fix: Do not evaluate isClassArityUsageDisabled on every serialize/des… (#157)

* fix: Do not evaluate isClassArityUsageDisabled on every serialize/deserialize function call

* chore: Move isClassArityUsageDisabled to object

Author: s-gelazevicius

modules/scala-api/src/main/scala/org/apache/flinkx/api/serializer/CaseClassSerializer.scala

@@ -22,6 +22,7 @@ import org.apache.flink.api.common.typeutils.TypeSerializer
 import org.apache.flink.api.java.typeutils.runtime.TupleSerializerBase
 import org.apache.flink.core.memory.{DataInputView, DataOutputView}
 import org.apache.flink.types.NullFieldException
+import org.apache.flinkx.api.serializer.CaseClassSerializer.isClassArityUsageDisabled
 import org.slf4j.{Logger, LoggerFactory}
 
 import scala.util.{Failure, Success, Try}
@@ -77,14 +78,6 @@ abstract class CaseClassSerializer[T <: Product](
       createInstance(fields.toArray)
     }
 
-  private def isClassArityUsageDisabled =
-    sys.env
-      .get("DISABLE_CASE_CLASS_ARITY_USAGE")
-      .exists(v =>
-        Try(v.toBoolean)
-          .getOrElse(false)
-      )
-
   def serialize(value: T, target: DataOutputView): Unit = {
     if (arity > 0 && !isClassArityUsageDisabled)
       target.writeInt(value.productArity)
@@ -124,3 +117,13 @@ abstract class CaseClassSerializer[T <: Product](
     createInstance(fields.filter(_ != null))
   }
 }
+
+object CaseClassSerializer {
+  private val isClassArityUsageDisabled =
+    sys.env
+      .get("DISABLE_CASE_CLASS_ARITY_USAGE")
+      .exists(v =>
+        Try(v.toBoolean)
+          .getOrElse(false)
+      )
+}