Github user viirya commented on a diff in the pull request:
https://github.com/apache/spark/pull/20085#discussion_r158760302
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/objects/objects.scala
---
@@ -182,6 +182,114 @@ case class StaticInvoke(
}
}
+/**
+ * Invokes a call to reference to a static field.
+ *
+ * @param staticObject The target of the static call. This can either be
the object itself
+ * (methods defined on scala objects), or the class
object
+ * (static methods defined in java).
+ * @param dataType The expected return type of the function call.
+ * @param fieldName The field to reference.
+ */
+case class StaticField(
+ staticObject: Class[_],
+ dataType: DataType,
+ fieldName: String) extends Expression with NonSQLExpression {
+
+ val objectName = staticObject.getName.stripSuffix("$")
+
+ override def nullable: Boolean = false
+ override def children: Seq[Expression] = Nil
+
+ override def eval(input: InternalRow): Any =
+ throw new UnsupportedOperationException("Only code-generated
evaluation is supported.")
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ val javaType = ctx.javaType(dataType)
+
+ val code = s"""
+ final $javaType ${ev.value} = $objectName.$fieldName;
+ """
+
+ ev.copy(code = code, isNull = "false")
+ }
+}
+
+/**
+ * Wraps an expression in a try-catch block, which can be used if the body
expression may throw a
+ * exception.
+ *
+ * @param body The expression body to wrap in a try-catch block.
+ * @param dataType The return type of the try block.
+ * @param returnNullable When false, indicating the invoked method will
always return
+ * non-null value.
+ */
+case class WrapException(
+ body: Expression,
+ dataType: DataType,
+ returnNullable: Boolean = true) extends Expression with
NonSQLExpression {
+
+ override def nullable: Boolean = returnNullable
+ override def children: Seq[Expression] = Seq(body)
+
+ override def eval(input: InternalRow): Any =
+ throw new UnsupportedOperationException("Only code-generated
evaluation is supported.")
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ val javaType = ctx.javaType(dataType)
+ val returnName = ctx.freshName("returnName")
+
+ val bodyExpr = body.genCode(ctx)
+
+ val code =
+ s"""
+ |final $javaType $returnName;
+ |try {
+ | ${bodyExpr.code}
+ | $returnName = ${bodyExpr.value};
+ |} catch (Exception e) {
+ | org.apache.spark.unsafe.Platform.throwException(e);
+ |}
+ """.stripMargin
+
+ ev.copy(code = code, isNull = bodyExpr.isNull, value = returnName)
+ }
+}
+
+/**
+ * Returns the value if it is of the specified type, or null otherwise
+ *
+ * @param value The value to returned
+ * @param checkedType The type to check against the value via instanceOf
+ * @param dataType The type returned by the expression
+ */
+case class ValueIfType(
+ value: Expression,
--- End diff --
Should we limit the data type of `value` to `ObjectType`?
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