code: public static IndexExpression readFrom(DataInput input) throws IOException
      {
          return new IndexExpression(ByteBufferUtil.readWithShortLength(input),
                                     Operator.readFrom(input),
                                     ByteBufferUtil.readWithShortLength(input));
      }
docs: Deserializes an <code>IndexExpression</code> instance from the specified input.
  
  @param input the input to read from
  @return the <code>IndexExpression</code> instance deserialized
  @throws IOException if a problem occurs while deserializing the <code>IndexExpression</code> instance.