com.vividsolutions.jts.planargraph
Class PlanarGraph

java.lang.Object
  com.vividsolutions.jts.planargraph.PlanarGraph

Direct Known Subclasses:

LineMergeGraph

public abstract class PlanarGraph
extends java.lang.Object

Represents a directed graph which is embeddable in a planar surface.

This class and the other classes in this package serve as a framework for building planar graphs for specific algorithms. This class must be subclassed to expose appropriate methods to construct the graph. This allows controlling the types of graph components (DirectedEdges, Edges and Nodes) which can be added to the graph. An application which uses the graph framework will almost always provide subclasses for one or more graph components, which hold application-specific data and graph algorithms.

Version:

1.7

Field Summary

protected java.util.Set	dirEdges
protected java.util.Set	edges
protected NodeMap	nodeMap

Constructor Summary

PlanarGraph()
Constructs a empty graph.

Method Summary

protected void	add(DirectedEdge dirEdge) Adds the Edge to this PlanarGraph; only subclasses can add DirectedEdges, to ensure the edges added are of the right class.
protected void	add(Edge edge) Adds the Edge and its DirectedEdges with this PlanarGraph.
protected void	add(Node node) Adds a node to the map, replacing any that is already at that location.
boolean	contains(DirectedEdge de) Tests whether this graph contains the given DirectedEdge
boolean	contains(Edge e) Tests whether this graph contains the given Edge
java.util.Iterator	dirEdgeIterator() Returns an Iterator over the DirectedEdges in this PlanarGraph, in the order in which they were added.
java.util.Iterator	edgeIterator() Returns an Iterator over the Edges in this PlanarGraph, in the order in which they were added.
Node	findNode(Coordinate pt) Returns the Node at the given location, or null if no Node was there.
java.util.List	findNodesOfDegree(int degree) Returns all Nodes with the given number of Edges around it.
java.util.Collection	getEdges() Returns the Edges that have been added to this PlanarGraph
java.util.Collection	getNodes()
java.util.Iterator	nodeIterator() Returns an Iterator over the Nodes in this PlanarGraph.
void	remove(DirectedEdge de) Removes a DirectedEdge from its from-Node and from this graph.
void	remove(Edge edge) Removes an Edge and its associated DirectedEdges from their from-Nodes and from the graph.
void	remove(Node node) Removes a node from the graph, along with any associated DirectedEdges and Edges.

Methods inherited from class java.lang.Object

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

Field Detail

edges

protected java.util.Set edges

dirEdges

protected java.util.Set dirEdges

nodeMap

protected NodeMap nodeMap

Constructor Detail

PlanarGraph

public PlanarGraph()

Constructs a empty graph.

Method Detail

findNode

public Node findNode(Coordinate pt)

Returns the Node at the given location, or null if no Node was there.

Parameters:

pt - the location to query

Returns:

the node found

add

protected void add(Node node)

Adds a node to the map, replacing any that is already at that location. Only subclasses can add Nodes, to ensure Nodes are of the right type.

Parameters:

node - the node to add

add

protected void add(Edge edge)

Adds the Edge and its DirectedEdges with this PlanarGraph. Assumes that the Edge has already been created with its associated DirectEdges. Only subclasses can add Edges, to ensure the edges added are of the right class.

add

protected void add(DirectedEdge dirEdge)

Adds the Edge to this PlanarGraph; only subclasses can add DirectedEdges, to ensure the edges added are of the right class.

nodeIterator

public java.util.Iterator nodeIterator()

Returns an Iterator over the Nodes in this PlanarGraph.

contains

public boolean contains(Edge e)

Tests whether this graph contains the given Edge

Parameters:

e - the edge to query

Returns:

true if the graph contains the edge

contains

public boolean contains(DirectedEdge de)

Tests whether this graph contains the given DirectedEdge

Parameters:

de - the directed edge to query

Returns:

true if the graph contains the directed edge

getNodes

public java.util.Collection getNodes()

dirEdgeIterator

public java.util.Iterator dirEdgeIterator()

Returns an Iterator over the DirectedEdges in this PlanarGraph, in the order in which they were added.

See Also:

add(Edge), add(DirectedEdge)

edgeIterator

public java.util.Iterator edgeIterator()

Returns an Iterator over the Edges in this PlanarGraph, in the order in which they were added.

See Also:

add(Edge)

getEdges

public java.util.Collection getEdges()

Returns the Edges that have been added to this PlanarGraph

See Also:

add(Edge)

remove

public void remove(Edge edge)

Removes an Edge and its associated DirectedEdges from their from-Nodes and from the graph. Note: This method does not remove the Nodes associated with the Edge, even if the removal of the Edge reduces the degree of a Node to zero.

remove

public void remove(DirectedEdge de)

Removes a DirectedEdge from its from-Node and from this graph. This method does not remove the Nodes associated with the DirectedEdge, even if the removal of the DirectedEdge reduces the degree of a Node to zero.

remove

public void remove(Node node)

Removes a node from the graph, along with any associated DirectedEdges and Edges.

findNodesOfDegree

public java.util.List findNodesOfDegree(int degree)

Returns all Nodes with the given number of Edges around it.