skipTo使用的是terms,这里面用到了大量的clone

[muyannian]

  public boolean skipTo(Term target) throws IOException {
    // already here
    if (t != null && t.equals(target)) return true;

    int startIdx = Arrays.binarySearch(tindex.index,target.text());

    if (startIdx >= 0) {
      // we hit the term exactly... lucky us!
      if (tenum != null) tenum.close();
      tenum = reader.terms(target);
      pos = startIdx << tindex.intervalBits;
      return setTerm();
    }

    // we didn't hit the term exactly
    startIdx=-startIdx-1;

    if (startIdx == 0) {
      // our target occurs *before* the first term
      if (tenum != null) tenum.close();
      tenum = reader.terms(target);
      pos = 0;
      return setTerm();
    } 

/** Returns an enumeration of terms starting at or after the named term. */
public SegmentTermEnum terms(Term term) throws IOException {
BytesRef termBytesRef = new BytesRef(term.text);
get(term, true, termBytesRef);
return (SegmentTermEnum)getThreadResources().termEnum.clone();
}

[muyannian]

用于从termNum to term的转换 不会造成太大的影响