org.geotools.graph.build.line

Class OptLineGraphGenerator

Object

OptLineGraphGenerator

All Implemented Interfaces:

GraphGenerator, LineGraphGenerator

Direct Known Subclasses:

OptDirectedLineGraphGenerator

public class OptLineGraphGenerator
extends Object
implements LineGraphGenerator

An implementation of GraphGenerator used to generate an optimized graph representing a line network. Graphs are generated by supplying the generator with objects of type LineSegment via the add(Object) method.

For each line segment added, an edge in the graph is created. The builder records the end coordinates of each line added, and maintains a map of coordinates to nodes, creating nodes when neccessary.

Edges created by the generator are of type OptBasicEdge.
Nodes created by the generator are of type OptXYNode.

Since building optimized graphs requires knowing the degree of nodes before creating them, the physical construction of the graph is delayed until a call to generate() is made. No component is created with a call to add(Object), only information about the object is recorded.

Author:

Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net

See Also:

OptEdge, OptXYNode

Constructor Summary

Constructors

Constructor and Description
OptLineGraphGenerator() Constructs a new OptLineGraphGenerator.

Method Summary

Modifier and Type	Method and Description
Graphable	add(Object obj) Adds a line to the graph.
void	generate() Performs the actual generation of the graph.
protected Edge	generateEdge(LineSegment line)
protected void	generateEdges()
protected void	generateNodes()
Graphable	get(Object obj) Returns the edge which represents a line.
Edge	getEdge(Coordinate c1, Coordinate c2) Retrieve edge between the two coordinates.
Graph	getGraph() Returns the graph being generated.
GraphBuilder	getGraphBuilder() Returns the underlying builder.
protected List	getLines() Returns the lines added to the graph.
Node	getNode(Coordinate c) Look up a Node for the provided coordinate.
Map	getNodeMap() Returns the coordinate to node map.
Graphable	remove(Object obj) Unsupported operation.
void	setGraphBuilder(GraphBuilder builder) Sets the underlying builder used to physically construct the graph.

Methods inherited from class Object

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

Constructor Detail

OptLineGraphGenerator

public OptLineGraphGenerator()

Constructs a new OptLineGraphGenerator.

Method Detail

add

public Graphable add(Object obj)

Adds a line to the graph. Note that this method returns null since actual building of the graph components is delayed until generate() is called.

Specified by:

add in interface GraphGenerator

Parameters:

obj - A LineSegment object.

Returns:

null because the actual building of the graph components is delayed until generate() is called.

get

public Graphable get(Object obj)

Returns the edge which represents a line. This method must be called after the call to generate(). Note that if the exact same line has been added to the graph multiple times, then only one of the edges that represents it will be returned. It is undefined which edge will be returned.

Specified by:

get in interface GraphGenerator

Parameters:

obj - An instance of LineSegment.

Returns:

Edge that represents the line.

See Also:

GraphGenerator.get(Object)

remove

public Graphable remove(Object obj)

Unsupported operation.

Specified by:

remove in interface GraphGenerator

Parameters:

obj - The object modelled by the component.

Returns:

The graph component used to model the object.

Throws:

UnsupportedOperationException

setGraphBuilder

public void setGraphBuilder(GraphBuilder builder)

Description copied from interface: GraphGenerator

Sets the underlying builder used to physically construct the graph.

Specified by:

setGraphBuilder in interface GraphGenerator

Parameters:

builder - The new underlying GraphBuilder.

See Also:

GraphGenerator.setGraphBuilder(GraphBuilder)

getGraphBuilder

public GraphBuilder getGraphBuilder()

Description copied from interface: GraphGenerator

Returns the underlying builder.

Specified by:

getGraphBuilder in interface GraphGenerator

Returns:

The underyling builder.

See Also:

GraphGenerator.getGraphBuilder()

getGraph

public Graph getGraph()

Description copied from interface: GraphGenerator

Returns the graph being generated.

Specified by:

getGraph in interface GraphGenerator

Returns:

The generated graph.

See Also:

GraphGenerator.getGraph()

generate

public void generate()

Performs the actual generation of the graph.

getNodeMap

public Map getNodeMap()

Returns the coordinate to node map. Note that before the call to generate the map does not contain any nodes.

Returns:

Coordinate to node map.

getLines

protected List getLines()

Returns the lines added to the graph.

Returns:

A list of LineSegment objects.

generateNodes

protected void generateNodes()

generateEdges

protected void generateEdges()

generateEdge

protected Edge generateEdge(LineSegment line)

getNode

public Node getNode(Coordinate c)

Description copied from interface: LineGraphGenerator

Look up a Node for the provided coordinate.

Specified by:

getNode in interface LineGraphGenerator

Returns:

Node

getEdge

public Edge getEdge(Coordinate c1,
                    Coordinate c2)

Description copied from interface: LineGraphGenerator

Retrieve edge between the two coordinates.

Specified by:

getEdge in interface LineGraphGenerator

Returns:

Edge