Top Description Inners Fields Constructors Methods
org.antlr.v4.runtime.atn

public Class ATNConfigSet

extends Object
implements Set<ATNConfig>
Class Inheritance
All Implemented Interfaces
java.util.Set, java.util.Collection, java.lang.Iterable
Known Direct Subclasses
org.antlr.v4.runtime.atn.OrderedATNConfigSet
Imports
org.antlr.v4.runtime.misc.NotNull, .Nullable, .Utils, java.util.ArrayList, .BitSet, .Collection, .Collections, .Comparator, .HashMap, .HashSet, .Iterator, .List, .NoSuchElementException, .Set

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.

Author
Sam Harwell

Nested and Inner Type Summary

Modifier and TypeClass and Description
private class

Field Summary

Modifier and TypeField and Description
private int
private final ArrayList<ATNConfig>
configs

This is a list of all configs in this set.

private ConflictInfo
private boolean
private boolean
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
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

AccessConstructor and Description
public
protected
ATNConfigSet(ATNConfigSet set, boolean readonly)

Method Summary

Modifier and TypeMethod and Description
public boolean
add(ATNConfig
element to be added to this set
e
)

Implements java.util.Set.add.

Adds the specified element to this set if it is not already present (optional operation).
public boolean
public boolean
addAll(Collection<? extends ATNConfig>
collection containing elements to be added to this set
c
)

Implements java.util.Set.addAll.

Adds all of the elements in the specified collection to this set if they're not already present (optional operation).
public boolean
addAll(Collection<? extends ATNConfig> c, PredictionContextCache contextCache)

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

public void
clear()

Implements java.util.Set.clear.

Removes all of the elements from this set (optional operation).
public void
public ATNConfigSet
clone(boolean readonly)

public boolean
contains(Object
element whose presence in this set is to be tested
o
)

Implements java.util.Set.contains.

Returns true if this set contains the specified element.
public boolean
containsAll(Collection<?>
collection to be checked for containment in this set
c
)

Implements java.util.Set.containsAll.

Returns true if this set contains all of the elements of the specified collection.
protected final void
public boolean
equals(Object
object to be compared for equality with this set
obj
)

Overrides java.lang.Object.equals.

Implements java.util.Set.equals.

Compares the specified object with this set for equality.
public ATNConfig
get(int index)

public ConflictInfo
public BitSet
public boolean
protected long
public BitSet
getRepresentedAlternatives()

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

public Set<ATNState>
public int
public int
hashCode()

Overrides java.lang.Object.hashCode.

Implements java.util.Set.hashCode.

Returns the hash code value for this set.
public boolean
public boolean
isEmpty()

Implements java.util.Set.isEmpty.

Returns true if this set contains no elements.
public boolean
public boolean
public final boolean
public Iterator<ATNConfig>
iterator()

Implements java.util.Set.iterator.

Returns an iterator over the elements in this set.
public void
public void
public boolean
remove(Object
object to be removed from this set, if present
o
)

Implements java.util.Set.remove.

Removes the specified element from this set if it is present (optional operation).
public void
remove(int index)

public boolean
removeAll(Collection<?>
collection containing elements to be removed from this set
c
)

Implements java.util.Set.removeAll.

Removes from this set all of its elements that are contained in the specified collection (optional operation).
public boolean
retainAll(Collection<?>
collection containing elements to be retained in this set
c
)

Implements java.util.Set.retainAll.

Retains only the elements in this set that are contained in the specified collection (optional operation).
public void
public void
setOutermostConfigSet(boolean outermostConfigSet)

public int
size()

Implements java.util.Set.size.

Returns the number of elements in this set (its cardinality).
public Object[]
toArray()

Implements java.util.Set.toArray.

Returns an array containing all of the elements in this set.
public <T> T[]
toArray(T[]
the array into which the elements of this set are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
a
)

Implements java.util.Set.toArray.

Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array.
public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.
public String
toString(boolean showContext)

private void
private void
Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

cachedHashCodeback to summary
private int cachedHashCode
configsback to summary
private final ArrayList<ATNConfig> configs

This is a list of all configs in this set.

conflictInfoback to summary
private ConflictInfo conflictInfo
dipsIntoOuterContextback to summary
private boolean dipsIntoOuterContext
hasSemanticContextback to summary
private boolean hasSemanticContext
mergedConfigsback to summary
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.

outermostConfigSetback to summary
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 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.

uniqueAltback to summary
private int uniqueAlt
unmergedback to summary
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.

Constructor Detail

ATNConfigSetback to summary
public ATNConfigSet()
ATNConfigSetback to summary
protected ATNConfigSet(ATNConfigSet set, boolean readonly)
Annotations
@SuppressWarnings:unchecked

Method Detail

addback to summary
public boolean add(ATNConfig e)

Implements java.util.Set.add.

Doc from java.util.Set.add.

Adds the specified element to this set if it is not already present (optional operation). More formally, adds the specified element e to this set if the set contains no element e2 such that Objects.equals(e, e2). If this set already contains the element, the call leaves the set unchanged and returns false. In combination with the restriction on constructors, this ensures that sets never contain duplicate elements.

The stipulation above does not imply that sets must accept all elements; sets may refuse to add any particular element, including null, and throw an exception, as described in the specification for Collection.add. Individual set implementations should clearly document any restrictions on the elements that they may contain.

Parameters
e:ATNConfig

element to be added to this set

Returns:boolean

true if this set did not already contain the specified element

Annotations
@Override
addback to summary
public boolean add(ATNConfig e, PredictionContextCache contextCache)
addAllback to summary
public boolean addAll(Collection<? extends ATNConfig> c)

Implements java.util.Set.addAll.

Doc from java.util.Set.addAll.

Adds all of the elements in the specified collection to this set if they're not already present (optional operation). If the specified collection is also a set, the addAll operation effectively modifies this set so that its value is the union of the two sets. The behavior of this operation is undefined if the specified collection is modified while the operation is in progress.

Parameters
c:Collection<? extends ATNConfig>

collection containing elements to be added to this set

Returns:boolean

true if this set changed as a result of the call

Annotations
@Override
addAllback to summary
public boolean addAll(Collection<? extends ATNConfig> c, PredictionContextCache contextCache)
canMergeback to summary
protected boolean canMerge(ATNConfig left, long leftKey, ATNConfig right)
clearback to summary
public void clear()

Implements java.util.Set.clear.

Doc from java.util.Set.clear.

Removes all of the elements from this set (optional operation). The set will be empty after this call returns.

Annotations
@Override
clearExplicitSemanticContextback to summary
public void clearExplicitSemanticContext()
cloneback to summary
public ATNConfigSet clone(boolean readonly)
containsback to summary
public boolean contains(Object o)

Implements java.util.Set.contains.

Doc from java.util.Set.contains.

Returns true if this set contains the specified element. More formally, returns true if and only if this set contains an element e such that Objects.equals(o, e).

Parameters
o:Object

element whose presence in this set is to be tested

Returns:boolean

true if this set contains the specified element

Annotations
@Override
containsAllback to summary
public boolean containsAll(Collection<?> c)

Implements java.util.Set.containsAll.

Doc from java.util.Set.containsAll.

Returns true if this set contains all of the elements of the specified collection. If the specified collection is also a set, this method returns true if it is a subset of this set.

Parameters
c:Collection<?>

collection to be checked for containment in this set

Returns:boolean

true if this set contains all of the elements of the specified collection

Annotations
@Override
ensureWritableback to summary
protected final void ensureWritable()
equalsback to summary
public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Implements java.util.Set.equals.

Doc from java.util.Set.equals.

Compares the specified object with this set for equality. Returns true if the specified object is also a set, the two sets have the same size, and every member of the specified set is contained in this set (or equivalently, every member of this set is contained in the specified set). This definition ensures that the equals method works properly across different implementations of the set interface.

Parameters
obj:Object

object to be compared for equality with this set

Returns:boolean

true if the specified object is equal to this set

Annotations
@Override
getback to summary
public ATNConfig get(int index)
getConflictInfoback to summary
public ConflictInfo getConflictInfo()
getConflictingAltsback to summary
public BitSet getConflictingAlts()
getDipsIntoOuterContextback to summary
public boolean getDipsIntoOuterContext()
getKeyback to summary
protected long getKey(ATNConfig e)
getRepresentedAlternativesback to summary
public BitSet getRepresentedAlternatives()

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

Annotations
@NotNull
getStatesback to summary
public Set<ATNState> getStates()
getUniqueAltback to summary
public int getUniqueAlt()
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Implements java.util.Set.hashCode.

Doc from java.util.Set.hashCode.

Returns the hash code value for this set. The hash code of a set is defined to be the sum of the hash codes of the elements in the set, where the hash code of a null element is defined to be zero. This ensures that s1.equals(s2) implies that s1.hashCode()==s2.hashCode() for any two sets s1 and s2, as required by the general contract of Object#hashCode.

Returns:int

the hash code value for this set

Annotations
@Override
hasSemanticContextback to summary
public boolean hasSemanticContext()
isEmptyback to summary
public boolean isEmpty()

Implements java.util.Set.isEmpty.

Doc from java.util.Set.isEmpty.

Returns true if this set contains no elements.

Returns:boolean

true if this set contains no elements

Annotations
@Override
isExactConflictback to summary
public boolean isExactConflict()
isOutermostConfigSetback to summary
public boolean isOutermostConfigSet()
isReadOnlyback to summary
public final boolean isReadOnly()
iteratorback to summary
public Iterator<ATNConfig> iterator()

Implements java.util.Set.iterator.

Doc from java.util.Set.iterator.

Returns an iterator over the elements in this set. The elements are returned in no particular order (unless this set is an instance of some class that provides a guarantee).

Returns:Iterator<ATNConfig>

an iterator over the elements in this set

Annotations
@Override
markExplicitSemanticContextback to summary
public void markExplicitSemanticContext()
optimizeConfigsback to summary
public void optimizeConfigs(ATNSimulator interpreter)
removeback to summary
public boolean remove(Object o)

Implements java.util.Set.remove.

Doc from java.util.Set.remove.

Removes the specified element from this set if it is present (optional operation). More formally, removes an element e such that Objects.equals(o, e), if this set contains such an element. Returns true if this set contained the element (or equivalently, if this set changed as a result of the call). (This set will not contain the element once the call returns.)

Parameters
o:Object

object to be removed from this set, if present

Returns:boolean

true if this set contained the specified element

Annotations
@Override
removeback to summary
public void remove(int index)
removeAllback to summary
public boolean removeAll(Collection<?> c)

Implements java.util.Set.removeAll.

Doc from java.util.Set.removeAll.

Removes from this set all of its elements that are contained in the specified collection (optional operation). If the specified collection is also a set, this operation effectively modifies this set so that its value is the asymmetric set difference of the two sets.

Parameters
c:Collection<?>

collection containing elements to be removed from this set

Returns:boolean

true if this set changed as a result of the call

Annotations
@Override
retainAllback to summary
public boolean retainAll(Collection<?> c)

Implements java.util.Set.retainAll.

Doc from java.util.Set.retainAll.

Retains only the elements in this set that are contained in the specified collection (optional operation). In other words, removes from this set all of its elements that are not contained in the specified collection. If the specified collection is also a set, this operation effectively modifies this set so that its value is the intersection of the two sets.

Parameters
c:Collection<?>

collection containing elements to be retained in this set

Returns:boolean

true if this set changed as a result of the call

Annotations
@Override
setConflictInfoback to summary
public void setConflictInfo(ConflictInfo conflictInfo)
setOutermostConfigSetback to summary
public void setOutermostConfigSet(boolean outermostConfigSet)
sizeback to summary
public int size()

Implements java.util.Set.size.

Doc from java.util.Set.size.

Returns the number of elements in this set (its cardinality). If this set contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Returns:int

the number of elements in this set (its cardinality)

Annotations
@Override
toArrayback to summary
public Object[] toArray()

Implements java.util.Set.toArray.

Doc from java.util.Set.toArray.

Returns an array containing all of the elements in this set. If this set makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

The returned array will be "safe" in that no references to it are maintained by this set. (In other words, this method must allocate a new array even if this set is backed by an array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Returns:Object[]

an array containing all the elements in this set

Annotations
@Override
toArrayback to summary
public <T> T[] toArray(T[] a)

Implements java.util.Set.toArray.

Doc from java.util.Set.toArray.

Returns an array containing all of the elements in this set; the runtime type of the returned array is that of the specified array. If the set fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this set.

If this set fits in the specified array with room to spare (i.e., the array has more elements than this set), the element in the array immediately following the end of the set is set to null. (This is useful in determining the length of this set only if the caller knows that this set does not contain any null elements.)

If this set makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

Like the toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.

Suppose x is a set known to contain only strings. The following code can be used to dump the set into a newly allocated array of String:

    String[] y = x.toArray(new String[0]);
Note that toArray(new Object[0]) is identical in function to toArray().
Parameters
<T>

Doc from java.util.Collection.toArray. the component type of the array to contain the collection

a:T[]

the array into which the elements of this set are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:T[]

an array containing all the elements in this set

Annotations
@Override
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations
@Override
toStringback to summary
public String toString(boolean showContext)
updatePropertiesForAddedConfigback to summary
private void updatePropertiesForAddedConfig(ATNConfig config)
updatePropertiesForMergedConfigback to summary
private void updatePropertiesForMergedConfig(ATNConfig config)
org.antlr.v4.runtime.atn back to summary

private final Class ATNConfigSet.ATNConfigSetIterator

extends Object
implements Iterator<ATNConfig>
Class Inheritance
All Implemented Interfaces
java.util.Iterator

Field Summary

Modifier and TypeField and Description
pack-priv int
pack-priv boolean

Constructor Summary

AccessConstructor and Description
private

Method Summary

Modifier and TypeMethod and Description
public boolean
hasNext()

Implements java.util.Iterator.hasNext.

Returns true if the iteration has more elements.
public ATNConfig
next()

Implements java.util.Iterator.next.

Returns the next element in the iteration.
public void
remove()

Overrides default java.util.Iterator.remove.

Removes from the underlying collection the last element returned by this iterator (optional operation).
Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

indexback to summary
pack-priv int index
removedback to summary
pack-priv boolean removed

Constructor Detail

ATNConfigSetIteratorback to summary
private ATNConfigSetIterator()

Method Detail

hasNextback to summary
public boolean hasNext()

Implements java.util.Iterator.hasNext.

Doc from java.util.Iterator.hasNext.

Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)

Returns:boolean

true if the iteration has more elements

Annotations
@Override
nextback to summary
public ATNConfig next()

Implements java.util.Iterator.next.

Doc from java.util.Iterator.next.

Returns the next element in the iteration.

Returns:ATNConfig

the next element in the iteration

Annotations
@Override
removeback to summary
public void remove()

Overrides default java.util.Iterator.remove.

Doc from java.util.Iterator.remove.

Removes from the underlying collection the last element returned by this iterator (optional operation). This method can be called only once per call to next.

The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method, unless an overriding class has specified a concurrent modification policy.

The behavior of an iterator is unspecified if this method is called after a call to the forEachRemaining method.

Annotations
@Override