net.sf.farrago.fennel
Class FennelStorage

java.lang.Object
  net.sf.farrago.fennel.FennelStorage

public class FennelStorage
extends Object

FennelStorage is the JNI interface for calling Fennel from Farrago. Most methods have package access only; other classes in this package expose public wrapper methods.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/FennelStorage.java#24 $

Author:

John V. Sichi

Field Summary

(package private) static int	CLOSE_ABORT
(package private) static int	CLOSE_DEALLOCATE
(package private) static int	CLOSE_RESULT

Constructor Summary

FennelStorage()

Method Summary

static void	cancelExecution(long execHandle) Cancels execution of a statement associated with an execution handle.
(package private) static void	deleteExecutionHandle(long execHandle) Deletes the Fennel object corresponding to an execution handle.
(package private) static void	deleteObjectHandle(long handle) Releases a handle obtained via newObjectHandle.
(package private) static long	executeJavaCmd(FemCmd cmd, long execHandle) Executes a command represented as a Java object.
(package private) static String	getAccessorXmiForTupleDescriptor(FemTupleDescriptor tupleDesc) Constructs a FemTupleAccessor for a FemTupleDescriptor.
static int	getHandleCount()
(package private) static long	newExecutionHandle() Allocates a new object in Fennel that Farrago will use to communicate execution state information from Farrago to Fennel.
(package private) static long	newObjectHandle(Object obj) Creates a native handle for a Java object for reference by XML commands.
(package private) static void	setObjectHandle(long handle, Object obj) Changes the object referenced by a handle.
(package private) static int	tupleStreamFetch(long hStream, byte[] byteArray) Fetches a buffer of rows from a stream.
(package private) static void	tupleStreamGraphClose(long hStreamGraph, int action) Closes a stream graph.
(package private) static void	tupleStreamGraphGetInputStreams(long hStreamGraph, String node, List<String> inputs) Find the input of a given stream node in a stream graph.
(package private) static void	tupleStreamGraphOpen(long hStreamGraph, long hTxn, FennelJavaStreamMap javaStreamMap, FennelJavaErrorTarget javaErrorTarget) Opens a stream graph.
(package private) static void	tupleStreamRestart(long hStream) Restarts a stream.
(package private) static int	tupleStreamTransformFetch(long hStream, int execStreamInputOrdinal, byte[] byteArray) Fetches a buffer of rows from a stream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CLOSE_RESULT

static final int CLOSE_RESULT

See Also:

Constant Field Values

CLOSE_ABORT

static final int CLOSE_ABORT

See Also:

Constant Field Values

CLOSE_DEALLOCATE

static final int CLOSE_DEALLOCATE

See Also:

Constant Field Values

Constructor Detail

FennelStorage

public FennelStorage()

Method Detail

newObjectHandle

static long newObjectHandle(Object obj)

Creates a native handle for a Java object for reference by XML commands. After this, the Java object cannot be garbage collected until its owner explicitly calls closeAllocation.

Parameters:

obj - object for which to create a handle, or null to create a placeholder handle

Returns:

native handle

deleteObjectHandle

static void deleteObjectHandle(long handle)

Releases a handle obtained via newObjectHandle. This should only be called from FennelJavaHandle.

Parameters:

handle - the handle to delete

setObjectHandle

static void setObjectHandle(long handle,
                            Object obj)

Changes the object referenced by a handle.

Parameters:

handle - the handle to change

obj - new object

getHandleCount

public static int getHandleCount()

Returns:

count of handles returned by Fennel which have not yet been deleted

getAccessorXmiForTupleDescriptor

static String getAccessorXmiForTupleDescriptor(FemTupleDescriptor tupleDesc)

Constructs a FemTupleAccessor for a FemTupleDescriptor.

Parameters:

tupleDesc - source FemTupleDescriptor

Returns:

XMI string representation of FemTupleAccessor

executeJavaCmd

static long executeJavaCmd(FemCmd cmd,
                           long execHandle)
                    throws SQLException

Executes a command represented as a Java object.

Parameters:

cmd - Java representation of object

execHandle - optional execution handle associated with the command that's used to pass execution state from Farrago to Fennel; set to 0 if there is no handle

Returns:

output object handle if any

Throws:

SQLException

tupleStreamGraphGetInputStreams

static void tupleStreamGraphGetInputStreams(long hStreamGraph,
                                            String node,
                                            List<String> inputs)

Find the input of a given stream node in a stream graph.

Parameters:

hStreamGraph - handle to stream graph

node - stream name

inputs - The names of the input streams are added to this list, in graph edge order.

tupleStreamGraphOpen

static void tupleStreamGraphOpen(long hStreamGraph,
                                 long hTxn,
                                 FennelJavaStreamMap javaStreamMap,
                                 FennelJavaErrorTarget javaErrorTarget)
                          throws SQLException

Opens a stream graph.

Parameters:

hStreamGraph - handle to stream graph

hTxn - handle to txn in which stream is being opened

javaStreamMap - optional FennelJavaStreamMap

javaErrorTarget - error target handles row errors

Throws:

SQLException

tupleStreamFetch

static int tupleStreamFetch(long hStream,
                            byte[] byteArray)
                     throws SQLException

Fetches a buffer of rows from a stream. If unpositioned, this fetches the first rows.

Parameters:

hStream - handle to stream

byteArray - output buffer receives complete tuples

Returns:

number of bytes fetched (at least one tuple should always be fetched, so 0 indicates end of stream)

Throws:

SQLException

tupleStreamTransformFetch

static int tupleStreamTransformFetch(long hStream,
                                     int execStreamInputOrdinal,
                                     byte[] byteArray)
                              throws SQLException

Fetches a buffer of rows from a stream. Specifically, the stream must be a JavaTransformExecStream. If unpositioned, this fetches the first rows. Does not block if no data is available.

Parameters:

hStream - handle to stream

execStreamInputOrdinal - ordinal of the input to fetch from

byteArray - output buffer receives complete tuples

Returns:

number of bytes fetched (0 indicates end of stream, less than 0 indicates no data currently availble)

Throws:

SQLException

tupleStreamRestart

static void tupleStreamRestart(long hStream)
                        throws SQLException

Restarts a stream.

Parameters:

hStream - handle to stream to restart

Throws:

SQLException

tupleStreamGraphClose

static void tupleStreamGraphClose(long hStreamGraph,
                                  int action)
                           throws SQLException

Closes a stream graph.

Parameters:

hStreamGraph - handle to stream graph

action - CLOSE_XXX

Throws:

SQLException

newExecutionHandle

static long newExecutionHandle()

Allocates a new object in Fennel that Farrago will use to communicate execution state information from Farrago to Fennel. Access to that object will be through a handle.

Returns:

the handle that will be used to access the Fennel object

deleteExecutionHandle

static void deleteExecutionHandle(long execHandle)

Deletes the Fennel object corresponding to an execution handle.

Parameters:

execHandle - the execution handle

cancelExecution

public static void cancelExecution(long execHandle)

Cancels execution of a statement associated with an execution handle.

Parameters:

execHandle - the execution handle