Package eu.bandm.tools.util.multi

Class MapMultimap<A,B>

java.lang.Object

eu.bandm.tools.util.multi.MapMultimap<A,B>

Type Parameters:

A - type of the domain elements

B - type of the range elements

All Implemented Interfaces:

Multimap<A,B>, Serializable, Iterable<Map.Entry<A,B>>, Collection<Map.Entry<A,B>>, BiPredicate<A,B>, Set<Map.Entry<A,B>>

Direct Known Subclasses:

HashMultimap

public abstract class MapMultimap<A,B>
extends Object
implements Multimap<A,B>, Serializable

Generic implementation using maps of sets in both directions. The particular kind (implementation) of the maps is determined by the subclasses.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<B,Set<A>>	backward	The map from all contained range elements to the set of domain elements which point to it.
protected final Map<A,Set<B>>	forward	The map from all contained domain elements to the set of range elements which point to it.
protected int	size	The number of pairs currently realized by this instance.

Fields inherited from interface eu.bandm.tools.util.multi.Multimap

DEFAULT_PAIR_FORMAT_STRING

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MapMultimap(Map<A,Set<B>> forward, Map<B,Set<A>> backward, int size)	May not be called by the user.

Method Summary

Modifier and Type	Method	Description
boolean	add(A a, B b)	Adds a pair to this multimap.
final boolean	add(Map.Entry<A,B> e)
void	clear()
boolean	contains(A a, B b)	Whether this multimap contains a pair with the given components.
boolean	contains(Object o)
protected abstract Set<A>	createBackwardSet()	Creates the preimage set for every range element added.
protected abstract Set<B>	createForwardSet()	Creates the image set for every domain element added.
Set<A>	domain()	Returns the set of left components of pairs in this multimap.
Set<B>	image(A a)	Returns the set of right components of pairs with a given left component in this multimap.
Map<A,Set<B>>	imageMap()	Returns a map which maps each A which appears as a left component to a set of all B which appear as its right component.
Set<B>	imageUnchecked(Object a)	Convenience method for untyped inquiry.
boolean	isEmpty()
Iterator<Map.Entry<A,B>>	iterator()
Set<A>	preimage(B b)	Returns the set of left components of pairs with a given right component in this multimap.
Map<B,Set<A>>	preimageMap()	Returns a map which maps each B which appears as a right component to a set of all A which appear as its left component.
Set<A>	preimageUnchecked(Object b)	Convenience method for untyped inquiry.
Set<B>	range()	Returns the set of right components of pairs in this multimap.
boolean	remove(A a, B b)	Removes a pair from this multimap.
boolean	remove(Object o)
boolean	removeAllDomain(Collection<? extends A> c)	Removes all pairs with a left component in the given collection from this multimap.
boolean	removeAllRange(Collection<? extends B> c)	Removes all pairs with a right component in the given collection from this multimap.
boolean	removeDomain(A a)	Removes all pairs with a given left component from this multimap.
boolean	removeRange(B b)	Removes all pairs with a given right component from this multimap.
boolean	retainAllDomain(Collection<? extends A> c)	Removes from this multimap all pairs with a left component which is not in the given collection.
boolean	retainAllRange(Collection<? extends B> c)	Removes from this multimap all pairs with a right component which is not in the given collection.
int	size()
String	toString()	Returns a string representation of this instance.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.function.BiPredicate

and, negate, or

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface eu.bandm.tools.util.multi.Multimap

addAll, containsAll, containsUnchecked, imageAll, imageAllUnchecked, preimageAll, preimageAllUnchecked, removeAll, removeAllDomainUnchecked, removeAllRangeUnchecked, removeDomainUnchecked, removeRangeUnchecked, removeUnchecked, retainAll, retainAllDomainUnchecked, retainAllRangeUnchecked, test, toArray, toArray, toString, toString

Methods inherited from interface java.util.Set

equals, hashCode, spliterator

Field Details

forward

protected final Map<A,Set<B>> forward

The map from all contained domain elements to the set of range elements which point to it. These sets are never empty.

backward

protected final Map<B,Set<A>> backward

The map from all contained range elements to the set of domain elements which point to it. These sets are never empty.

size

protected int size

The number of pairs currently realized by this instance.

Constructor Details

MapMultimap

protected MapMultimap(Map<A,Set<B>> forward,
 Map<B,Set<A>> backward,
 int size)

May not be called by the user. May only called by constructors of subclasses, because all arguments must be in a consistent state.

Parameters:

forward - the map from domain elements to sets of range elements.

backward - the map from range elements to sets of domain elements.

size - the element pairs contained in the state defined by the given maps.

Method Details

createForwardSet

protected abstract Set<B> createForwardSet()

Creates the image set for every domain element added.

Subclasses implementing this method must ensure that when the map A->Set<B> is sorted, then this set also is.

Returns:

a sets for range domain elements assigned to one particular domain element.

createBackwardSet

protected abstract Set<A> createBackwardSet()

Creates the preimage set for every range element added.

Subclasses implementing this method must ensure that when the map B->Set<A> is sorted, then this set also is.

Returns:

a sets for the domain elements assigned to one particular range element.

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<A>

Specified by:

isEmpty in interface Set<A>

add

public final boolean add(Map.Entry<A,B> e)

This implementation calls add(Object,Object), because individual map entries are not used to hold pairs.

Specified by:

add in interface Collection<A>

Specified by:

add in interface Set<A>

add

public boolean add(A a,
 B b)

Adds a pair to this multimap. This operation must be stable: adding a pair that equals any pair contained in this multimap componentwise must not change this multimap.

This implementation works directly on internal maps of sets, and is the only way to actually effect the adding. Subclasses should override this method only to impose additional checks.

Specified by:

add in interface Multimap<A,B>

Parameters:

a - the left component of the pair to add

b - the right component of the pair to add

Returns:

whether this multimap has been changed by this operation

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<A>

Specified by:

remove in interface Set<A>

remove

public boolean remove(A a,
 B b)

Description copied from interface: Multimap

Removes a pair from this multimap. Removing a pair that equals no pair contained in this multimap componentwise must not change this multimap.

Specified by:

remove in interface Multimap<A,B>

Parameters:

a - the left component of the pair to remove.

b - the right component of the pair to remove.

Returns:

whether this multimap has been changed by this operation

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<A>

Specified by:

contains in interface Set<A>

contains

public boolean contains(A a,
 B b)

Description copied from interface: Multimap

Whether this multimap contains a pair with the given components.

Specified by:

contains in interface Multimap<A,B>

Parameters:

a - the left component of the pair to add.

b - the right component of the pair to add.

Returns:

whether this multimap contains a pair with the given components.

domain

public Set<A> domain()

Description copied from interface: Multimap

Returns the set of left components of pairs in this multimap.

The returned set is backed by this multimap, such that changes to this multimap are reflected by the set. The behavior of modifications of this multimap concurrent to iteration of the set is unspecified.

If this multimap supports the removeDomain operation, then the returned set and its iterators must support the remove operation, and changes by these operations must be reflected by this multimap.

Specified by:

domain in interface Multimap<A,B>

Returns:

the set of left components of pairs in this multimap.

range

public Set<B> range()

Description copied from interface: Multimap

Returns the set of right components of pairs in this multimap.

The returned set is backed by this multimap, such that changes to this multimap are reflected by the set. The behavior of modifications of this multimap concurrent to iteration of the set is unspecified.

If this multimap supports the removeRange operation, then the returned set and its iterators must support the remove operation, and changes by these operations must be reflected by this multimap.

Specified by:

range in interface Multimap<A,B>

Returns:

the set of right components of pairs in this multimap.

removeDomain

public boolean removeDomain(A a)

Description copied from interface: Multimap

Removes all pairs with a given left component from this multimap. The effect of the implementation on this multimap must be equivalent to the following code:

 removeDomain(final A a) {
   for (B b : new HashSet<B>(range())) remove(a, b) ;
 }
 

Specified by:

removeDomain in interface Multimap<A,B>

Parameters:

a - the left component of all pairs to remove.

Returns:

whether this multimap has been changed by this operation

removeRange

public boolean removeRange(B b)

Description copied from interface: Multimap

Removes all pairs with a given right component from this multimap. The effect of the implementation on this multimap must be equivalent to the following code:

 removeRange(final B b) {
   for (A a : new HashSet<A>(domain())) remove(a, b) ;
 }
 

Specified by:

removeRange in interface Multimap<A,B>

Parameters:

b - the right component of all pairs to remove.

Returns:

whether this multimap has been changed by this operation

removeAllDomain

public boolean removeAllDomain(Collection<? extends A> c)

Description copied from interface: Multimap

Removes all pairs with a left component in the given collection from this multimap.

Specified by:

removeAllDomain in interface Multimap<A,B>

Parameters:

c - the set of left component of all pairs to remove.

Returns:

whether this multimap has been changed by this operation

retainAllDomain

public boolean retainAllDomain(Collection<? extends A> c)

Description copied from interface: Multimap

Removes from this multimap all pairs with a left component which is not in the given collection.

Specified by:

retainAllDomain in interface Multimap<A,B>

Parameters:

c - the set of left component of all pairs not to remove.

Returns:

whether this multimap has been changed by this operation

removeAllRange

public boolean removeAllRange(Collection<? extends B> c)

Description copied from interface: Multimap

Removes all pairs with a right component in the given collection from this multimap.

Specified by:

removeAllRange in interface Multimap<A,B>

Parameters:

c - the set of the right component of all pairs to remove.

Returns:

whether this multimap has been changed by this operation

retainAllRange

public boolean retainAllRange(Collection<? extends B> c)

Description copied from interface: Multimap

Removes from this multimap all pairs with a right component which is not in the given collection.

Specified by:

retainAllRange in interface Multimap<A,B>

Parameters:

c - the set of the right component of all pairs not emove.

Returns:

whether this multimap has been changed by this operation

image

public Set<B> image(A a)

Description copied from interface: Multimap

Returns the set of right components of pairs with a given left component in this multimap.

The returned set need not be modifiable. The behaviour of this multimap after successfully modifying the returned set is unspecified.

Specified by:

image in interface Multimap<A,B>

Parameters:

a - a left component.

Returns:

the set of right components of pairs with a left component that equals(a) in this multimap.

imageUnchecked

public Set<B> imageUnchecked(Object a)

Description copied from interface: Multimap

Convenience method for untyped inquiry.

Specified by:

imageUnchecked in interface Multimap<A,B>

Parameters:

a - a left component.

Returns:

the set of right components of pairs with a left component that equals(a) in this multimap.

See Also:

• Multimap.image(A)

imageMap

public Map<A,Set<B>> imageMap()

Description copied from interface: Multimap

Returns a map which maps each A which appears as a left component to a set of all B which appear as its right component. The result is backed by the argument. Subsequent changes to either Collection are reflected by the other.

Specified by:

imageMap in interface Multimap<A,B>

Returns:

a map which maps each A which appears as a left component to a set of all B which appear as its right component.

preimage

public Set<A> preimage(B b)

Description copied from interface: Multimap

Returns the set of left components of pairs with a given right component in this multimap.

The returned set need not be modifiable. The behaviour of this multimap after successfully modifying the returned set is unspecified.

Specified by:

preimage in interface Multimap<A,B>

Parameters:

b - a right component.

Returns:

the set of left components of pairs with a right component that equals(b) in this multimap.

preimageUnchecked

public Set<A> preimageUnchecked(Object b)

Description copied from interface: Multimap

Convenience method for untyped inquiry.

Specified by:

preimageUnchecked in interface Multimap<A,B>

Parameters:

b - a right component.

Returns:

the set of left components of pairs with a right component that equals(b) in this multimap.

See Also:

• Multimap.preimage(B)

preimageMap

public Map<B,Set<A>> preimageMap()

Description copied from interface: Multimap

Returns a map which maps each B which appears as a right component to a set of all A which appear as its left component. The result is backed by the argument. Subsequent changes to either Collection are reflected by the other.

Specified by:

preimageMap in interface Multimap<A,B>

Returns:

a map which maps each B which appears as a right component to a set of all A which appear as its left component.

clear

public void clear()

Specified by:

clear in interface Collection<A>

Specified by:

clear in interface Set<A>

size

public int size()

Specified by:

size in interface Collection<A>

Specified by:

size in interface Set<A>

iterator

public Iterator<Map.Entry<A,B>> iterator()

Specified by:

iterator in interface Collection<A>

Specified by:

iterator in interface Iterable<A>

Specified by:

iterator in interface Set<A>

toString

public String toString()

Returns a string representation of this instance. Calls Multimap.toString(String) with Multimap.DEFAULT_PAIR_FORMAT_STRING.

Overrides:

toString in class Object