Top Description Methods
com.google.common.graph

public Interface ValueGraph<N, V>

extends BaseGraph<N>
Known Direct Subinterfaces
com.google.common.graph.MutableValueGraph
Known Direct Implementers
com.google.common.graph.AbstractValueGraph
Annotations
@Beta
@ElementTypesAreNonnullByDefault
Type Parameters
<N>
Node parameter type
<V>
Value parameter type
Imports
com.google.common.annotations.Beta, java.util.Optional, .Set, javax.annotation.CheckForNull

An interface for graph-structured data, whose edges have associated non-unique values.

A graph is composed of a set of nodes and a set of edges connecting pairs of nodes.

There are three primary interfaces provided to represent graphs. In order of increasing complexity they are: Graph, ValueGraph, and Network. You should generally prefer the simplest interface that satisfies your use case. See the "Choosing the right graph type" section of the Guava User Guide for more details.

Capabilities

ValueGraph supports the following use cases (definitions of terms):

ValueGraph, as a subtype of Graph, explicitly does not support parallel edges, and forbids implementations or extensions with parallel edges. If you need parallel edges, use Network. (You can use a positive Integer edge value as a loose representation of edge multiplicity, but the *degree() and mutation methods will not reflect your interpretation of the edge value as its multiplicity.)

Building a ValueGraph

The implementation classes that common.graph provides are not public, by design. To create an instance of one of the built-in implementations of ValueGraph, use the ValueGraphBuilder class:

MutableValueGraph<Integer, Double> graph = ValueGraphBuilder.directed().build();

ValueGraphBuilder#build() returns an instance of MutableValueGraph, which is a subtype of ValueGraph that provides methods for adding and removing nodes and edges. If you do not need to mutate a graph (e.g. if you write a method than runs a read-only algorithm on the graph), you should use the non-mutating ValueGraph interface, or an ImmutableValueGraph.

You can create an immutable copy of an existing ValueGraph using ImmutableValueGraph#copyOf(ValueGraph):

ImmutableValueGraph<Integer, Double> immutableGraph = ImmutableValueGraph.copyOf(graph);

Instances of ImmutableValueGraph do not implement MutableValueGraph (obviously!) and are contractually guaranteed to be unmodifiable and thread-safe.

The Guava User Guide has more information on (and examples of) building graphs.

Additional documentation

See the Guava User Guide for the common.graph package ("Graphs Explained") for additional documentation, including:

Authors
James Sexton, Joshua O'Madadhain
Since
20.0

Method Summary

Modifier and TypeMethod and Description
public Set<N>
adjacentNodes(N node)

Redeclares com.google.common.graph.BaseGraph.adjacentNodes.

Returns a live view of the nodes which have an incident edge in common with node in this graph.
public boolean
allowsSelfLoops()

Redeclares com.google.common.graph.BaseGraph.allowsSelfLoops.

Returns true if this graph allows self-loops (edges that connect a node to itself).
public Graph<N>
asGraph()

Returns a live view of this graph as a Graph.

public int
degree(N node)

Redeclares com.google.common.graph.BaseGraph.degree.

Returns the count of node's incident edges, counting self-loops twice (equivalently, the number of times an edge touches node).
public Set<EndpointPair<N>>
edges()

Redeclares com.google.common.graph.BaseGraph.edges.

Returns all edges in this graph.
public Optional<V>
edgeValue(N nodeU, N nodeV)

Returns the value of the edge that connects nodeU to nodeV (in the order, if any, specified by endpoints), if one is present; otherwise, returns Optional.empty().

public Optional<V>
edgeValue(EndpointPair<N> endpoints)

Returns the value of the edge that connects endpoints (in the order, if any, specified by endpoints), if one is present; otherwise, returns Optional.empty().

public V
edgeValueOrDefault(N nodeU, N nodeV, V defaultValue)

Returns the value of the edge that connects nodeU to nodeV, if one is present; otherwise, returns defaultValue.

public V
edgeValueOrDefault(EndpointPair<N> endpoints, V defaultValue)

Returns the value of the edge that connects endpoints (in the order, if any, specified by endpoints), if one is present; otherwise, returns defaultValue.

public boolean
equals(Object object)

Returns true iff object is a ValueGraph that has the same elements and the same structural relationships as those in this graph.

public boolean
hasEdgeConnecting(N nodeU, N nodeV)

Redeclares com.google.common.graph.BaseGraph.hasEdgeConnecting.

Returns true if there is an edge that directly connects nodeU to nodeV.
public boolean
hasEdgeConnecting(EndpointPair<N> endpoints)

Redeclares com.google.common.graph.BaseGraph.hasEdgeConnecting.

Returns true if there is an edge that directly connects endpoints (in the order, if any, specified by endpoints).
public int
hashCode()

Returns the hash code for this graph.

public ElementOrder<N>
public Set<EndpointPair<N>>
incidentEdges(N node)

Redeclares com.google.common.graph.BaseGraph.incidentEdges.

Returns a live view of the edges in this graph whose endpoints include node.
public int
inDegree(N node)

Redeclares com.google.common.graph.BaseGraph.inDegree.

Returns the count of node's incoming edges (equal to predecessors(node).size()) in a directed graph.
public boolean
isDirected()

Redeclares com.google.common.graph.BaseGraph.isDirected.

Returns true if the edges in this graph are directed.
public ElementOrder<N>
nodeOrder()

Redeclares com.google.common.graph.BaseGraph.nodeOrder.

Returns the order of iteration for the elements of nodes().
public Set<N>
nodes()

Redeclares com.google.common.graph.BaseGraph.nodes.

Returns all nodes in this graph, in the order specified by nodeOrder().
public int
outDegree(N node)

Redeclares com.google.common.graph.BaseGraph.outDegree.

Returns the count of node's outgoing edges (equal to successors(node).size()) in a directed graph.
public Set<N>
predecessors(N node)

Redeclares com.google.common.graph.BaseGraph.predecessors.

Returns a live view of all nodes in this graph adjacent to node which can be reached by traversing node's incoming edges against the direction (if any) of the edge.
public Set<N>
successors(N node)

Redeclares com.google.common.graph.BaseGraph.successors.

Returns a live view of all nodes in this graph adjacent to node which can be reached by traversing node's outgoing edges in the direction (if any) of the edge.

Method Detail

adjacentNodesback to summary
public Set<N> adjacentNodes(N node)

Redeclares com.google.common.graph.BaseGraph.adjacentNodes.

Returns a live view of the nodes which have an incident edge in common with node in this graph.

This is equal to the union of predecessors(Object) and successors(Object).

If node is removed from the graph after this method is called, the Set view returned by this method will be invalidated, and will throw IllegalStateException if it is accessed in any way, with the following exceptions:

  • view.equals(view) evaluates to true (but any other `equals()` expression involving view will throw)
  • hashCode() does not throw
  • if node is re-added to the graph after having been removed, view's behavior is undefined
Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
allowsSelfLoopsback to summary
public boolean allowsSelfLoops()

Redeclares com.google.common.graph.BaseGraph.allowsSelfLoops.

Returns true if this graph allows self-loops (edges that connect a node to itself). Attempting to add a self-loop to a graph that does not allow them will throw an IllegalArgumentException.

Annotations
@Override
asGraphback to summary
public Graph<N> asGraph()

Returns a live view of this graph as a Graph. The resulting Graph will have an edge connecting node A to node B if this ValueGraph has an edge connecting A to B.

degreeback to summary
public int degree(N node)

Redeclares com.google.common.graph.BaseGraph.degree.

Returns the count of node's incident edges, counting self-loops twice (equivalently, the number of times an edge touches node).

For directed graphs, this is equal to inDegree(node) + outDegree(node).

For undirected graphs, this is equal to incidentEdges(node).size() + (number of self-loops incident to node).

If the count is greater than Integer.MAX_VALUE, returns Integer.MAX_VALUE.

Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
edgesback to summary
public Set<EndpointPair<N>> edges()

Redeclares com.google.common.graph.BaseGraph.edges.

Returns all edges in this graph.

Annotations
@Override
edgeValueback to summary
public Optional<V> edgeValue(N nodeU, N nodeV)

Returns the value of the edge that connects nodeU to nodeV (in the order, if any, specified by endpoints), if one is present; otherwise, returns Optional.empty().

Exceptions
IllegalArgumentException:
if nodeU or nodeV is not an element of this graph
Since
23.0 (since 20.0 with return type V)
edgeValueback to summary
public Optional<V> edgeValue(EndpointPair<N> endpoints)

Returns the value of the edge that connects endpoints (in the order, if any, specified by endpoints), if one is present; otherwise, returns Optional.empty().

If this graph is directed, the endpoints must be ordered.

Exceptions
IllegalArgumentException:
  • if either endpoint is not an element of this graph
  • if the endpoints are unordered and the graph is directed
Since
27.1
edgeValueOrDefaultback to summary
public V edgeValueOrDefault(N nodeU, N nodeV, V defaultValue)

Returns the value of the edge that connects nodeU to nodeV, if one is present; otherwise, returns defaultValue.

In an undirected graph, this is equal to edgeValueOrDefault(nodeV, nodeU, defaultValue).

Annotations
@CheckForNull
Exceptions
IllegalArgumentException:
if nodeU or nodeV is not an element of this graph
edgeValueOrDefaultback to summary
public V edgeValueOrDefault(EndpointPair<N> endpoints, V defaultValue)

Returns the value of the edge that connects endpoints (in the order, if any, specified by endpoints), if one is present; otherwise, returns defaultValue.

If this graph is directed, the endpoints must be ordered.

Annotations
@CheckForNull
Exceptions
IllegalArgumentException:
  • if either endpoint is not an element of this graph
  • if the endpoints are unordered and the graph is directed
Since
27.1
equalsback to summary
public boolean equals(Object object)

Returns true iff object is a ValueGraph that has the same elements and the same structural relationships as those in this graph.

Thus, two value graphs A and B are equal if all of the following are true:

Graph properties besides directedness do not affect equality. For example, two graphs may be considered equal even if one allows self-loops and the other doesn't. Additionally, the order in which nodes or edges are added to the graph, and the order in which they are iterated over, are irrelevant.

A reference implementation of this is provided by AbstractValueGraph#equals(Object).

Annotations
@Override
hasEdgeConnectingback to summary
public boolean hasEdgeConnecting(N nodeU, N nodeV)

Redeclares com.google.common.graph.BaseGraph.hasEdgeConnecting.

Returns true if there is an edge that directly connects nodeU to nodeV. This is equivalent to nodes().contains(nodeU) && successors(nodeU).contains(nodeV).

In an undirected graph, this is equal to hasEdgeConnecting(nodeV, nodeU).

Annotations
@Override
Since
23.0
hasEdgeConnectingback to summary
public boolean hasEdgeConnecting(EndpointPair<N> endpoints)

Redeclares com.google.common.graph.BaseGraph.hasEdgeConnecting.

Returns true if there is an edge that directly connects endpoints (in the order, if any, specified by endpoints). This is equivalent to edges().contains(endpoints).

Unlike the other EndpointPair-accepting methods, this method does not throw if the endpoints are unordered and the graph is directed; it simply returns false. This is for consistency with the behavior of Collection#contains(Object) (which does not generally throw if the object cannot be present in the collection), and the desire to have this method's behavior be compatible with edges().contains(endpoints).

Annotations
@Override
Since
27.1
hashCodeback to summary
public int hashCode()

Returns the hash code for this graph. The hash code of a graph is defined as the hash code of a map from each of its edges to the associated edge value.

A reference implementation of this is provided by AbstractValueGraph#hashCode().

Annotations
@Override
incidentEdgeOrderback to summary
public ElementOrder<N> incidentEdgeOrder()

Redeclares com.google.common.graph.BaseGraph.incidentEdgeOrder.

Returns an ElementOrder that specifies the order of iteration for the elements of edges(), adjacentNodes(Object), predecessors(Object), successors(Object) and incidentEdges(Object).

Annotations
@Override
Since
29.0
incidentEdgesback to summary
public Set<EndpointPair<N>> incidentEdges(N node)

Redeclares com.google.common.graph.BaseGraph.incidentEdges.

Returns a live view of the edges in this graph whose endpoints include node.

This is equal to the union of incoming and outgoing edges.

If node is removed from the graph after this method is called, the Set view returned by this method will be invalidated, and will throw IllegalStateException if it is accessed in any way, with the following exceptions:

  • view.equals(view) evaluates to true (but any other `equals()` expression involving view will throw)
  • hashCode() does not throw
  • if node is re-added to the graph after having been removed, view's behavior is undefined
Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
Since
24.0
inDegreeback to summary
public int inDegree(N node)

Redeclares com.google.common.graph.BaseGraph.inDegree.

Returns the count of node's incoming edges (equal to predecessors(node).size()) in a directed graph. In an undirected graph, returns the degree(Object).

If the count is greater than Integer.MAX_VALUE, returns Integer.MAX_VALUE.

Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
isDirectedback to summary
public boolean isDirected()

Redeclares com.google.common.graph.BaseGraph.isDirected.

Returns true if the edges in this graph are directed. Directed edges connect a source node to a target node, while undirected edges connect a pair of nodes to each other.

Annotations
@Override
nodeOrderback to summary
public ElementOrder<N> nodeOrder()

Redeclares com.google.common.graph.BaseGraph.nodeOrder.

Returns the order of iteration for the elements of nodes().

Annotations
@Override
nodesback to summary
public Set<N> nodes()

Redeclares com.google.common.graph.BaseGraph.nodes.

Returns all nodes in this graph, in the order specified by nodeOrder().

Annotations
@Override
outDegreeback to summary
public int outDegree(N node)

Redeclares com.google.common.graph.BaseGraph.outDegree.

Returns the count of node's outgoing edges (equal to successors(node).size()) in a directed graph. In an undirected graph, returns the degree(Object).

If the count is greater than Integer.MAX_VALUE, returns Integer.MAX_VALUE.

Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
predecessorsback to summary
public Set<N> predecessors(N node)

Redeclares com.google.common.graph.BaseGraph.predecessors.

Returns a live view of all nodes in this graph adjacent to node which can be reached by traversing node's incoming edges against the direction (if any) of the edge.

In an undirected graph, this is equivalent to adjacentNodes(Object).

If node is removed from the graph after this method is called, the `Set` returned by this method will be invalidated, and will throw `IllegalStateException` if it is accessed in any way.

Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph
successorsback to summary
public Set<N> successors(N node)

Redeclares com.google.common.graph.BaseGraph.successors.

Returns a live view of all nodes in this graph adjacent to node which can be reached by traversing node's outgoing edges in the direction (if any) of the edge.

In an undirected graph, this is equivalent to adjacentNodes(Object).

This is not the same as "all nodes reachable from node by following outgoing edges". For that functionality, see Graphs#reachableNodes(Graph, Object).

If node is removed from the graph after this method is called, the Set view returned by this method will be invalidated, and will throw IllegalStateException if it is accessed in any way, with the following exceptions:

  • view.equals(view) evaluates to true (but any other `equals()` expression involving view will throw)
  • hashCode() does not throw
  • if node is re-added to the graph after having been removed, view's behavior is undefined
Annotations
@Override
Exceptions
IllegalArgumentException:
if node is not an element of this graph