public LineFileDocs(Random random,String path) throws IOException {
  this.path=path;
  this.random=new Random(random.nextLong());
  open(random);
}

public LineFileDocs ( Random random , String path ) throws IOException { this . path = path ; this . random = new Random ( random . nextLong ( ) ) ; open ( random ) ; }
if forever is true , we rewind the file at eof ( repeat the docs over and over )
