private PageIO fetchPage( long offset ) throws IOException, EndOfFileExceededException
{
if ( fileChannel.size() < offset + pageSize )
{
// Error : we are past the end of the file
throw new EndOfFileExceededException( "We are fetching a page on " + offset +
" when the file's size is " + fileChannel.size() );
}
else
{
// Read the page