diff --git a/spark/src/main/scala/org/apache/comet/serde/hash.scala b/spark/src/main/scala/org/apache/comet/serde/hash.scala
index fa40448dd..e695f8b1b 100644
--- a/spark/src/main/scala/org/apache/comet/serde/hash.scala
+++ b/spark/src/main/scala/org/apache/comet/serde/hash.scala
@@ -30,20 +30,10 @@ object CometXxHash64 extends CometExpressionSerde {
       expr: Expression,
       inputs: Seq[Attribute],
       binding: Boolean): Option[ExprOuterClass.Expr] = {
-    val hash = expr.asInstanceOf[XxHash64]
-    for (child <- hash.children) {
-      child.dataType match {
-        case dt: DecimalType if dt.precision > 18 =>
-          // Spark converts decimals with precision > 18 into
-          // Java BigDecimal before hashing
-          withInfo(expr, s"Unsupported datatype: $dt (precision > 18)")
-          return None
-        case dt if !supportedDataType(dt) =>
-          withInfo(expr, s"Unsupported datatype $dt")
-          return None
-        case _ =>
-      }
+    if (!HashUtils.isSupportedType(expr)) {
+      return None
     }
+    val hash = expr.asInstanceOf[XxHash64]
     val exprs = hash.children.map(exprToProtoInternal(_, inputs, binding))
     val seedBuilder = ExprOuterClass.Literal
       .newBuilder()
@@ -60,27 +50,36 @@ object Murmur3Hash extends CometExpressionSerde {
       expr: Expression,
       inputs: Seq[Attribute],
       binding: Boolean): Option[ExprOuterClass.Expr] = {
+    if (!HashUtils.isSupportedType(expr)) {
+      return None
+    }
     val hash = expr.asInstanceOf[Murmur3Hash]
-    for (child <- hash.children) {
+    val exprs = hash.children.map(exprToProtoInternal(_, inputs, binding))
+    val seedBuilder = ExprOuterClass.Literal
+      .newBuilder()
+      .setDatatype(serializeDataType(IntegerType).get)
+      .setIntVal(hash.seed)
+    val seedExpr = Some(ExprOuterClass.Expr.newBuilder().setLiteral(seedBuilder).build())
+    // the seed is put at the end of the arguments
+    scalarExprToProtoWithReturnType("murmur3_hash", IntegerType, exprs :+ seedExpr: _*)
+  }
+}
+
+private object HashUtils {
+  def isSupportedType(expr: Expression): Boolean = {
+    for (child <- expr.children) {
       child.dataType match {
         case dt: DecimalType if dt.precision > 18 =>
           // Spark converts decimals with precision > 18 into
           // Java BigDecimal before hashing
           withInfo(expr, s"Unsupported datatype: $dt (precision > 18)")
-          return None
+          return false
         case dt if !supportedDataType(dt) =>
           withInfo(expr, s"Unsupported datatype $dt")
-          return None
+          return false
         case _ =>
       }
     }
-    val exprs = hash.children.map(exprToProtoInternal(_, inputs, binding))
-    val seedBuilder = ExprOuterClass.Literal
-      .newBuilder()
-      .setDatatype(serializeDataType(IntegerType).get)
-      .setIntVal(hash.seed)
-    val seedExpr = Some(ExprOuterClass.Expr.newBuilder().setLiteral(seedBuilder).build())
-    // the seed is put at the end of the arguments
-    scalarExprToProtoWithReturnType("murmur3_hash", IntegerType, exprs :+ seedExpr: _*)
+    true
   }
 }