org.asam.ods

Interface ODSReadTransferOperations

All Known Subinterfaces:

ODSReadTransfer

All Known Implementing Classes:

_ODSReadTransferStub, ODSReadTransfer, ODSReadTransfer, ODSReadTransferPOA

public interface ODSReadTransferOperations

The interface which supports a read transfer (from the ODS server to a client) of the content of a file that is under control of the ODS server.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() (31000) Close this ODSReadTransfer interface.
byte[]	getOctetSeq(int maxOctets) (31001) Read a sequence of bytes from the file.
T_LONGLONG	getPosition() (31003) Retrieve the current position of the internal read pointer in the file.
T_LONGLONG	skipOctets(T_LONGLONG numOctets) (31002) Skip a number of bytes while reading the file.

Method Detail

close

void close()
           throws AoException

(31000) Close this ODSReadTransfer interface. This method closes the file on the host computer's file system and destroys this ODSReadTransfer object.

Throws:

AoException - with the following possible error codes: AO_CONNECTION_LOST AO_IMPLEMENTATION_PROBLEM AO_NOT_IMPLEMENTED AO_NO_MEMORY AO_SESSION_NOT_ACTIVE

getOctetSeq

byte[] getOctetSeq(int maxOctets)
                   throws AoException

(31001) Read a sequence of bytes from the file. This method reads the file by the ODS server referenced by this ODSReadTransfer and returns a sequence of bytes from that file. The parameter 'maxOctets' controls the return behavior of the ODS server. If the file contains more bytes than are given by 'maxOctets', only 'maxOctets' bytes will be returned by the first method invocation. A subsequent method invocation will return the next 'maxOctets' bytes from the file, etc., until the complete file contents has been returned. Further method invocations return an empty sequence. If 'maxOctets' is given with a value greater than the file size or equal to the constant READALL(-1), there is no restriction on the number of bytes, and the complete file contents will be returned with only one method invocation. Note that only a sequential reading, starting at the first byte of the file, is supported by this interface. If previous parts of the file need to be accessed again, the current ODSReadTransfer object must be closed and a new one must be instantiated. In case the parameter 'maxOctets' is negative other then the constant READALL the exception AO_BAD_PARAMETER is thrown. In case there is any problem reading the file, the exception AO_SYSTEM_PROBLEM is thrown.

Parameters:

maxOctets - The maximum number of bytes to be returned by one method call.

Returns:

The next (at most 'maxOctets') bytes in the file.

Throws:

AoException - with the following possible error codes: AO_CONNECTION_LOST AO_IMPLEMENTATION_PROBLEM AO_NOT_IMPLEMENTED AO_NO_MEMORY AO_SESSION_NOT_ACTIVE AO_SYSTEM_PROBLEM AO_BAD_PARAMETER

skipOctets

T_LONGLONG skipOctets(T_LONGLONG numOctets)
                      throws AoException

(31002) Skip a number of bytes while reading the file. This method moves the internal read pointer in the file a number of bytes ahead, starting at its current position; it will not return those bytes. The parameter 'numOctets' specifies the number of bytes to skip. The method returns the true number of bytes that were skipped. This may differ from 'numOctets' e.g. if the end of the file was reached. If the internal read pointer has reached the end of the file any further method invocations will return a value of 0 for 'numSkipped'. This method may be invoked several times and may be arbitrarily combined with getOctetSeq(). Note that only a sequential reading, starting at the first byte of the file, is supported by this interface. If previous parts of the file need to be accessed again, the current ODSReadTransfer object must be closed and a new one must be instantiated. If 'numOctets' is given with a value less than 0, the method will throw the exception AO_BAD_PARAMETER and will not perform any file access nor change the internal read pointer.

Parameters:

numOctets - The number of bytes to be skipped.

Returns:

the real number of bytes skipped in the file.

Throws:

AoException - with the following possible error codes: AO_CONNECTION_LOST AO_IMPLEMENTATION_PROBLEM AO_NOT_IMPLEMENTED AO_NO_MEMORY AO_SESSION_NOT_ACTIVE AO_BAD_PARAMETER

getPosition

T_LONGLONG getPosition()
                       throws AoException

(31003) Retrieve the current position of the internal read pointer in the file. This method returns the current byte position of the file pointer. The start of the file corresponds to a position of 0.

Returns:

The current position of the internal read pointer in the file.

Throws:

AoException - with the following possible error codes: AO_CONNECTION_LOST AO_IMPLEMENTATION_PROBLEM AO_NOT_IMPLEMENTED AO_NO_MEMORY AO_SESSION_NOT_ACTIVE