V
 the graph vertex typeE
 the graph edge typepublic abstract class AbstractBaseGraph<V,E> extends AbstractGraph<V,E> implements Graph<V,E>, Cloneable, Serializable
Graph
interface.
Its subclasses add various restrictions to get more specific graphs. The decision whether it is directed or undirected is decided at construction time and cannot be later modified (see constructor for details).
The behavior of this class can be adjusted by changing the GraphSpecificsStrategy
that is
provided from the constructor. All implemented strategies guarantee deterministic vertex and edge
set ordering (via LinkedHashMap
and LinkedHashSet
). The defaults are reasonable
for most usecases, only change if you know what you are doing.
DEFAULT_EDGE_WEIGHT
Modifier  Constructor and Description 

protected 
AbstractBaseGraph(Supplier<V> vertexSupplier,
Supplier<E> edgeSupplier,
GraphType type)
Construct a new graph.

protected 
AbstractBaseGraph(Supplier<V> vertexSupplier,
Supplier<E> edgeSupplier,
GraphType type,
GraphSpecificsStrategy<V,E> graphSpecificsStrategy)
Construct a new graph.

Modifier and Type  Method and Description 

E 
addEdge(V sourceVertex,
V targetVertex)
Creates a new edge in this graph, going from the source vertex to the target vertex, and
returns the created edge.

boolean 
addEdge(V sourceVertex,
V targetVertex,
E e)
Adds the specified edge to this graph, going from the source vertex to the target vertex.

V 
addVertex()
Creates a new vertex in this graph and returns it.

boolean 
addVertex(V v)
Adds the specified vertex to this graph if not already present.

Object 
clone()
Returns a shallow copy of this graph instance.

boolean 
containsEdge(E e)
Returns true if this graph contains the specified edge.

boolean 
containsVertex(V v)
Returns true if this graph contains the specified vertex.

int 
degreeOf(V vertex)
Returns the degree of the specified vertex.

Set<E> 
edgeSet()
Returns a set of the edges contained in this graph.

Set<E> 
edgesOf(V vertex)
Returns a set of all edges touching the specified vertex.

Set<E> 
getAllEdges(V sourceVertex,
V targetVertex)
Returns a set of all edges connecting source vertex to target vertex if such vertices exist
in this graph.

E 
getEdge(V sourceVertex,
V targetVertex)
Returns an edge connecting source vertex to target vertex if such vertices and such edge
exist in this graph.

V 
getEdgeSource(E e)
Returns the source vertex of an edge.

Supplier<E> 
getEdgeSupplier()
Return the edge supplier that the graph uses whenever it needs to create new edges.

V 
getEdgeTarget(E e)
Returns the target vertex of an edge.

double 
getEdgeWeight(E e)
Returns the weight assigned to a given edge.

GraphType 
getType()
Get the graph type.

Supplier<V> 
getVertexSupplier()
Return the vertex supplier that the graph uses whenever it needs to create new vertices.

Set<E> 
incomingEdgesOf(V vertex)
Returns a set of all edges incoming into the specified vertex.

int 
inDegreeOf(V vertex)
Returns the "in degree" of the specified vertex.

int 
outDegreeOf(V vertex)
Returns the "out degree" of the specified vertex.

Set<E> 
outgoingEdgesOf(V vertex)
Returns a set of all edges outgoing from the specified vertex.

boolean 
removeEdge(E e)
Removes the specified edge from the graph.

E 
removeEdge(V sourceVertex,
V targetVertex)
Removes an edge going from source vertex to target vertex, if such vertices and such edge
exist in this graph.

boolean 
removeVertex(V v)
Removes the specified vertex from this graph including all its touching edges if present.

void 
setEdgeSupplier(Supplier<E> edgeSupplier)
Set the edge supplier that the graph uses whenever it needs to create new edges.

void 
setEdgeWeight(E e,
double weight)
Set an edge weight.

void 
setVertexSupplier(Supplier<V> vertexSupplier)
Set the vertex supplier that the graph uses whenever it needs to create new vertices.

Set<V> 
vertexSet()
Returns a set of the vertices contained in this graph.

assertVertexExist, containsEdge, equals, hashCode, removeAllEdges, removeAllEdges, removeAllEdges, removeAllVertices, toString, toStringFromSets
finalize, getClass, notify, notifyAll, wait, wait, wait
containsEdge, removeAllEdges, removeAllEdges, removeAllVertices, setEdgeWeight
protected AbstractBaseGraph(Supplier<V> vertexSupplier, Supplier<E> edgeSupplier, GraphType type)
vertexSupplier
 the vertex supplier, can be nulledgeSupplier
 the edge supplier, can be nulltype
 the graph typeIllegalArgumentException
 if the graph type is mixedprotected AbstractBaseGraph(Supplier<V> vertexSupplier, Supplier<E> edgeSupplier, GraphType type, GraphSpecificsStrategy<V,E> graphSpecificsStrategy)
vertexSupplier
 the vertex supplier, can be nulledgeSupplier
 the edge supplier, can be nulltype
 the graph typegraphSpecificsStrategy
 strategy for constructing lowlevel graph specificsIllegalArgumentException
 if the graph type is mixedpublic Set<E> getAllEdges(V sourceVertex, V targetVertex)
null
, returns
null
. If both vertices exist but no edges found, returns an empty set.
In undirected graphs, some of the returned edges may have their source and target vertices in the opposite order. In simple graphs the returned set is either singleton set or empty set.
getAllEdges
in interface Graph<V,E>
sourceVertex
 source vertex of the edge.targetVertex
 target vertex of the edge.public Supplier<E> getEdgeSupplier()
Graph
A graph uses the edge supplier to create new edge objects whenever a user calls method
Graph.addEdge(Object, Object)
. Users can also create the edge in user code and then
use method Graph.addEdge(Object, Object, Object)
to add the edge.
In contrast with the Supplier
interface, the edge supplier has the additional
requirement that a new and distinct result is returned every time it is invoked. More
specifically for a new edge to be added in a graph e
must not be equal to
any other edge in the graph (even if the graph allows edgemultiplicity). More formally, the
graph must not contain any edge e2
such that e2.equals(e)
.
getEdgeSupplier
in interface Graph<V,E>
null
if the graph has no such supplierpublic void setEdgeSupplier(Supplier<E> edgeSupplier)
A graph uses the edge supplier to create new edge objects whenever a user calls method
Graph.addEdge(Object, Object)
. Users can also create the edge in user code and then
use method Graph.addEdge(Object, Object, Object)
to add the edge.
In contrast with the Supplier
interface, the edge supplier has the additional
requirement that a new and distinct result is returned every time it is invoked. More
specifically for a new edge to be added in a graph e
must not be equal to
any other edge in the graph (even if the graph allows edgemultiplicity). More formally, the
graph must not contain any edge e2
such that e2.equals(e)
.
edgeSupplier
 the edge supplierpublic Supplier<V> getVertexSupplier()
Graph
A graph uses the vertex supplier to create new vertex objects whenever a user calls method
Graph.addVertex()
. Users can also create the vertex in user code and then use method
Graph.addVertex(Object)
to add the vertex.
In contrast with the Supplier
interface, the vertex supplier has the additional
requirement that a new and distinct result is returned every time it is invoked. More
specifically for a new vertex to be added in a graph v
must not be equal
to any other vertex in the graph. More formally, the graph must not contain any vertex
v2
such that v2.equals(v)
.
Care must also be taken when interchanging calls to methods Graph.addVertex(Object)
and Graph.addVertex()
. In such a case the user must make sure never to add vertices
in the graph using method Graph.addVertex(Object)
, which are going to be returned in
the future by the supplied vertex supplier. Such a sequence will result into an
IllegalArgumentException
when calling method Graph.addVertex()
.
getVertexSupplier
in interface Graph<V,E>
null
if the graph has no such supplierpublic void setVertexSupplier(Supplier<V> vertexSupplier)
A graph uses the vertex supplier to create new vertex objects whenever a user calls method
Graph.addVertex()
. Users can also create the vertex in user code and then use method
Graph.addVertex(Object)
to add the vertex.
In contrast with the Supplier
interface, the vertex supplier has the additional
requirement that a new and distinct result is returned every time it is invoked. More
specifically for a new vertex to be added in a graph v
must not be equal
to any other vertex in the graph. More formally, the graph must not contain any vertex
v2
such that v2.equals(v)
.
Care must also be taken when interchanging calls to methods Graph.addVertex(Object)
and Graph.addVertex()
. In such a case the user must make sure never to add vertices
in the graph using method Graph.addVertex(Object)
, which are going to be returned in
the future by the supplied vertex supplier. Such a sequence will result into an
IllegalArgumentException
when calling method Graph.addVertex()
.
vertexSupplier
 the vertex supplierpublic E getEdge(V sourceVertex, V targetVertex)
null
. If any of the specified vertices is null
returns null
In undirected graphs, the returned edge may have its source and target vertices in the opposite order.
public E addEdge(V sourceVertex, V targetVertex)
null
.
The source and target vertices must already be contained in this graph. If they are not found
in graph IllegalArgumentException
is thrown.
This method creates the new edge e
using this graph's edge supplier (see
Graph.getEdgeSupplier()
). For the new edge to be added e
must not be
equal to any other edge the graph (even if the graph allows edgemultiplicity). More
formally, the graph must not contain any edge e2
such that
e2.equals(e)
. If such
e2
is found then the newly created edge e
is abandoned, the method leaves
this graph unchanged and returns null
.
If the underlying graph implementation's Graph.getEdgeSupplier()
returns
null
, then this method cannot create edges and throws an
UnsupportedOperationException
.
addEdge
in interface Graph<V,E>
sourceVertex
 source vertex of the edge.targetVertex
 target vertex of the edge.
null
.Graph.getEdgeSupplier()
public boolean addEdge(V sourceVertex, V targetVertex, E e)
e
, to this graph if this graph contains no edge e2
such that
e2.equals(e)
. If this graph already contains such an edge, the call leaves this
graph unchanged and returns false. Some graphs do not allow edgemultiplicity. In
such cases, if the graph already contains an edge from the specified source to the specified
target, than this method does not change the graph and returns
false
. If the edge was added to the graph, returns
true
.
The source and target vertices must already be contained in this graph. If they are not found in graph IllegalArgumentException is thrown.
addEdge
in interface Graph<V,E>
sourceVertex
 source vertex of the edge.targetVertex
 target vertex of the edge.e
 edge to be added to this graph.Graph.addEdge(Object, Object)
,
Graph.getEdgeSupplier()
public V addVertex()
Graph
This method creates the new vertex v
using this graph's vertex supplier (see
Graph.getVertexSupplier()
). For the new vertex to be added v
must not
be equal to any other vertex in the graph. More formally, the graph must not contain any
vertex v2
such that v2.equals(v)
. If such
v2
is found then the newly created vertex v
is abandoned, the method
leaves this graph unchanged and throws an IllegalArgumentException
.
If the underlying graph implementation's Graph.getVertexSupplier()
returns
null
, then this method cannot create vertices and throws an
UnsupportedOperationException
.
Care must also be taken when interchanging calls to methods Graph.addVertex(Object)
and Graph.addVertex()
. In such a case the user must make sure never to add vertices
in the graph using method Graph.addVertex(Object)
, which are going to be returned in
the future by the supplied vertex supplier. Such a sequence will result into an
IllegalArgumentException
when calling method Graph.addVertex()
.
addVertex
in interface Graph<V,E>
Graph.getVertexSupplier()
public boolean addVertex(V v)
v
, to this graph if this graph contains no vertex
u
such that
u.equals(v)
. If this graph already contains such vertex, the call leaves this graph
unchanged and returns false. In combination with the restriction on constructors,
this ensures that graphs never contain duplicate vertices.public V getEdgeSource(E e)
getEdgeSource
in interface Graph<V,E>
e
 edge of interestpublic V getEdgeTarget(E e)
getEdgeTarget
in interface Graph<V,E>
e
 edge of interestpublic Object clone()
clone
in class Object
RuntimeException
 in case the clone is not supportedObject.clone()
public boolean containsEdge(E e)
e2
such that
e.equals(e2)
. If the specified edge is null
returns
false
.containsEdge
in interface Graph<V,E>
e
 edge whose presence in this graph is to be tested.public boolean containsVertex(V v)
u
such that
u.equals(v)
. If the specified vertex is null
returns
false
.containsVertex
in interface Graph<V,E>
v
 vertex whose presence in this graph is to be tested.public int degreeOf(V vertex)
A degree of a vertex in an undirected graph is the number of edges touching that vertex. Edges with same source and target vertices (selfloops) are counted twice.
In directed graphs this method returns the sum of the "in degree" and the "out degree".
public Set<E> edgeSet()
The graph implementation may maintain a particular set ordering (e.g. via
LinkedHashSet
) for deterministic iteration, but this is not required. It is
the responsibility of callers who rely on this behavior to only use graph implementations
which support it.
public Set<E> edgesOf(V vertex)
public int inDegreeOf(V vertex)
The "in degree" of a vertex in a directed graph is the number of inward directed edges from that vertex. See http://mathworld.wolfram.com/Indegree.html.
In the case of undirected graphs this method returns the number of edges touching the vertex. Edges with same source and target vertices (selfloops) are counted twice.
inDegreeOf
in interface Graph<V,E>
vertex
 vertex whose degree is to be calculated.public Set<E> incomingEdgesOf(V vertex)
In the case of undirected graphs this method returns all edges touching the vertex, thus, some of the returned edges may have their source and target vertices in the opposite order.
incomingEdgesOf
in interface Graph<V,E>
vertex
 the vertex for which the list of incoming edges to be returned.public int outDegreeOf(V vertex)
The "out degree" of a vertex in a directed graph is the number of outward directed edges from that vertex. See http://mathworld.wolfram.com/Outdegree.html.
In the case of undirected graphs this method returns the number of edges touching the vertex. Edges with same source and target vertices (selfloops) are counted twice.
outDegreeOf
in interface Graph<V,E>
vertex
 vertex whose degree is to be calculated.public Set<E> outgoingEdgesOf(V vertex)
In the case of undirected graphs this method returns all edges touching the vertex, thus, some of the returned edges may have their source and target vertices in the opposite order.
outgoingEdgesOf
in interface Graph<V,E>
vertex
 the vertex for which the list of outgoing edges to be returned.public E removeEdge(V sourceVertex, V targetVertex)
null
otherwise.removeEdge
in interface Graph<V,E>
sourceVertex
 source vertex of the edge.targetVertex
 target vertex of the edge.null
if no edge removed.public boolean removeEdge(E e)
e2
such that e2.equals(e)
, if the graph contains such edge. Returns
true if the graph contained the specified edge. (The graph will not contain the
specified edge once the call returns).
If the specified edge is null
returns
false
.
removeEdge
in interface Graph<V,E>
e
 edge to be removed from this graph, if present.true
if and only if the graph contained the specified edge.public boolean removeVertex(V v)
u
such that u.equals(v)
, the call removes all edges that touch
u
and then removes u
itself. If no such u
is found,
the call leaves the graph unchanged. Returns true if the graph contained the
specified vertex. (The graph will not contain the specified vertex once the call returns).
If the specified vertex is null
returns
false
.
removeVertex
in interface Graph<V,E>
v
 vertex to be removed from this graph, if present.true
if the graph contained the specified vertex; false
otherwise.public Set<V> vertexSet()
The graph implementation may maintain a particular set ordering (e.g. via
LinkedHashSet
) for deterministic iteration, but this is not required. It is
the responsibility of callers who rely on this behavior to only use graph implementations
which support it.
public double getEdgeWeight(E e)
Graph.DEFAULT_EDGE_WEIGHT
), allowing weightedgraph algorithms to apply to them when
meaningful.getEdgeWeight
in interface Graph<V,E>
e
 edge of interestpublic void setEdgeWeight(E e, double weight)
setEdgeWeight
in interface Graph<V,E>
e
 the edgeweight
 the weightUnsupportedOperationException
 if the graph is not weightedpublic GraphType getType()
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