Package org.apache.lucene.search

Class LongValuesSource

java.lang.Object

org.apache.lucene.search.LongValuesSource

All Implemented Interfaces:

SegmentCacheable

public abstract class LongValuesSource
extends Object
implements SegmentCacheable

Base class for producing LongValues To obtain a LongValues object for a leaf reader, clients should call rewrite(IndexSearcher) against the top-level searcher, and then getValues(LeafReaderContext, DoubleValues). LongValuesSource objects for long and int-valued NumericDocValues fields can be obtained by calling fromLongField(String) and fromIntField(String). To obtain a LongValuesSource from a float or double-valued NumericDocValues field, use DoubleValuesSource.fromFloatField(String) or DoubleValuesSource.fromDoubleField(String) and then call DoubleValuesSource.toLongValuesSource().

Constructor Summary

Constructors

Constructor	Description
LongValuesSource()

Method Summary

Modifier and Type	Method	Description
static LongValuesSource	constant(long value)	Creates a LongValuesSource that always returns a constant value
abstract boolean	equals(Object obj)
static LongValuesSource	fromIntField(String field)	Creates a LongValuesSource that wraps an int-valued field
static LongValuesSource	fromLongField(String field)	Creates a LongValuesSource that wraps a long-valued field
SortField	getSortField(boolean reverse)	Create a sort field based on the value of this producer
abstract LongValues	getValues(LeafReaderContext ctx, DoubleValues scores)	Returns a LongValues instance for the passed-in LeafReaderContext and scores If scores are not needed to calculate the values (ie returns false, callers may safely pass null for the scores parameter.
abstract int	hashCode()
abstract boolean	needsScores()	Return true if document scores are needed to calculate values
abstract LongValuesSource	rewrite(IndexSearcher searcher)	Return a LongValuesSource specialised for the given IndexSearcher Implementations should assume that this will only be called once.
DoubleValuesSource	toDoubleValuesSource()	Convert to a DoubleValuesSource by casting long values to doubles
abstract String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.lucene.search.SegmentCacheable

isCacheable

Constructor Detail

LongValuesSource

public LongValuesSource()

Method Detail

getValues

public abstract LongValues getValues(LeafReaderContext ctx,
                                     DoubleValues scores)
                              throws IOException

Returns a LongValues instance for the passed-in LeafReaderContext and scores If scores are not needed to calculate the values (ie returns false, callers may safely pass null for the scores parameter.

Throws:

IOException

needsScores

public abstract boolean needsScores()

Return true if document scores are needed to calculate values

hashCode

public abstract int hashCode()

Overrides:

hashCode in class Object

equals

public abstract boolean equals(Object obj)

Overrides:

equals in class Object

toString

public abstract String toString()

Overrides:

toString in class Object

rewrite

public abstract LongValuesSource rewrite(IndexSearcher searcher)
                                  throws IOException

Return a LongValuesSource specialised for the given IndexSearcher Implementations should assume that this will only be called once. IndexSearcher-independent implementations can just return this

Throws:

IOException

getSortField

public SortField getSortField(boolean reverse)

Create a sort field based on the value of this producer

Parameters:

reverse - true if the sort should be decreasing

toDoubleValuesSource

public DoubleValuesSource toDoubleValuesSource()

Convert to a DoubleValuesSource by casting long values to doubles

fromLongField

public static LongValuesSource fromLongField(String field)

Creates a LongValuesSource that wraps a long-valued field

fromIntField

public static LongValuesSource fromIntField(String field)

Creates a LongValuesSource that wraps an int-valued field

constant

public static LongValuesSource constant(long value)

Creates a LongValuesSource that always returns a constant value