Class Spans

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.

Inheritance
System.Object
Spans
NearSpansOrdered
NearSpansUnordered
SpanPositionCheckQuery.PositionCheckSpan
TermSpans
Namespace: Lucene.Net.Search.Spans
Assembly: Lucene.Net.dll
Syntax
public abstract class Spans : object

Properties

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Doc

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

Declaration
public abstract int Doc { get; }
Property Value
Type Description
System.Int32
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End

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

Declaration
public abstract int End { get; }
Property Value
Type Description
System.Int32
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IsPayloadAvailable

Checks if a payload can be loaded at this position.

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

Declaration
public abstract bool IsPayloadAvailable { get; }
Property Value
Type Description
System.Boolean

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

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Start

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

Declaration
public abstract int Start { get; }
Property Value
Type Description
System.Int32

Methods

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GetCost()

Returns the estimated cost of this spans.

This is generally an upper bound of the number of documents this iterator might match, but may be a rough heuristic, hardcoded value, or otherwise completely inaccurate.

Declaration
public abstract long GetCost()
Returns
Type Description
System.Int64
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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.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Declaration
public abstract ICollection<byte[]> GetPayload()
Returns
Type Description
ICollection<System.Byte[]>

A ICollection{byte[]} of byte arrays containing the data of this payload, otherwise null if IsPayloadAvailable is false

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Next()

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

Declaration
public abstract bool Next()
Returns
Type Description
System.Boolean
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SkipTo(Int32)

Skips to the first match beyond the current, whose document number is greater than or equal to target.

The behavior of this method is undefined when called with target <= current, or after the iterator has exhausted. Both cases may result in unpredicted behavior.

Returns true if there is such a match.

Behaves as if written: 

    bool SkipTo(int target) 
    {
        do 
        {
            if (!Next())
                return false;
        } while (target > Doc);
        return true;
    }

Most implementations are considerably more efficient than that.

Declaration
public abstract bool SkipTo(int target)
Parameters
Type Name Description
System.Int32 target
Returns
Type Description
System.Boolean