java - List first N files in SFTP with JSch -

i need recursive list of file names in sftp folder. i'm using following code:

private void getfilesrecursive(list<lsentry> filelist, list<filedto> response, string dirparentname,         sftpmanagerwithpool manager) throws sftpexception {     (lsentry file : filelist) {         if (!file.getattrs().isdir()) {             response.add(new filedto(file.getfilename(), storagetype.folder.getname(),                     new attributes(file.getattrs().getatime(), file.getattrs().getmtime(),                             file.getattrs().getatimestring(), file.getattrs().getmtimestring(),                             file.getattrs().getpermissionsstring(), getpathwitoutrootdirectoryt(dirparentname),                             file.getattrs().getsize(), file.getattrs().isdir())));         } else if (file.getattrs().isdir() && !".".equals(file.getfilename())) {             list<lsentry> files = manager.listfiles(context.getbasepath().concat("/")                     .concat(dirparentname.concat("/").concat(file.getfilename())));             getfilesrecursive(files, response, dirparentname.concat("/").concat(file.getfilename()), manager);         }     } }  public list<filedto> getfiles() throws serviceexception {     session session = null;     sftpmanagerwithpool manager = null;     try {         session = getsession();         manager = new sftpmanagerwithpool(session);         manager.connect();         list<filedto> response = new arraylist<>();         list<lsentry> files = manager                 .listfiles(context.getbasepath().concat("/").concat(context.getpathtoprocess()));         getfilesrecursive(files, response, context.getpathtoprocess(), manager);         return response;     } catch (exception e) {         throw new serviceexception(httpstatus.internal_server_error.value(), e.getmessage(),                 e.getlocalizedmessage());     } {         if (manager != null) {             manager.disconnect();             try {                 returnsession(session);             } catch (exception e) {                 throw new serviceexception(httpstatus.internal_server_error.value(), e.getmessage(),                         e.getlocalizedmessage());             }         }     } } 

the following method in sftpmanagerwithpool :

@suppresswarnings("unchecked") public list<lsentry> listfiles(string pathfrom) throws sftpexception {     if (c == null || session == null || !session.isconnected() || !c.isconnected()) {         throw new sftpexception(errorcode.list_files.ordinal(), "connection server closed. open first.");     }     string filepath = pathfrom + "/";     return c.ls(filepath); } 

everything works no more 5k files when have more files takes lot of time , results in timeouts.

my question is, how can use c.ls(filepath); method list first n files in folder? i'm looking similar linux shell command ls -u | head -4

----edit-----

i modified method listfiles follow still don't better performance:

public list<lsentry> listfiles(string pathfrom, int top) throws sftpexception {         if (c == null || session == null || !session.isconnected() || !c.isconnected()) {             throw new sftpexception(errorcode.list_files.ordinal(), "connection server closed. open first.");         }         string filepath = pathfrom + "/";         list<lsentry> response = new arraylist<>();         c.ls(filepath, new lsentryselector() {              @override             public int select(lsentry record) {                 if (response.size() <= top) {                     response.add(record);                     return lsentryselector.continue;                 } else {                     return lsentryselector.break;                 }             }         });         return response;     } 

thank :)

use overload of channelsftp.ls method takes lsentryselector interface:

public void ls(string path, lsentryselector selector) 

implement lsentryselector.select collect file entries. once have enough of them, make return break.