How to use

copyFrom

method

in

org.apache.lucene.util.ByteBlockPool

/**
 * Returns the <i>n'th</i> element of this {@link BytesRefList}
 * @param spare a spare {@link BytesRef} instance
 * @param ord the elements ordinal to retrieve 
 * @return the <i>n'th</i> element of this {@link BytesRefList}
 */
public BytesRef get(BytesRef spare, int ord) {
 if (lastElement > ord) {
  spare.offset = offsets[ord];
  spare.length = ord == lastElement - 1 ? currentOffset - spare.offset
    : offsets[ord + 1] - spare.offset;
  pool.copyFrom(spare);
  return spare;
 }
 throw new IndexOutOfBoundsException("index " + ord
   + " must be less than the size: " + lastElement);
 
}