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Home » lucene-3.0.1-src » org.apache » lucene » search » spans » [javadoc | source]
org.apache.lucene.search.spans
abstract public class: Spans [javadoc | source]
java.lang.Object
   org.apache.lucene.search.spans.Spans

Direct Known Subclasses:
    NearSpansUnordered, NearSpansOrdered, NearSpans, PayloadSpans, SpansCell, TermSpans, SpansCell

Expert: an enumeration of span matches. Used to implement span searching. Each span represents a range of term positions within a document. Matches are enumerated in order, by increasing document number, within that by increasing start position and finally by increasing end position.
Method from org.apache.lucene.search.spans.Spans Summary:
doc,   end,   getPayload,   isPayloadAvailable,   next,   skipTo,   start
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from org.apache.lucene.search.spans.Spans Detail:
 abstract public int doc()
    Returns the document number of the current match. Initially invalid.
 abstract public int end()
    Returns the end position of the current match. Initially invalid.
 abstract public Collection<byte> getPayload() throws IOException
    Returns the payload data for the current span. This is invalid until #next() is called for the first time. This method must not be called more than once after each call of #next() . However, most 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. An ordered SpanQuery does not lazy load, so if you have payloads in your index and you do not want ordered SpanNearQuerys to collect payloads, you can disable collection with a constructor option.

    Note that the return type is a collection, thus the ordering should not be relied upon.

    WARNING: The status of the Payloads feature is experimental. The APIs introduced here might change in the future and will not be supported anymore in such a case.

 abstract public boolean isPayloadAvailable()
    Checks if a payload can be loaded at this position.

    Payloads can only be loaded once per call to #next() .

 abstract public boolean next() throws IOException
    Move to the next match, returning true iff any such exists.
 abstract public boolean skipTo(int target) throws IOException
    Skips to the first match beyond the current, whose document number is greater than or equal to target.

    Returns true iff there is such a match.

    Behaves as if written:

      boolean skipTo(int target) {
        do {
          if (!next())
    	     return false;
        } while (target > doc());
        return true;
      }
    
    Most implementations are considerably more efficient than that.
 abstract public int start()
    Returns the start position of the current match. Initially invalid.