spark技术分享CallMethodViaReflection Expression
CallMethodViaReflection is an expression that represents a static method call in Scala or Java using reflect and java_method functions.
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reflect and java_method functions are only supported in SQL and expression modes.
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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 fallback mode for expression code generation.
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Disabled (i.e. |
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Enabled (i.e. |
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Note
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CallMethodViaReflection is very similar to StaticInvoke expression.
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