Package org.apache.lucene.util.fst

Class Util.TopNSearcher<T>

java.lang.Object

org.apache.lucene.util.fst.Util.TopNSearcher<T>

Enclosing class:

Util

public static class Util.TopNSearcher<T>
extends java.lang.Object

Utility class to find top N shortest paths from start point(s).

Field Summary

Fields

Modifier and Type	Field	Description
private FST.BytesReader	bytesReader
private java.util.Comparator<T>	comparator
private FST<T>	fst
private int	maxQueueDepth
private java.util.Comparator<Util.FSTPath<T>>	pathComparator
(package private) java.util.TreeSet<Util.FSTPath<T>>	queue
private FST.Arc<T>	scratchArc
private int	topN

Constructor Summary

Constructors

Constructor	Description
TopNSearcher(FST<T> fst, int topN, int maxQueueDepth, java.util.Comparator<T> comparator)	Creates an unbounded TopNSearcher
TopNSearcher(FST<T> fst, int topN, int maxQueueDepth, java.util.Comparator<T> comparator, java.util.Comparator<Util.FSTPath<T>> pathComparator)

Method Summary

Modifier and Type	Method	Description
protected boolean	acceptPartialPath(Util.FSTPath<T> path)	Override this to prevent considering a path before it's complete
protected boolean	acceptResult(Util.FSTPath<T> path)
protected boolean	acceptResult(IntsRef input, T output)
protected void	addIfCompetitive(Util.FSTPath<T> path)
void	addStartPaths(FST.Arc<T> node, T startOutput, boolean allowEmptyString, IntsRefBuilder input)
void	addStartPaths(FST.Arc<T> node, T startOutput, boolean allowEmptyString, IntsRefBuilder input, float boost, java.lang.CharSequence context, int payload)	Adds all leaving arcs, including 'finished' arc, if the node is final, from this node into the queue.
Util.TopResults<T>	search()

Methods inherited from class java.lang.Object

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

Field Detail

fst

private final FST<T> fst

bytesReader

private final FST.BytesReader bytesReader

topN

private final int topN

maxQueueDepth

private final int maxQueueDepth

scratchArc

private final FST.Arc<T> scratchArc

comparator

private final java.util.Comparator<T> comparator

pathComparator

private final java.util.Comparator<Util.FSTPath<T>> pathComparator

queue

java.util.TreeSet<Util.FSTPath<T>> queue

Constructor Detail

TopNSearcher

public TopNSearcher(FST<T> fst,
                    int topN,
                    int maxQueueDepth,
                    java.util.Comparator<T> comparator)

Creates an unbounded TopNSearcher

Parameters:

fst - the FST to search on

topN - the number of top scoring entries to retrieve

maxQueueDepth - the maximum size of the queue of possible top entries

comparator - the comparator to select the top N

TopNSearcher

public TopNSearcher(FST<T> fst,
                    int topN,
                    int maxQueueDepth,
                    java.util.Comparator<T> comparator,
                    java.util.Comparator<Util.FSTPath<T>> pathComparator)

Method Detail

addIfCompetitive

protected void addIfCompetitive(Util.FSTPath<T> path)

addStartPaths

public void addStartPaths(FST.Arc<T> node,
                          T startOutput,
                          boolean allowEmptyString,
                          IntsRefBuilder input)
                   throws java.io.IOException

Throws:

java.io.IOException

addStartPaths

public void addStartPaths(FST.Arc<T> node,
                          T startOutput,
                          boolean allowEmptyString,
                          IntsRefBuilder input,
                          float boost,
                          java.lang.CharSequence context,
                          int payload)
                   throws java.io.IOException

Adds all leaving arcs, including 'finished' arc, if the node is final, from this node into the queue.

Throws:

java.io.IOException

search

public Util.TopResults<T> search()
                          throws java.io.IOException

Throws:

java.io.IOException

acceptResult

protected boolean acceptResult(Util.FSTPath<T> path)

acceptPartialPath

protected boolean acceptPartialPath(Util.FSTPath<T> path)

Override this to prevent considering a path before it's complete

acceptResult

protected boolean acceptResult(IntsRef input,
                               T output)