Package org.apache.lucene.util.automaton

Class CompiledAutomaton

java.lang.Object

org.apache.lucene.util.automaton.CompiledAutomaton

All Implemented Interfaces:

Accountable

public class CompiledAutomaton
extends Object
implements Accountable

Immutable class holding compiled details for a given Automaton. The Automaton is deterministic, must not have dead states but is not necessarily minimal.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CompiledAutomaton.AUTOMATON_TYPE	Automata are compiled into different internal forms for the most efficient execution depending upon the language they accept.

Field Summary

Fields

Modifier and Type	Field	Description
Automaton	automaton	Two dimensional array of transitions, indexed by state number for traversal.
BytesRef	commonSuffixRef	Shared common suffix accepted by the automaton.
Boolean	finite	Indicates if the automaton accepts a finite set of strings.
ByteRunAutomaton	runAutomaton	Matcher for quickly determining if a byte[] is accepted.
int	sinkState	Which state, if any, accepts all suffixes, else -1.
BytesRef	term	For CompiledAutomaton.AUTOMATON_TYPE.SINGLE this is the singleton term.
CompiledAutomaton.AUTOMATON_TYPE	type	If simplify is true this will be the "simplified" type; else, this is NORMAL

Constructor Summary

Constructors

Constructor	Description
CompiledAutomaton(Automaton automaton)	Create this, passing simplify=true and finite=null, so that we try to simplify the automaton and determine if it is finite.
CompiledAutomaton(Automaton automaton, Boolean finite, boolean simplify)	Create this.
CompiledAutomaton(Automaton automaton, Boolean finite, boolean simplify, int maxDeterminizedStates, boolean isBinary)	Create this.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
BytesRef	floor(BytesRef input, BytesRefBuilder output)	Finds largest term accepted by this Automaton, that's <= the provided input term.
TermsEnum	getTermsEnum(Terms terms)	Return a TermsEnum intersecting the provided Terms with the terms accepted by this automaton.
int	hashCode()
long	ramBytesUsed()	Return the memory usage of this object in bytes.
void	visit(QueryVisitor visitor, Query parent, String field)	Report back to a QueryVisitor how this automaton matches terms

Methods inherited from class java.lang.Object

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

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

getChildResources

Field Detail

type

public final CompiledAutomaton.AUTOMATON_TYPE type

If simplify is true this will be the "simplified" type; else, this is NORMAL

term

public final BytesRef term

For CompiledAutomaton.AUTOMATON_TYPE.SINGLE this is the singleton term.

runAutomaton

public final ByteRunAutomaton runAutomaton

Matcher for quickly determining if a byte[] is accepted. only valid for CompiledAutomaton.AUTOMATON_TYPE.NORMAL.

automaton

public final Automaton automaton

Two dimensional array of transitions, indexed by state number for traversal. The state numbering is consistent with runAutomaton. Only valid for CompiledAutomaton.AUTOMATON_TYPE.NORMAL.

commonSuffixRef

public final BytesRef commonSuffixRef

Shared common suffix accepted by the automaton. Only valid for CompiledAutomaton.AUTOMATON_TYPE.NORMAL, and only when the automaton accepts an infinite language. This will be null if the common prefix is length 0.

finite

public final Boolean finite

Indicates if the automaton accepts a finite set of strings. Null if this was not computed. Only valid for CompiledAutomaton.AUTOMATON_TYPE.NORMAL.

sinkState

public final int sinkState

Which state, if any, accepts all suffixes, else -1.

Constructor Detail

CompiledAutomaton

public CompiledAutomaton(Automaton automaton)

Create this, passing simplify=true and finite=null, so that we try to simplify the automaton and determine if it is finite.

CompiledAutomaton

public CompiledAutomaton(Automaton automaton,
                         Boolean finite,
                         boolean simplify)

Create this. If finite is null, we use Operations.isFinite(org.apache.lucene.util.automaton.Automaton) to determine whether it is finite. If simplify is true, we run possibly expensive operations to determine if the automaton is one the cases in CompiledAutomaton.AUTOMATON_TYPE.

CompiledAutomaton

public CompiledAutomaton(Automaton automaton,
                         Boolean finite,
                         boolean simplify,
                         int maxDeterminizedStates,
                         boolean isBinary)

Create this. If finite is null, we use Operations.isFinite(org.apache.lucene.util.automaton.Automaton) to determine whether it is finite. If simplify is true, we run possibly expensive operations to determine if the automaton is one the cases in CompiledAutomaton.AUTOMATON_TYPE. If simplify requires determinizing the automaton then only maxDeterminizedStates will be created. Any more than that will cause a TooComplexToDeterminizeException.

Method Detail

getTermsEnum

public TermsEnum getTermsEnum(Terms terms)
                       throws IOException

Return a TermsEnum intersecting the provided Terms with the terms accepted by this automaton.

Throws:

IOException

visit

public void visit(QueryVisitor visitor,
                  Query parent,
                  String field)

Report back to a QueryVisitor how this automaton matches terms

floor

public BytesRef floor(BytesRef input,
                      BytesRefBuilder output)

Finds largest term accepted by this Automaton, that's <= the provided input term. The result is placed in output; it's fine for output and input to point to the same bytes. The returned result is either the provided output, or null if there is no floor term (ie, the provided input term is before the first term accepted by this Automaton).

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class 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