Package org.apache.lucene.util.fst

Class FSTEnum<T>

java.lang.Object

org.apache.lucene.util.fst.FSTEnum<T>

Direct Known Subclasses:

BytesRefFSTEnum, IntsRefFSTEnum

abstract class FSTEnum<T>
extends java.lang.Object

Can next() and advance() through the terms in an FST

Field Summary

Fields

Modifier and Type	Field	Description
protected FST.Arc<T>[]	arcs
protected FST<T>	fst
protected FST.BytesReader	fstReader
protected T	NO_OUTPUT
protected T[]	output
(package private) int	targetLength
protected int	upto

Constructor Summary

Constructors

Constructor	Description
FSTEnum(FST<T> fst)	doFloor controls the behavior of advance: if it's true doFloor is true, advance positions to the biggest term before target.

Method Summary

Modifier and Type	Method	Description
private FST.Arc<T>	backtrackToFloorArc(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)	Backtracks until it finds a node which first arc is before our target label.` Then on the node, finds the arc just before the targetLabel.
protected void	doNext()
protected void	doSeekCeil()	Seeks to smallest term that's >= target.
private FST.Arc<T>	doSeekCeilArrayDirectAddressing(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)
private FST.Arc<T>	doSeekCeilArrayPacked(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)
private FST.Arc<T>	doSeekCeilList(FST.Arc<T> arc, int targetLabel)
(package private) boolean	doSeekExact()	Seeks to exactly target term.
(package private) void	doSeekFloor()	Seeks to largest term that's <= target.
private FST.Arc<T>	doSeekFloorArrayDirectAddressing(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)
private FST.Arc<T>	doSeekFloorArrayPacked(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)
private FST.Arc<T>	doSeekFloorList(FST.Arc<T> arc, int targetLabel)
private void	findNextFloorArcBinarySearch(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)	Same as findNextFloorArcDirectAddressing(org.apache.lucene.util.fst.FST.Arc<T>, int, org.apache.lucene.util.fst.FST.BytesReader) for binary search node.
private void	findNextFloorArcDirectAddressing(FST.Arc<T> arc, int targetLabel, FST.BytesReader in)	Finds and reads an arc on the current node which label is strictly less than the given label.
private FST.Arc<T>	getArc(int idx)
protected abstract int	getCurrentLabel()
protected abstract int	getTargetLabel()
protected abstract void	grow()
private void	incr()
private void	pushFirst()
private void	pushLast()
private void	rewindPrefix()	Rewinds enum state to match the shared prefix between current term and target term
protected abstract void	setCurrentLabel(int label)

Methods inherited from class java.lang.Object

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

Field Detail

fst

protected final FST<T> fst

arcs

protected FST.Arc<T>[] arcs

output

protected T[] output

NO_OUTPUT

protected final T NO_OUTPUT

fstReader

protected final FST.BytesReader fstReader

upto

protected int upto

targetLength

int targetLength

Constructor Detail

FSTEnum

FSTEnum(FST<T> fst)

doFloor controls the behavior of advance: if it's true doFloor is true, advance positions to the biggest term before target.

Method Detail

getTargetLabel

protected abstract int getTargetLabel()

getCurrentLabel

protected abstract int getCurrentLabel()

setCurrentLabel

protected abstract void setCurrentLabel(int label)

grow

protected abstract void grow()

rewindPrefix

private void rewindPrefix()
                   throws java.io.IOException

Rewinds enum state to match the shared prefix between current term and target term

Throws:

java.io.IOException

doNext

protected void doNext()
               throws java.io.IOException

Throws:

java.io.IOException

doSeekCeil

protected void doSeekCeil()
                   throws java.io.IOException

Seeks to smallest term that's >= target.

Throws:

java.io.IOException

doSeekCeilArrayDirectAddressing

private FST.Arc<T> doSeekCeilArrayDirectAddressing(FST.Arc<T> arc,
                                                   int targetLabel,
                                                   FST.BytesReader in)
                                            throws java.io.IOException

Throws:

java.io.IOException

doSeekCeilArrayPacked

private FST.Arc<T> doSeekCeilArrayPacked(FST.Arc<T> arc,
                                         int targetLabel,
                                         FST.BytesReader in)
                                  throws java.io.IOException

Throws:

java.io.IOException

doSeekCeilList

private FST.Arc<T> doSeekCeilList(FST.Arc<T> arc,
                                  int targetLabel)
                           throws java.io.IOException

Throws:

java.io.IOException

doSeekFloor

void doSeekFloor()
          throws java.io.IOException

Seeks to largest term that's <= target.

Throws:

java.io.IOException

doSeekFloorArrayDirectAddressing

private FST.Arc<T> doSeekFloorArrayDirectAddressing(FST.Arc<T> arc,
                                                    int targetLabel,
                                                    FST.BytesReader in)
                                             throws java.io.IOException

Throws:

java.io.IOException

backtrackToFloorArc

private FST.Arc<T> backtrackToFloorArc(FST.Arc<T> arc,
                                       int targetLabel,
                                       FST.BytesReader in)
                                throws java.io.IOException

Backtracks until it finds a node which first arc is before our target label.` Then on the node, finds the arc just before the targetLabel.

Returns:

null to continue the seek floor recursion loop.

Throws:

java.io.IOException

findNextFloorArcDirectAddressing

private void findNextFloorArcDirectAddressing(FST.Arc<T> arc,
                                              int targetLabel,
                                              FST.BytesReader in)
                                       throws java.io.IOException

Finds and reads an arc on the current node which label is strictly less than the given label. Skips the first arc, finds next floor arc; or none if the floor arc is the first arc itself (in this case it has already been read).

Precondition: the given arc is the first arc of the node.

Throws:

java.io.IOException

findNextFloorArcBinarySearch

private void findNextFloorArcBinarySearch(FST.Arc<T> arc,
                                          int targetLabel,
                                          FST.BytesReader in)
                                   throws java.io.IOException

Same as findNextFloorArcDirectAddressing(org.apache.lucene.util.fst.FST.Arc<T>, int, org.apache.lucene.util.fst.FST.BytesReader) for binary search node.

Throws:

java.io.IOException

doSeekFloorArrayPacked

private FST.Arc<T> doSeekFloorArrayPacked(FST.Arc<T> arc,
                                          int targetLabel,
                                          FST.BytesReader in)
                                   throws java.io.IOException

Throws:

java.io.IOException

doSeekFloorList

private FST.Arc<T> doSeekFloorList(FST.Arc<T> arc,
                                   int targetLabel)
                            throws java.io.IOException

Throws:

java.io.IOException

doSeekExact

boolean doSeekExact()
             throws java.io.IOException

Seeks to exactly target term.

Throws:

java.io.IOException

incr

private void incr()

pushFirst

private void pushFirst()
                throws java.io.IOException

Throws:

java.io.IOException

pushLast

private void pushLast()
               throws java.io.IOException

Throws:

java.io.IOException

getArc

private FST.Arc<T> getArc(int idx)