throw new IllegalStateException("No entries to merge have been defined");
merged = true;
// open the compound stream
IndexOutput os = directory.createOutput(fileName);
IOException priorException = null;
try {
// Write the Version info - must be a VInt because CFR reads a VInt
// in older versions!
os.writeVInt(FORMAT_CURRENT);
// Write the number of entries
os.writeVInt(entries.size());
// Write the directory with all offsets at 0.
// Remember the positions of directory entries so that we can
// adjust the offsets later
long totalSize = 0;
for (FileEntry fe : entries) {
fe.directoryOffset = os.getFilePointer();
os.writeLong(0); // for now
os.writeString(IndexFileNames.stripSegmentName(fe.file));
totalSize += fe.dir.fileLength(fe.file);
}
// Pre-allocate size of file as optimization --
// this can potentially help IO performance as
// we write the file and also later during
// searching. It also uncovers a disk-full
// situation earlier and hopefully without
// actually filling disk to 100%:
final long finalLength = totalSize+os.getFilePointer();
os.setLength(finalLength);
// Open the files and copy their data into the stream.
// Remember the locations of each file's data section.
for (FileEntry fe : entries) {
fe.dataOffset = os.getFilePointer();
copyFile(fe, os);
}
// Write the data offsets into the directory of the compound stream
for (FileEntry fe : entries) {
os.seek(fe.directoryOffset);
os.writeLong(fe.dataOffset);
}
assert finalLength == os.length();
// Close the output stream. Set the os to null before trying to
// close so that if an exception occurs during the close, the
// finally clause below will not attempt to close the stream
// the second time.
IndexOutput tmp = os;
os = null;
tmp.close();
} catch (IOException e) {
priorException = e;
} finally {
IOUtils.closeSafely(priorException, os);
}