private InputStream OpenMultiplePartsWithOffset(FileSystem fs, Path pt, long offset)
throws IOException {
RemoteIterator<LocatedFileStatus> rit = fs.listFiles(pt, false);
Vector<FSDataInputStream> fileHandleList = new Vector<FSDataInputStream>();
while (rit.hasNext()) {
Path path = rit.next().getPath();
String filename =
path.toString().substring(path.getParent().toString().length(), path.toString().length());
if (filename.startsWith("/part-")) {
long filesize = fs.getFileStatus(path).getLen();
if (offset < filesize) {
FSDataInputStream handle = fs.open(path);
if (offset > 0) {
handle.seek(offset);
}
fileHandleList.add(handle);
}
offset -= filesize;
}
}
if (fileHandleList.size() == 1) return fileHandleList.get(0);
else if (fileHandleList.size() > 1) {
Enumeration<FSDataInputStream> enu = fileHandleList.elements();
return new SequenceInputStream(enu);
} else {
System.err.println("Error, no source file loaded. run genSeedDataset.sh fisrt!");
return null;
}
}
/**
* Returns the status of a given cache file on hdfs.
*
* @param conf configuration
* @param cache cache file
* @return FileStatus object of the file
* @throws IOException
*/
public static FileStatus getFileStatus(Configuration conf, URI cache) throws IOException {
FileSystem fileSystem = FileSystem.get(cache, conf);
Path filePath = new Path(cache.getPath());
return fileSystem.getFileStatus(filePath);
}
/**
* Returns mtime of a given cache file on hdfs.
*
* @param conf configuration
* @param cache cache file
* @return mtime of a given cache file on hdfs
* @throws IOException
*/
public static long getTimestamp(Configuration conf, URI cache) throws IOException {
FileSystem fileSystem = FileSystem.get(cache, conf);
Path filePath = new Path(cache.getPath());
return fileSystem.getFileStatus(filePath).getModificationTime();
}