Package org.apache.lucene.search

Class TermAutomatonQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.TermAutomatonQuery

All Implemented Interfaces:

Accountable

public class TermAutomatonQuery
extends Query
implements Accountable

A proximity query that lets you express an automaton, whose transitions are terms, to match documents. This is a generalization of other proximity queries like PhraseQuery, MultiPhraseQuery and SpanNearQuery. It is likely slow, since it visits any document having any of the terms (i.e. it acts like a disjunction, not a conjunction like PhraseQuery), and then it must merge-sort all positions within each document to test whether/how many times the automaton matches.

After creating the query, use createState(), setAccept(int, boolean), addTransition(int, int, java.lang.String) and addAnyTransition(int, int) to build up the automaton. Once you are done, call finish() and then execute the query.

This code is very new and likely has exciting bugs!

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	TermAutomatonQuery.EnumAndScorer
(package private) class	TermAutomatonQuery.TermAutomatonWeight

Field Summary

Fields

Modifier and Type	Field	Description
private int	anyTermID
private static long	BASE_RAM_BYTES
private Automaton.Builder	builder
(package private) Automaton	det
private java.lang.String	field
private java.util.Map<java.lang.Integer,BytesRef>	idToTerm
private java.util.Map<BytesRef,java.lang.Integer>	termToID

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
TermAutomatonQuery(java.lang.String field)

Method Summary

Modifier and Type	Method	Description
void	addAnyTransition(int source, int dest)	Adds a transition matching any term.
void	addTransition(int source, int dest, java.lang.String term)	Adds a transition to the automaton.
void	addTransition(int source, int dest, BytesRef term)	Adds a transition to the automaton.
private static boolean	checkFinished(TermAutomatonQuery q)
int	createState()	Returns a new state; state 0 is always the initial state.
Weight	createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)	Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(java.lang.Object other)	Returns true iff o is equal to this.
private boolean	equalsTo(TermAutomatonQuery other)
void	finish()	Call this once you are done adding states/transitions.
void	finish(int maxDeterminizedStates)	Call this once you are done adding states/transitions.
private int	getTermID(BytesRef term)
int	hashCode()	Override and implement query hash code properly in a subclass.
long	ramBytesUsed()	Return the memory usage of this object in bytes.
Query	rewrite(IndexReader reader)	Expert: called to re-write queries into primitive queries.
void	setAccept(int state, boolean accept)	Marks the specified state as accept or not.
java.lang.String	toDot()	Returns the dot (graphviz) representation of this automaton.
java.lang.String	toString(java.lang.String field)	Prints a query to a string, with field assumed to be the default field and omitted.
void	visit(QueryVisitor visitor)	Recurse through the query tree, visiting any child queries

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

classHash, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Field Detail

BASE_RAM_BYTES

private static final long BASE_RAM_BYTES

field

private final java.lang.String field

builder

private final Automaton.Builder builder

det

Automaton det

termToID

private final java.util.Map<BytesRef,java.lang.Integer> termToID

idToTerm

private final java.util.Map<java.lang.Integer,BytesRef> idToTerm

anyTermID

private int anyTermID

Constructor Detail

TermAutomatonQuery

public TermAutomatonQuery(java.lang.String field)

Method Detail

createState

public int createState()

Returns a new state; state 0 is always the initial state.

setAccept

public void setAccept(int state,
                      boolean accept)

Marks the specified state as accept or not.

addTransition

public void addTransition(int source,
                          int dest,
                          java.lang.String term)

Adds a transition to the automaton.

addTransition

public void addTransition(int source,
                          int dest,
                          BytesRef term)

Adds a transition to the automaton.

addAnyTransition

public void addAnyTransition(int source,
                             int dest)

Adds a transition matching any term.

finish

public void finish()

Call this once you are done adding states/transitions.

finish

public void finish(int maxDeterminizedStates)

Call this once you are done adding states/transitions.

Parameters:

maxDeterminizedStates - Maximum number of states created when determinizing the automaton. Higher numbers allow this operation to consume more memory but allow more complex automatons.

createWeight

public Weight createWeight(IndexSearcher searcher,
                           ScoreMode scoreMode,
                           float boost)
                    throws java.io.IOException

Description copied from class: Query

Expert: Constructs an appropriate Weight implementation for this query.

Only implemented by primitive queries, which re-write to themselves.

Overrides:

createWeight in class Query

scoreMode - How the produced scorers will be consumed.

boost - The boost that is propagated by the parent queries.

Throws:

java.io.IOException

toString

public java.lang.String toString(java.lang.String field)

Description copied from class: Query

Prints a query to a string, with field assumed to be the default field and omitted.

Specified by:

toString in class Query

getTermID

private int getTermID(BytesRef term)

equals

public boolean equals(java.lang.Object other)

Returns true iff o is equal to this.

Specified by:

equals in class Query

See Also:

Query.sameClassAs(Object), Query.classHash()

checkFinished

private static boolean checkFinished(TermAutomatonQuery q)

equalsTo

private boolean equalsTo(TermAutomatonQuery other)

hashCode

public int hashCode()

Description copied from class: Query

Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.

Specified by:

hashCode in class Query

See Also:

Query.equals(Object)

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable

toDot

public java.lang.String toDot()

Returns the dot (graphviz) representation of this automaton. This is extremely useful for visualizing the automaton.

rewrite

public Query rewrite(IndexReader reader)
              throws java.io.IOException

Description copied from class: Query

Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Overrides:

rewrite in class Query

Throws:

java.io.IOException

visit

public void visit(QueryVisitor visitor)

Description copied from class: Query

Recurse through the query tree, visiting any child queries

Overrides:

visit in class Query

Parameters:

visitor - a QueryVisitor to be called by each query in the tree