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 could either be deterministic or non-deterministic, For deterministic automaton, it must not have dead states but is not necessarily minimal. And will be executed using ByteRunAutomaton For non-deterministic automaton, it will be executed using NFARunAutomaton

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

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

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
CompiledAutomaton(Automaton automaton)	Create this, passing simplify=true, so that we try to simplify the automaton.
CompiledAutomaton(Automaton automaton, boolean finite, boolean simplify)	Create this.
CompiledAutomaton(Automaton automaton, boolean finite, boolean simplify, 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.
ByteRunnable	getByteRunnable()	Get a ByteRunnable instance, it will be different depending on whether a NFA or DFA is passed in, and does not guarantee returning non-null object
TermsEnum	getTermsEnum(Terms terms)	Return a TermsEnum intersecting the provided Terms with the terms accepted by this automaton.
TransitionAccessor	getTransitionAccessor()	Get a TransitionAccessor instance, it will be different depending on whether a NFA or DFA is passed in, and does not guarantee returning non-null object
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 Details

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. Only valid for CompiledAutomaton.AUTOMATON_TYPE.NORMAL.

sinkState

public final int sinkState

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

Constructor Details

CompiledAutomaton

public CompiledAutomaton(Automaton automaton)

Create this, passing simplify=true, so that we try to simplify the automaton.

CompiledAutomaton

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

Create this. If simplify is true, we run possibly expensive operations to determine if the automaton is one the cases in CompiledAutomaton.AUTOMATON_TYPE. Set finite to true if the automaton is finite, otherwise set to false if infinite or you don't know.

CompiledAutomaton

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

Create this. If simplify is true, we run possibly expensive operations to determine if the automaton is one the cases in CompiledAutomaton.AUTOMATON_TYPE. Set finite to true if the automaton is finite, otherwise set to false if infinite or you don't know.

Method Details

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).

getByteRunnable

public ByteRunnable getByteRunnable()

Get a ByteRunnable instance, it will be different depending on whether a NFA or DFA is passed in, and does not guarantee returning non-null object

getTransitionAccessor

public TransitionAccessor getTransitionAccessor()

Get a TransitionAccessor instance, it will be different depending on whether a NFA or DFA is passed in, and does not guarantee returning non-null object

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