderFoundException
 import javax.validation.Validation
@@ -142,3 +146,45 @@ class VokConvertersProvider : ConvertersProvider {
         }
     }
 }
+
+/**
+ * Converts  [UUID] to [ByteArray] to be able to store UUID into binary(16).
+ * See https://github.com/mvysny/vok-orm/issues/8 for more details.
+ */
+private class MysqlUuidConverter : Converter<UUID> {
+    override fun toDatabaseParam(`val`: UUID?): Any? = when(`val`) {
+        null -> null
+        else -> `val`.toByteArray()
+    }
+
+    override fun convert(`val`: Any?): UUID? = when(`val`) {
+        null -> null
+        is ByteArray -> uuidFromByteArray(`val`)
+        is UUID -> `val`
+        else -> throw IllegalArgumentException("Failed to convert $`val` to UUID")
+    }
+}
+
+/**
+ * Works around MySQL drivers not able to convert [UUID] to [ByteArray].
+ * See https://github.com/mvysny/vok-orm/issues/8 for more details.
+ */
+class MysqlQuirks : NoQuirks(mapOf(UUID::class.java to MysqlUuidConverter()))
+
+/**
+ * Provides specialized quirks for MySQL. See [MysqlQuirks] for more details.
+ */
+class VokOrmQuirksProvider : QuirksProvider {
+    override fun forURL(jdbcUrl: String): Quirks? = when {
+        jdbcUrl.startsWith("jdbc:mysql:") || jdbcUrl.startsWith("jdbc:mariadb:") -> MysqlQuirks()
+        else -> null
+    }
+
+    override fun forObject(jdbcObject: Any): Quirks? {
+        val className = jdbcObject.javaClass.canonicalName
+        return when {
+            className.startsWith("com.mysql.") || className.startsWith("org.mariadb.jdbc.") -> MysqlQuirks()
+            else -> null
+        }
+    }
+}

src/main/kotlin/com/github/vokorm/Utils.kt

@@ -1,7 +1,8 @@
 package com.github.vokorm
 
 import org.slf4j.LoggerFactory
-import java.io.Closeable
+import java.io.*
+import java.util.*
 import javax.validation.ConstraintViolation
 import javax.validation.ValidationException
 import javax.validation.Validator
@@ -39,4 +40,24 @@ object NoopValidator : Validator {
     override fun <T : Any?> unwrap(type: Class<T>?): T = throw ValidationException("unsupported $type")
 
     override fun forExecutables(): ExecutableValidator = throw UnsupportedOperationException("unimplemented")
-}
+}
+
+/**
+ * Converts UUID to a byte array with the length of 16. Writes [UUID.getMostSignificantBits] first, then
+ * [UUID.getLeastSignificantBits].
+ */
+fun UUID.toByteArray(): ByteArray = ByteArrayOutputStream().apply {
+    val dout = DataOutputStream(this)
+    dout.writeLong(mostSignificantBits)
+    dout.writeLong(leastSignificantBits)
+}.toByteArray()
+
+/**
+ * Reads UUID from [bytes].
+ * @param bytes 16-byte-long byte array; first is the [UUID.getMostSignificantBits], then [UUID.getLeastSignificantBits].
+ */
+fun uuidFromByteArray(bytes: ByteArray): UUID {
+    check(bytes.size == 16) { "Expected 16-bytes array but got ${bytes.size}" }
+    val din = DataInputStream(ByteArrayInputStream(bytes))
+    return UUID(din.readLong(), din.readLong())
+}

src/main/resources/META-INF/services/org.sql2o.quirks.QuirksProvider

@@ -0,0 +1 @@
+com.github.vokorm.VokOrmQuirksProvider

src/test/kotlin/com/github/vokorm/UtilsTest.kt

@@ -0,0 +1,12 @@
+package com.github.vokorm
+
+import com.github.mvysny.dynatest.DynaTest
+import java.util.*
+import kotlin.test.expect
+
+class UtilsTest : DynaTest({
+    test("UUID-to-ByteArray") {
+        val uuid = UUID.randomUUID()
+        expect(uuid) { uuidFromByteArray(uuid.toByteArray()) }
+    }
+})