@Override public IndexInput openInput(String name,IOContext context) throws IOException {
  ensureOpen();
  ensureCanRead(name);
  Path path=directory.resolve(name);
  try (FileChannel c=FileChannel.open(path,StandardOpenOption.READ)){
    final String resourceDescription="MMapIndexInput(path=\"" + path.toString() + "\")";
    final boolean useUnmap=getUseUnmap();
    return ByteBufferIndexInput.newInstance(resourceDescription,map(resourceDescription,c,0,c.size()),c.size(),chunkSizePower,new ByteBufferGuard(resourceDescription,useUnmap ? CLEANER : null));
  }
 }

@ Override public IndexInput openInput ( String name , IOContext context ) throws IOException { ensureOpen ( ) ; ensureCanRead ( name ) ; Path path = directory . resolve ( name ) ; try ( FileChannel c = FileChannel . open ( path , StandardOpenOption . READ ) ) { final String resourceDescription = "MMapIndexInput(path=\"" + path . toString ( ) + "\")" ; final boolean useUnmap = getUseUnmap ( ) ; return ByteBufferIndexInput . newInstance ( resourceDescription , map ( resourceDescription , c , 0 , c . size ( ) ) , c . size ( ) , chunkSizePower , new ByteBufferGuard ( resourceDescription , useUnmap ? CLEANER : null ) ) ; } }
creates an indexinput for the file with the given name .
