Package org.antlr.v4.runtime.atn

Class ATNConfigSet

java.lang.Object

org.antlr.v4.runtime.atn.ATNConfigSet

All Implemented Interfaces:

Iterable<ATNConfig>, Collection<ATNConfig>, Set<ATNConfig>

Direct Known Subclasses:

OrderedATNConfigSet

public class ATNConfigSet
extends Object
implements Set<ATNConfig>

Represents a set of ATN configurations (see ATNConfig). As configurations are added to the set, they are merged with other ATNConfig instances already in the set when possible using the graph-structured stack.

An instance of this class represents the complete set of positions (with context) in an ATN which would be associated with a single DFA state. Its internal representation is more complex than traditional state used for NFA to DFA conversion due to performance requirements (both improving speed and reducing memory overhead) as well as supporting features such as semantic predicates and non-greedy operators in a form to support ANTLR's prediction algorithm.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private final class	ATNConfigSet.ATNConfigSetIterator

Field Summary

Fields

Modifier and Type	Field	Description
private int	cachedHashCode
private final ArrayList<ATNConfig>	configs	This is a list of all configs in this set.
private ConflictInfo	conflictInfo
private boolean	dipsIntoOuterContext
private boolean	hasSemanticContext
private final HashMap<Long,ATNConfig>	mergedConfigs	This maps (state, alt) -> merged ATNConfig.
private boolean	outermostConfigSet	When true, this config set represents configurations where the entire outer context has been consumed by the ATN interpreter.
private int	uniqueAlt
private final ArrayList<ATNConfig>	unmerged	This is an "overflow" list holding configs which cannot be merged with one of the configs in mergedConfigs but have a colliding key.

Constructor Summary

Constructors

Modifier	Constructor	Description
	ATNConfigSet()
protected	ATNConfigSet(ATNConfigSet set, boolean readonly)

Method Summary

Modifier and Type	Method	Description
boolean	add(ATNConfig e)
boolean	add(ATNConfig e, PredictionContextCache contextCache)
boolean	addAll(Collection<? extends ATNConfig> c)
boolean	addAll(Collection<? extends ATNConfig> c, PredictionContextCache contextCache)
protected boolean	canMerge(ATNConfig left, long leftKey, ATNConfig right)
void	clear()
void	clearExplicitSemanticContext()
ATNConfigSet	clone(boolean readonly)
boolean	contains(Object o)
boolean	containsAll(Collection<?> c)
protected final void	ensureWritable()
boolean	equals(Object obj)
ATNConfig	get(int index)
ConflictInfo	getConflictInfo()
BitSet	getConflictingAlts()
boolean	getDipsIntoOuterContext()
protected long	getKey(ATNConfig e)
BitSet	getRepresentedAlternatives()	Get the set of all alternatives represented by configurations in this set.
Set<ATNState>	getStates()
int	getUniqueAlt()
int	hashCode()
boolean	hasSemanticContext()
boolean	isEmpty()
boolean	isExactConflict()
boolean	isOutermostConfigSet()
final boolean	isReadOnly()
Iterator<ATNConfig>	iterator()
void	markExplicitSemanticContext()
void	optimizeConfigs(ATNSimulator interpreter)
void	remove(int index)
boolean	remove(Object o)
boolean	removeAll(Collection<?> c)
boolean	retainAll(Collection<?> c)
void	setConflictInfo(ConflictInfo conflictInfo)
void	setOutermostConfigSet(boolean outermostConfigSet)
int	size()
Object[]	toArray()
<T> T[]	toArray(T[] a)
String	toString()
String	toString(boolean showContext)
private void	updatePropertiesForAddedConfig(ATNConfig config)
private void	updatePropertiesForMergedConfig(ATNConfig config)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

spliterator

Field Details

mergedConfigs

private final HashMap<Long,ATNConfig> mergedConfigs

This maps (state, alt) -> merged ATNConfig. The key does not account for the ATNConfig.getSemanticContext() of the value, which is only a problem if a single ATNConfigSet contains two configs with the same state and alternative but different semantic contexts. When this case arises, the first config added to this map stays, and the remaining configs are placed in unmerged.

This map is only used for optimizing the process of adding configs to the set, and is null for read-only sets stored in the DFA.

unmerged

private final ArrayList<ATNConfig> unmerged

This is an "overflow" list holding configs which cannot be merged with one of the configs in mergedConfigs but have a colliding key. This occurs when two configs in the set have the same state and alternative but different semantic contexts.

This list is only used for optimizing the process of adding configs to the set, and is null for read-only sets stored in the DFA.

configs

private final ArrayList<ATNConfig> configs

This is a list of all configs in this set.

uniqueAlt

private int uniqueAlt

conflictInfo

private ConflictInfo conflictInfo

hasSemanticContext

private boolean hasSemanticContext

dipsIntoOuterContext

private boolean dipsIntoOuterContext

outermostConfigSet

private boolean outermostConfigSet

When true, this config set represents configurations where the entire outer context has been consumed by the ATN interpreter. This prevents the ParserATNSimulator.closure(org.antlr.v4.runtime.atn.ATNConfigSet, org.antlr.v4.runtime.atn.ATNConfigSet, boolean, boolean, org.antlr.v4.runtime.atn.PredictionContextCache, boolean) from pursuing the global FOLLOW when a rule stop state is reached with an empty prediction context.

Note: outermostConfigSet and dipsIntoOuterContext should never be true at the same time.

cachedHashCode

private int cachedHashCode

Constructor Details

ATNConfigSet

public ATNConfigSet()

ATNConfigSet

protected ATNConfigSet(ATNConfigSet set,
 boolean readonly)

Method Details

getRepresentedAlternatives

@NotNull
public BitSet getRepresentedAlternatives()

Get the set of all alternatives represented by configurations in this set.

isReadOnly

public final boolean isReadOnly()

isOutermostConfigSet

public boolean isOutermostConfigSet()

setOutermostConfigSet

public void setOutermostConfigSet(boolean outermostConfigSet)

getStates

public Set<ATNState> getStates()

optimizeConfigs

public void optimizeConfigs(ATNSimulator interpreter)

clone

public ATNConfigSet clone(boolean readonly)

size

public int size()

Specified by:

size in interface Collection<ATNConfig>

Specified by:

size in interface Set<ATNConfig>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<ATNConfig>

Specified by:

isEmpty in interface Set<ATNConfig>

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<ATNConfig>

Specified by:

contains in interface Set<ATNConfig>

iterator

public Iterator<ATNConfig> iterator()

Specified by:

iterator in interface Collection<ATNConfig>

Specified by:

iterator in interface Iterable<ATNConfig>

Specified by:

iterator in interface Set<ATNConfig>

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<ATNConfig>

Specified by:

toArray in interface Set<ATNConfig>

toArray

public <T> T[] toArray(T[] a)

Specified by:

toArray in interface Collection<ATNConfig>

Specified by:

toArray in interface Set<ATNConfig>

add

public boolean add(ATNConfig e)

Specified by:

add in interface Collection<ATNConfig>

Specified by:

add in interface Set<ATNConfig>

add

public boolean add(ATNConfig e,
 @Nullable
 PredictionContextCache contextCache)

updatePropertiesForMergedConfig

private void updatePropertiesForMergedConfig(ATNConfig config)

updatePropertiesForAddedConfig

private void updatePropertiesForAddedConfig(ATNConfig config)

canMerge

protected boolean canMerge(ATNConfig left,
 long leftKey,
 ATNConfig right)

getKey

protected long getKey(ATNConfig e)

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<ATNConfig>

Specified by:

remove in interface Set<ATNConfig>

containsAll

public boolean containsAll(Collection<?> c)

Specified by:

containsAll in interface Collection<ATNConfig>

Specified by:

containsAll in interface Set<ATNConfig>

addAll

public boolean addAll(Collection<? extends ATNConfig> c)

Specified by:

addAll in interface Collection<ATNConfig>

Specified by:

addAll in interface Set<ATNConfig>

addAll

public boolean addAll(Collection<? extends ATNConfig> c,
 PredictionContextCache contextCache)

retainAll

public boolean retainAll(Collection<?> c)

Specified by:

retainAll in interface Collection<ATNConfig>

Specified by:

retainAll in interface Set<ATNConfig>

removeAll

public boolean removeAll(Collection<?> c)

Specified by:

removeAll in interface Collection<ATNConfig>

Specified by:

removeAll in interface Set<ATNConfig>

clear

public void clear()

Specified by:

clear in interface Collection<ATNConfig>

Specified by:

clear in interface Set<ATNConfig>

equals

public boolean equals(Object obj)

Specified by:

equals in interface Collection<ATNConfig>

Specified by:

equals in interface Set<ATNConfig>

Overrides:

equals in class Object

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection<ATNConfig>

Specified by:

hashCode in interface Set<ATNConfig>

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

toString

public String toString(boolean showContext)

getUniqueAlt

public int getUniqueAlt()

hasSemanticContext

public boolean hasSemanticContext()

clearExplicitSemanticContext

public void clearExplicitSemanticContext()

markExplicitSemanticContext

public void markExplicitSemanticContext()

getConflictInfo

public ConflictInfo getConflictInfo()

setConflictInfo

public void setConflictInfo(ConflictInfo conflictInfo)

getConflictingAlts

public BitSet getConflictingAlts()

isExactConflict

public boolean isExactConflict()

getDipsIntoOuterContext

public boolean getDipsIntoOuterContext()

get

public ATNConfig get(int index)

remove

public void remove(int index)

ensureWritable

protected final void ensureWritable()