FunctionRegistryBase¶

FunctionRegistryBase[T] is an abstraction of function registries for registering functions (that produce a result of type T).

Contract (Subset)¶

lookupFunction¶

lookupFunction(
  name: FunctionIdentifier): Option[ExpressionInfo]

Looks up the ExpressionInfo metadata of a user-defined function by the given name

See SimpleFunctionRegistryBase

Used when:

• FunctionRegistryBase is requested to check if a function exists
• SessionCatalog is requested to lookupBuiltinOrTempFunction, lookupBuiltinOrTempTableFunction, lookupPersistentFunction

Registering Named User-Defined Function¶

registerFunction(
  name: FunctionIdentifier,
  info: ExpressionInfo,
  builder: Seq[Expression] => T): Unit

Registers a user-defined function (written in Python, Scala or Java) under the given name

See SimpleFunctionRegistryBase

Used when:

• SessionCatalog is requested to register a catalog function and reset
• SparkSessionExtensions is requested to registerFunctions and registerTableFunctions

Implementations¶

• EmptyFunctionRegistryBase
• FunctionRegistry
• SimpleFunctionRegistryBase
• TableFunctionRegistry

createOrReplaceTempFunction¶

createOrReplaceTempFunction(
  name: String,
  builder: FunctionBuilder,
  source: String): Unit

createOrReplaceTempFunction registers a named function (with a FunctionIdentifier for the given name).

createOrReplaceTempFunction is used when:

• UDFRegistration is requested to register a user-defined function written in Python or Scala