org.apache.lucene.search.join

Class ToParentBlockJoinFieldComparator

java.lang.Object

org.apache.lucene.search.FieldComparator<Object>

org.apache.lucene.search.join.ToParentBlockJoinFieldComparator

Direct Known Subclasses:

ToParentBlockJoinFieldComparator.Highest, ToParentBlockJoinFieldComparator.Lowest

public abstract class ToParentBlockJoinFieldComparator
extends FieldComparator<Object>

A field comparator that allows parent documents to be sorted by fields from the nested / child documents.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ToParentBlockJoinFieldComparator.Highest Concrete implementation of ToParentBlockJoinSortField to sorts the parent docs with the highest values in the child / nested docs first.
static class	ToParentBlockJoinFieldComparator.Lowest Concrete implementation of ToParentBlockJoinSortField to sorts the parent docs with the lowest values in the child / nested docs first.

Nested classes/interfaces inherited from class org.apache.lucene.search.FieldComparator

FieldComparator.ByteComparator, FieldComparator.DocComparator, FieldComparator.DoubleComparator, FieldComparator.FloatComparator, FieldComparator.IntComparator, FieldComparator.LongComparator, FieldComparator.NumericComparator<T extends Number>, FieldComparator.RelevanceComparator, FieldComparator.ShortComparator, FieldComparator.TermOrdValComparator, FieldComparator.TermValComparator

Method Summary

Methods

Modifier and Type	Method and Description
int	compare(int slot1, int slot2) Compare hit at slot1 with hit at slot2.
void	setBottom(int slot) Set the bottom slot, ie the "weakest" (sorted last) entry in the queue.
FieldComparator<Object>	setNextReader(AtomicReaderContext context) Set a new AtomicReaderContext.
void	setTopValue(Object value) Record the top value, for future calls to FieldComparator.compareTop(int).
Object	value(int slot) Return the actual value in the slot.

Methods inherited from class org.apache.lucene.search.FieldComparator

compareBottom, compareTop, compareValues, copy, setScorer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

compare

public int compare(int slot1,
          int slot2)

Description copied from class: FieldComparator

Compare hit at slot1 with hit at slot2.

Specified by:

compare in class FieldComparator<Object>

Parameters:

slot1 - first slot to compare

slot2 - second slot to compare

Returns:

any N < 0 if slot2's value is sorted after slot1, any N > 0 if the slot2's value is sorted before slot1 and 0 if they are equal

setBottom

public void setBottom(int slot)

Description copied from class: FieldComparator

Set the bottom slot, ie the "weakest" (sorted last) entry in the queue. When FieldComparator.compareBottom(int) is called, you should compare against this slot. This will always be called before FieldComparator.compareBottom(int).

Specified by:

setBottom in class FieldComparator<Object>

Parameters:

slot - the currently weakest (sorted last) slot in the queue

setTopValue

public void setTopValue(Object value)

Description copied from class: FieldComparator

Record the top value, for future calls to FieldComparator.compareTop(int). This is only called for searches that use searchAfter (deep paging), and is called before any calls to FieldComparator.setNextReader(org.apache.lucene.index.AtomicReaderContext).

Specified by:

setTopValue in class FieldComparator<Object>

setNextReader

public FieldComparator<Object> setNextReader(AtomicReaderContext context)
                                      throws IOException

Description copied from class: FieldComparator

Set a new AtomicReaderContext. All subsequent docIDs are relative to the current reader (you must add docBase if you need to map it to a top-level docID).

Specified by:

setNextReader in class FieldComparator<Object>

Parameters:

context - current reader context

Returns:

the comparator to use for this segment; most comparators can just return "this" to reuse the same comparator across segments

Throws:

IOException - if there is a low-level IO error

value

public Object value(int slot)

Description copied from class: FieldComparator

Return the actual value in the slot.

Specified by:

value in class FieldComparator<Object>

Parameters:

slot - the value

Returns:

value in this slot