Package org.geotools.graph.build.line

Class BasicLineGraphGenerator

Object

BasicLineGraphGenerator

All Implemented Interfaces:

GraphGenerator, LineGraphGenerator

Direct Known Subclasses:

BasicDirectedLineGraphGenerator, LineStringGraphGenerator

public class BasicLineGraphGenerator
extends Object
implements LineGraphGenerator

An implementation of GraphGenerator used to generate a 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.

If a tolerance distance is set, the end coordinates matched to nodes with a tolerance distance (using a spatial index).

Edges created by the generator are of type BasicEdge and contain an object of type LineSegment.
Nodes created by the generator are of type BasicXYNode and contain an object of type Coordinate.

Author:

Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net, Anders Bakkevold, Bouvet AS, bakkedev@gmail.com

See Also:

• BasicXYNode
• BasicEdge
• LineSegment
• Coordinate

Constructor Summary

Constructors

Constructor	Description
BasicLineGraphGenerator()	Constructs a new BasicLineGraphGenerator.
BasicLineGraphGenerator(double tolerance)	Constructs a new BasicLineGraphGenerator.

Method Summary

Modifier and Type	Method	Description
Graphable	add(Object obj)	Adds a line to the graph.
protected LineSegment	alterLine(LineSegment line, Node n1, Node n2)
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.
Node	getNode(Coordinate c)	Look up a Node for the provided coordinate.
Map	getNodeMap()	Returns the coordinate to node map used to build nodes representing line endpoint coordinates.
Graphable	remove(Object obj)	Removes the edge from the graph that represents a line.
void	setGraphBuilder(GraphBuilder builder)	Sets the underlying builder used to physically construct the graph.
protected void	setObject(Edge e, Object obj)
protected void	setObject(Node n, Object obj)
protected boolean	useTolerance()

Methods inherited from class Object

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

Constructor Details

BasicLineGraphGenerator

public BasicLineGraphGenerator()

Constructs a new BasicLineGraphGenerator.

Tolerance is 0.0 as default, meaning coordinates must be equal for lines to connect at a node.

BasicLineGraphGenerator

public BasicLineGraphGenerator(double tolerance)

Constructs a new BasicLineGraphGenerator.

If two coordinates are considered equal (and should be snapped to the same Node), the distance between them must be less than the tolerance value.

Parameters:

tolerance - threshold distance value for coordinates to be considered equal

Method Details

add

public Graphable add(Object obj)

Adds a line to the graph.

Specified by:

add in interface GraphGenerator

Parameters:

obj - An instance of LineSegment.

Returns:

A BasicEdge.

See Also:

• LineSegment
• GraphGenerator.add(Object)

alterLine

protected LineSegment alterLine(LineSegment line,
 Node n1,
 Node n2)

get

public Graphable get(Object obj)

Returns the edge which represents a line. 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)

Removes the edge from the graph that represents a line.

Specified by:

remove in interface GraphGenerator

Parameters:

obj - The object modelled by the component.

Returns:

Edge that represents the line.

See Also:

• GraphGenerator.remove(Object)

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()

getNodeMap

public Map getNodeMap()

Returns the coordinate to node map used to build nodes representing line endpoint coordinates.

Returns:

coordinate to node map.

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

setObject

protected void setObject(Edge e,
 Object obj)

setObject

protected void setObject(Node n,
 Object obj)

useTolerance

protected boolean useTolerance()