com.vertica.sdk.ScalarFunction Class Reference

Inheritance diagram for com.vertica.sdk.ScalarFunction:

Collaboration diagram for com.vertica.sdk.ScalarFunction:

Classes
enum	InterfaceType

Public Member Functions
final void	cancelUDX (ServerInterface srvInterface)
void	destroy (ServerInterface srvInterface, SizedColumnTypes argTypes)
void	destroy (ServerInterface srvInterface, SizedColumnTypes argTypes, SessionParamWriterMap udSessionParams)
boolean	isCanceled ()
abstract void	processBlock (ServerInterface srvInterface, BlockReader arg_reader, BlockWriter res_writer) throws UdfException, DestroyInvocation
void	setup (ServerInterface srvInterface, SizedColumnTypes argTypes)

Protected Member Functions
void	cancel (ServerInterface srvInterface)
InterfaceType	getInterfaceType ()

Detailed Description

Interface for User-Defined Scalar Function (UDSF). A UDSF produces a single value from a row of data.

A UDSF can be used anywhere a native function can be used, except CREATE TABLE BY PARTITION and SEGMENTED BY expressions.

A ScalarFunction must have an associated ScalarFunctionFactory.

Member Function Documentation

cancel()

void com.vertica.sdk.UDXObject.cancel ( ServerInterface  srvInterface )

protectedinherited

Cancel callback to be overridden by the UDX implementation. Called when the query running the UDX has been canceled.

• This method will be invoked at most once per UDX object. Once a UDX object has been canceled, it will never be un-canceled.
• This method may be called from a separate thread, concurrently with other methods of this UDX object (but never the constructor). Implementations must be thread-safe with all methods of this UDX.
• This method will be invoked for either an explicit user cancel, or in the event of an error during query execution.

Parameters

srvInterface

a ServerInterface object used to communicate with Vertica

Referenced by com.vertica.sdk.UDXObject.cancelUDX().

cancelUDX()

final void com.vertica.sdk.UDXObject.cancelUDX ( ServerInterface  srvInterface )

inherited

Cancel callback invoked when the query running the UDX has been canceled.

See cancel().

Parameters

srvInterface

a ServerInterface object used to communicate with Vertica

destroy() [1/2]

void com.vertica.sdk.UDXFunction.destroy ( ServerInterface  srvInterface, SizedColumnTypes  argTypes  )

inherited

Perform per instance destruction. This function may throw errors

Parameters

srvInterface	a ServerInterface object used to communicate with Vertica
argTypes	the types of the arguments (as SizedColumnTypes)

Referenced by com.vertica.sdk.UDXFunction.destroy().

destroy() [2/2]

void com.vertica.sdk.UDXFunction.destroy ( ServerInterface  srvInterface, SizedColumnTypes  argTypes, SessionParamWriterMap  udSessionParams  )

inherited

Perform per instance destruction and write session parameters to be used by UDxs that are invoked after this one returns. This function may throw errors

Parameters

srvInterface	a ServerInterface object used to communicate with Vertica
argTypes	the types of the arguments (as SizedColumnTypes)
udSessionParams	a SessionParamWriterMap

isCanceled()

boolean com.vertica.sdk.UDXObject.isCanceled ( )

inherited

Returns

true if execution was canceled.

Referenced by com.vertica.sdk.UDXObject.cancelUDX().

processBlock()

abstract void com.vertica.sdk.ScalarFunction.processBlock ( ServerInterface  srvInterface, BlockReader  arg_reader, BlockWriter  res_writer  ) throws UdfException, DestroyInvocation

abstract

Invoke a user defined function on a set of rows. As the name suggests, a batch of rows are passed in for every invocation to amortize performance.

Notes:

• This methods may be invoked by different threads at different times, and by a different thread than the constructor.
• The order in which the function sees rows is not guaranteed.
• To report error to Vertica, throw a UdfException object

Parameters

srvInterface	a ServerInterface object used to communicate with Vertica
arg_reader	input rows
res_writer	output location

Exceptions

UdfException	UDF problem
DestroyInvocation	vertica canceling – do not catch or handle

setup()

void com.vertica.sdk.UDXFunction.setup ( ServerInterface  srvInterface, SizedColumnTypes  argTypes  )

inherited

Perform per instance initialization. This function may throw errors.

Parameters

srvInterface	a ServerInterface object used to communicate with Vertica
argTypes	the types of the arguments (as SizedColumnTypes)