com.phoenixst.plexus
Interface Graph

All Known Subinterfaces:

ObservableGraph

All Known Implementing Classes:

AbstractGraph, AbstractIntegerNodeGraph, CirculantGraph, CompleteBipartiteGraph, CompleteGraph, CompleteTree, Cycle, DefaultGraph, DefaultOrientedForest, EmptyGraph, FileSystemForest, FilteredGraph, GraphTransformer, GraphWrapper, Join, LoggingGraph, LoopGraph, ObservableGraphWrapper, Path, PetersenGraph, PlanarMesh, Prism, Product, SingletonGraph, Star, SynchronizedGraph, ToroidalMesh, UnmodifiableGraph, Wheel

public interface Graph

The root interface of the graph hierarchy.

See the Overview Summary for details not included here.

Nodes must contain unique (using Object.equals()) user-provided objects. This requirement allows nodes to be referenced unambiguously (when creating edges, for example). The user-defined objects contained in Graph.Edge objects, however, are not subject to this requirement in the general case, although Object.equals() will be used for edge comparisons.

Nothing in this interface prohibits a Graph.Edge from also being a node in the same Graph. In other words, Graph.Edges can point to other Graph.Edges. If a particular Graph implementation allows this, these two aspects of any particular Graph.Edge are independent. Adding or removing an Graph.Edge as a node has no impact upon the object's existence as a Graph.Edge, and vice versa.

All general-purpose implementations of this interface should provide two "standard" constructors: a void (no arguments) constructor, which creates an empty graph, and a constructor with a single argument of type Graph, which creates a new graph with the same elements as its argument.

Since:

1.0

Version:

$Revision: 1.43 $

Author:

Ray A. Conner

Nested Class Summary

static interface

Graph.Edge An interface describing an edge in a Graph.

Method Summary

Graph.Edge	addEdge(Object object, Object tail, Object head, boolean isDirected) Adds the specified edge to the Graph (optional operation).
boolean	addNode(Object node) Adds node to this Graph (optional operation).
Collection	adjacentNodes(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns the nodes adjacent to the specified node for which the specified Predicate is satisfied.
boolean	containsEdge(Graph.Edge edge) Returns true if this Graph contains the specified Graph.Edge.
boolean	containsNode(Object node) Returns true if this Graph contains the specified node.
int	degree(Object node) Returns the degree of node, defined as the number of edges incident on node, with self-loops counted twice.
int	degree(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns the degree of node for which the specified Predicate is satisfied, defined as the number of edges incident on node that pass the predicate, with self-loops counted only once.
Collection	edges(org.apache.commons.collections.Predicate edgePredicate) Returns the Graph.Edges from this Graph that satisfy the specified predicate.
Object	getAdjacentNode(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns a node adjacent to the specified node for which the specified Predicate is satisfied.
Graph.Edge	getEdge(org.apache.commons.collections.Predicate edgePredicate) Returns a Graph.Edge from this Graph that satisfies the specified predicate, or null if no such Graph.Edge exists.
Graph.Edge	getIncidentEdge(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns a Graph.Edge incident on the specified node for which the specified Predicate is satisfied.
Object	getNode(org.apache.commons.collections.Predicate nodePredicate) Returns a node from this Graph that satisfies the specified predicate, or null if no such node exists.
Collection	incidentEdges(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns the Graph.Edges incident on the specified node for which the specified Predicate is satisfied.
Collection	nodes(org.apache.commons.collections.Predicate nodePredicate) Returns the nodes from this Graph that satisfy the specified predicate.
boolean	removeEdge(Graph.Edge edge) Removes the specified Graph.Edge from this Graph (optional operation).
boolean	removeNode(Object node) Removes node from this Graph (optional operation).
Traverser	traverser(Object node, org.apache.commons.collections.Predicate traverserPredicate) Returns a Traverser from node to all adjacent nodes for which the specified Predicate is satisfied.

Method Detail

addNode

boolean addNode(Object node)

Adds node to this Graph (optional operation). Returns true if this Graph changed as a result of the call. Returns false if this Graph already contains node.

If a Graph refuses to add a particular node for any reason other than that it already contains the node, it must throw an exception (rather than returning false). This preserves the invariant that a Graph always contains the specified node after this call returns. Graph classes should clearly specify in their documentation any other restrictions on what nodes may be added.

Parameters:

node - the node to be added to this Graph.

Returns:

true if this Graph changed as a result of the call, false if this Graph already contains the specified node.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

UnsupportedOperationException - if this method is not supported by this Graph.

removeNode

boolean removeNode(Object node)

Removes node from this Graph (optional operation). This method will also remove all edges incident on node.

Parameters:

node - the node to be removed from this Graph.

Returns:

true if this Graph contained node.

Throws:

UnsupportedOperationException - if this method is not supported by this Graph.

containsNode

boolean containsNode(Object node)

Returns true if this Graph contains the specified node.

Parameters:

node - the node whose presence in this Graph is to be tested.

Returns:

true if this Graph contains the specified node.

addEdge

Graph.Edge addEdge(Object object,
                   Object tail,
                   Object head,
                   boolean isDirected)

Adds the specified edge to the Graph (optional operation). Returns the newly created Graph.Edge if this Graph changed as a result of the call. Returns null if this Graph does not allow duplicate edges and already contains the specified edge.

If a Graph refuses to add a particular edge for any reason other than that it already contains the edge, it must throw an exception (rather than returning null). This preserves the invariant that a Graph always contains the specified edge after this call returns. Graph classes should clearly specify in their documentation any other restrictions on what edges may be added.

Parameters:

object - the user-defined object to be contained in the new edge.

tail - the first endpoint of the new edge.

head - the second endpoint of the new edge.

isDirected - whether the new edge is directed.

Returns:

the newly created Graph.Edge if this Graph changed as a result of the call, null if this Graph does not allow duplicate edges and already contains the specified edge.

Throws:

ClassCastException - if the class of object, tail, or head is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of object, tail, head, or isDirected is inappropriate for this Graph.

IllegalArgumentException - if object, tail, or head is null and this Graph does not not permit null edges and/or nodes.

NoSuchNodeException - if tail or head is not present in this Graph.

UnsupportedOperationException - if this method is not supported by this Graph.

removeEdge

boolean removeEdge(Graph.Edge edge)

Removes the specified Graph.Edge from this Graph (optional operation).

Parameters:

edge - the Graph.Edge to be removed from this Graph.

Returns:

true if this Graph contained the specified Graph.Edge.

Throws:

UnsupportedOperationException - if this method is not supported by this Graph.

containsEdge

boolean containsEdge(Graph.Edge edge)

Returns true if this Graph contains the specified Graph.Edge.

Parameters:

edge - the Graph.Edge whose presence in this Graph is to be tested.

Returns:

true if this Graph contains the specified Graph.Edge.

degree

int degree(Object node)

Returns the degree of node, defined as the number of edges incident on node, with self-loops counted twice. If this node has more than Integer.MAX_VALUE incident edges, returns Integer.MAX_VALUE.

Parameters:

node - return the degree of this node.

Returns:

the degree of node.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

degree

int degree(Object node,
           org.apache.commons.collections.Predicate traverserPredicate)

Returns the degree of node for which the specified Predicate is satisfied, defined as the number of edges incident on node that pass the predicate, with self-loops counted only once. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge. If this node has more than Integer.MAX_VALUE such edges, returns Integer.MAX_VALUE.

Parameters:

node - return the degree of this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the counted Graph.Edges must satisfy.

Returns:

the degree of node for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

nodes

Collection nodes(org.apache.commons.collections.Predicate nodePredicate)

Returns the nodes from this Graph that satisfy the specified predicate.

Parameters:

nodePredicate - the predicate which the returned nodes must satisfy.

Returns:

the nodes from this Graph that satisfy the specified predicate.

edges

Collection edges(org.apache.commons.collections.Predicate edgePredicate)

Returns the Graph.Edges from this Graph that satisfy the specified predicate.

Parameters:

edgePredicate - the predicate which the returned Graph.Edges must satisfy.

Returns:

the Graph.Edges from this Graph that satisfy the specified predicate.

adjacentNodes

Collection adjacentNodes(Object node,
                         org.apache.commons.collections.Predicate traverserPredicate)

Returns the nodes adjacent to the specified node for which the specified Predicate is satisfied. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge. It should be noted that removing a node from the returned Collection merely removes one instance of it being adjacent to the specified node. In other words, a connecting Graph.Edge is removed.

Parameters:

node - return the nodes adjacent to this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the returned nodes and the traversed Graph.Edges must satisfy.

Returns:

the nodes adjacent to the specified node for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

incidentEdges

Collection incidentEdges(Object node,
                         org.apache.commons.collections.Predicate traverserPredicate)

Returns the Graph.Edges incident on the specified node for which the specified Predicate is satisfied. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge.

Parameters:

node - return the Graph.Edges incident on this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the returned Graph.Edges must satisfy.

Returns:

the Graph.Edges incident on the specified node for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

getNode

Object getNode(org.apache.commons.collections.Predicate nodePredicate)

Returns a node from this Graph that satisfies the specified predicate, or null if no such node exists.

Parameters:

nodePredicate - the predicate which the returned node must satisfy.

Returns:

a node from this Graph that satisfies the specified predicate, or null if no such node exists.

getEdge

Graph.Edge getEdge(org.apache.commons.collections.Predicate edgePredicate)

Returns a Graph.Edge from this Graph that satisfies the specified predicate, or null if no such Graph.Edge exists.

Parameters:

edgePredicate - the predicate which the returned Graph.Edge must satisfy.

Returns:

a Graph.Edge from this Graph that satisfies the specified predicate, or null if no such Graph.Edge exists.

getAdjacentNode

Object getAdjacentNode(Object node,
                       org.apache.commons.collections.Predicate traverserPredicate)

Returns a node adjacent to the specified node for which the specified Predicate is satisfied. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge.

Parameters:

node - traverse to a node adjacent to this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the returned node and the traversed Graph.Edge must satisfy.

Returns:

a node adjacent to the specified node for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

getIncidentEdge

Graph.Edge getIncidentEdge(Object node,
                           org.apache.commons.collections.Predicate traverserPredicate)

Returns a Graph.Edge incident on the specified node for which the specified Predicate is satisfied. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge.

Parameters:

node - traverse to a Graph.Edge incident on this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the returned Graph.Edge must satisfy.

Returns:

a Graph.Edge incident on the specified node for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.

traverser

Traverser traverser(Object node,
                    org.apache.commons.collections.Predicate traverserPredicate)

Returns a Traverser from node to all adjacent nodes for which the specified Predicate is satisfied. The argument to the Predicate.evaluate() method is expected to be an OrderedPair. The first element of the OrderedPair is the specified node, the second is the Graph.Edge. The nodes returned by Iterator.next() are not necessarily distinct. Self-loops are only traversed once. There are no guarantees concerning the order in which the nodes are returned (unless this Graph is an instance of some class that provides a guarantee).

Parameters:

node - traverse over all nodes adjacent to this node for which the specified predicate is satisfied.

traverserPredicate - the predicate which the returned nodes and their traversed Graph.Edges must satisfy.

Returns:

a Traverser from node to all adjacent nodes for which the specified predicate is satisfied.

Throws:

ClassCastException - if the class of node is of an inappropriate class for this Graph.

IllegalArgumentException - if some aspect of node is inappropriate for this Graph.

IllegalArgumentException - if node is null and this Graph does not not permit null nodes.

NoSuchNodeException - if node is not present in this Graph.