Add Payload retrieval to Spans

• Key: LUCENE-1001
• Type: New Feature
• Status: Closed
• Resolution: Fixed
• Priority: Minor
• Assignee: Grant Ingersoll
• Reporter: Grant Ingersoll
• Component/s: Search
• Fix Version/s: 2.4

Description

It will be nice to have access to payloads when doing SpanQuerys.

See http://www.gossamer-threads.com/lists/lucene/java-dev/52270 and http://www.gossamer-threads.com/lists/lucene/java-dev/51134

Current API, added to Spans.java is below. I will try to post a patch as soon as I can figure out how to make it work for unordered spans (I believe I have all the other cases working).

 /**
   * Returns the payload data for the current span.
   * This is invalid until {@link #next()} is called for
   * the first time.
   * This method must not be called more than once after each call
   * of {@link #next()}. However, payloads are loaded lazily,
   * so if the payload data for the current position is not needed,
   * this method may not be called at all for performance reasons.<br>
   * <br>
   * <p><font color="#FF0000">
   * WARNING: The status of the <b>Payloads</b> feature is experimental.
   * The APIs introduced here might change in the future and will not be
   * supported anymore in such a case.</font>
   *
   * @return a List of byte arrays containing the data of this payload
   * @throws IOException
   */
  // TODO: Remove warning after API has been finalized
  List/*<byte[]>*/ getPayload() throws IOException;

  /**
   * Checks if a payload can be loaded at this position.
   * <p/>
   * Payloads can only be loaded once per call to
   * {@link #next()}.
   * <p/>
   * <p><font color="#FF0000">
   * WARNING: The status of the <b>Payloads</b> feature is experimental.
   * The APIs introduced here might change in the future and will not be
   * supported anymore in such a case.</font>
   *
   * @return true if there is a payload available at this position that can be loaded
   */
  // TODO: Remove warning after API has been finalized
  public boolean isPayloadAvailable();