EDOBE XDOM PMML Instrukcja Użytkownika Pobierz pdf (Strona 76)

increasing, until releaseRows is called to release some of the read

data rows. Therefore, it is safe to save the value returned by

getRowsReady, and then process that many rows, without calling it

again to check.

Note that different

CNKBufReader objects associated with the same

CNKBuf may have different numbers of rows ready at any given time.

They will all read the same series of data rows, but one

CNKBufReader

may read it in different chunk sizes than another.

CNKBufReader::

virtual int getEOF();

A CNKProc writing a stream of data into a CNKBuf can set an EOF flag

after it has written all of the data to the

CNKBuf that it ever will, to

terminate the series of data rows.

getEOF() returns true (non-zero) if

the current available chunk includes the end of the data. This is still

meaningful when reading the data in a random access mode: that

getEOF() returns true (non-zero) if and only if the current chunk

defined by {

getChunkPosition(), getRowsReady()} contains the end

of the data.

CNKBufReader::

virtual INT64 getTotalNumRows();

If the CNKBuf knows the total number of rows in its data set (it has

reached the

EOF of a sequential stream, or it has a backing file), then

this method returns the total number of rows. If it doesn't know this

information, it returns

-1.

CNKBufReader::

virtual int isReady();

isReady returns true (non-zero) if the CNKBuf is ready to be read.

Normally, this is

true if getRowsReady() is greater than or equal to

getRequestRows(). It also returns true if getEOF() is true, since the

CNKBuf is as ready as it ever will be: it will never have any more rows

available. A

CNKProc calling isReady should check for this case.

isReady() will always return false (zero) if the error string of the

CNKBuf is not NULL: in this case, the CNKProc should not try accessing

the row data.

CNKBufReader::

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