Map decoder should support UTF8 strings

sksamuel · Apr 26, 2024 · 3f58b96 · 3f58b96
1 parent 7119ef5
commit 3f58b96
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Showing 3 changed files with 26 additions and 1 deletion.
diff --git a/centurion-avro/src/main/kotlin/com/sksamuel/centurion/avro/decoders/collections.kt b/centurion-avro/src/main/kotlin/com/sksamuel/centurion/avro/decoders/collections.kt
@@ -31,7 +31,13 @@ class MapDecoder<T>(private val decoder: Decoder<T>) : Decoder<Map<String, T>> {
    override fun decode(schema: Schema, value: Any?): Map<String, T> {
       require(schema.type == Schema.Type.MAP)
       return when (value) {
-         is Map<*, *> -> value.map { (k, v) -> Pair(k as String, decoder.decode(schema.valueType, v)) }.toMap()
+         is Map<*, *> -> value.map { (k, v) ->
+            Pair(
+               StringDecoder.decode(StringDecoder.STRING_SCHEMA, k),
+               decoder.decode(schema.valueType, v)
+            )
+         }.toMap()
+
          else -> error("Unsupported map type $value")
       }
    }

diff --git a/centurion-avro/src/main/kotlin/com/sksamuel/centurion/avro/decoders/strings.kt b/centurion-avro/src/main/kotlin/com/sksamuel/centurion/avro/decoders/strings.kt
@@ -12,6 +12,9 @@ import java.nio.ByteBuffer
  * the schema, but are nevertheless usable.
  */
 object StringDecoder : Decoder<String> {
+
+   val STRING_SCHEMA = Schema.create(Schema.Type.STRING)
+
    override fun decode(schema: Schema, value: Any?): String {
       return when (value) {
          is Utf8 -> value.toString()

diff --git a/...on-avro/src/test/kotlin/com/sksamuel/centurion/avro/decoders/SpecificRecordDecoderTest.kt b/...on-avro/src/test/kotlin/com/sksamuel/centurion/avro/decoders/SpecificRecordDecoderTest.kt
@@ -123,6 +123,22 @@ class SpecificRecordDecoderTest : FunSpec({
       SpecificRecordDecoder(Foo::class, schema).decode(schema, record) shouldBe Foo(map)
    }
 
+   test("maps using UTF8") {
+      data class Foo(val map: Map<String, Int>)
+
+      val schema = SchemaBuilder.record("Foo").namespace(Foo::class.java.packageName)
+         .fields()
+         .name("map").type().map().values().intType().noDefault()
+         .endRecord()
+
+      val map = mapOf(Utf8("a") to 1, "b" to 2)
+
+      val record = GenericData.Record(schema)
+      record.put("map", map)
+
+      SpecificRecordDecoder(Foo::class, schema).decode(schema, record) shouldBe Foo(mapOf("a" to 1, "b" to 2))
+   }
+
    test("maps of maps") {
       data class Foo(val map: Map<String, Map<String, Int>>)