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CallMethodViaReflection Expression

CallMethodViaReflection is an Expression.md[expression] that represents a static method call in Scala or Java using reflect and java_method functions.

NOTE: reflect and java_method functions are only supported in SparkSession.md#sql[SQL] and spark-sql-dataset-operators.md#selectExpr[expression] modes.

.CallMethodViaReflection's DataType to JVM Types Mapping [cols="1,2",options="header",width="100%"] |=== | DataType | JVM Type

| BooleanType | java.lang.Boolean / scala.Boolean

| ByteType | java.lang.Byte / Byte

| ShortType | java.lang.Short / Short

| IntegerType | java.lang.Integer / Int

| LongType | java.lang.Long / Long

| FloatType | java.lang.Float / Float

| DoubleType | java.lang.Double / Double

| StringType | String |===

[source, scala]

import org.apache.spark.sql.catalyst.expressions.CallMethodViaReflection import org.apache.spark.sql.catalyst.expressions.Literal scala> val expr = CallMethodViaReflection( | Literal("java.time.LocalDateTime") :: | Literal("now") :: Nil) expr: org.apache.spark.sql.catalyst.expressions.CallMethodViaReflection = reflect(java.time.LocalDateTime, now) scala> println(expr.numberedTreeString) 00 reflect(java.time.LocalDateTime, now) 01 :- java.time.LocalDateTime 02 +- now

// CallMethodViaReflection as the expression for reflect SQL function val q = """ select reflect("java.time.LocalDateTime", "now") as now """ val plan = spark.sql(q).queryExecution.logical // CallMethodViaReflection shows itself under "reflect" name scala> println(plan.numberedTreeString) 00 Project [reflect(java.time.LocalDateTime, now) AS now#39] 01 +- OneRowRelation$


CallMethodViaReflection supports a Expression.md#CodegenFallback[fallback mode for expression code generation].

[[properties]] .CallMethodViaReflection's Properties [width="100%",cols="1,2",options="header"] |=== | Property | Description

| [[dataType]] dataType | StringType

| [[deterministic]] deterministic | Disabled (i.e. false)

| [[nullable]] nullable | Enabled (i.e. true)

| [[prettyName]] prettyName | reflect |===

NOTE: CallMethodViaReflection is very similar to spark-sql-Expression-StaticInvoke.md[StaticInvoke] expression.


Last update: 2020-10-21
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