public abstract class

Spans

extends Object
java.lang.Object
   ↳ org.apache.lucene.search.spans.Spans
Known Direct Subclasses

Class Overview

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.

Summary

Public Constructors
Spans()
Public Methods
abstract int doc()
Returns the document number of the current match.
abstract int end()
Returns the end position of the current match.
abstract Collection<byte[]> getPayload()
Returns the payload data for the current span.
abstract boolean isPayloadAvailable()
Checks if a payload can be loaded at this position.
abstract boolean next()
Move to the next match, returning true iff any such exists.
abstract boolean skipTo(int target)
Skips to the first match beyond the current, whose document number is greater than or equal to target.
abstract int start()
Returns the start position of the current match.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public Spans ()

Public Methods

public abstract int doc ()

Returns the document number of the current match. Initially invalid.

public abstract int end ()

Returns the end position of the current match. Initially invalid.

public abstract Collection<byte[]> getPayload ()

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.

Returns
  • a List of byte arrays containing the data of this payload, otherwise null if isPayloadAvailable is false
Throws
IOException

public abstract boolean isPayloadAvailable ()

Checks if a payload can be loaded at this position.

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

Returns
  • true if there is a payload available at this position that can be loaded

public abstract boolean next ()

Move to the next match, returning true iff any such exists.

Throws
IOException

public abstract boolean skipTo (int target)

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.

Throws
IOException

public abstract int start ()

Returns the start position of the current match. Initially invalid.