com.revolsys.jts.geomgraph

Class Label

java.lang.Object

com.revolsys.jts.geomgraph.Label

public class Label
extends Object

A Label indicates the topological relationship of a component of a topology graph to a given Geometry. This class supports labels for relationships to two Geometrys, which is sufficient for algorithms for binary operations.

Topology graphs support the concept of labeling nodes and edges in the graph. The label of a node or edge specifies its topological relationship to one or more geometries. (In fact, since JTS operations have only two arguments labels are required for only two geometries). A label for a node or edge has one or two elements, depending on whether the node or edge occurs in one or both of the input Geometrys. Elements contain attributes which categorize the topological location of the node or edge relative to the parent Geometry; that is, whether the node or edge is in the interior, boundary or exterior of the Geometry. Attributes have a value from the set {Interior, Boundary, Exterior}. In a node each element has a single attribute <On>. For an edge each element has a triplet of attributes <Left, On, Right>.

It is up to the client code to associate the 0 and 1 TopologyLocations with specific geometries.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
Label(int geomIndex, Location onLoc) Construct a Label with a single location for both Geometries.
Label(int geomIndex, Location onLoc, Location leftLoc, Location rightLoc) Construct a Label with On, Left and Right locations for both Geometries.
Label(Label lbl) Construct a Label with the same values as the argument Label.
Label(Location onLoc) Construct a Label with a single location for both Geometries.
Label(Location onLoc, Location leftLoc, Location rightLoc) Construct a Label with On, Left and Right locations for both Geometries.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	allPositionsEqual(int geomIndex, Location loc)
void	flip()
int	getGeometryCount()
Location	getLocation(int geomIndex)
Location	getLocation(int geomIndex, int posIndex)
boolean	isAnyNull(int geomIndex)
boolean	isArea()
boolean	isArea(int geomIndex)
boolean	isEqualOnSide(Label lbl, int side)
boolean	isLine(int geomIndex)
boolean	isNull(int geomIndex)
void	merge(Label lbl) Merge this label with another one.
void	setAllLocations(int geomIndex, Location location)
void	setAllLocationsIfNull(int geomIndex, Location location)
void	setAllLocationsIfNull(Location location)
void	setLocation(int geomIndex, int posIndex, Location location)
void	setLocation(int geomIndex, Location location)
void	toLine(int geomIndex) Converts one GeometryLocation to a Line location
static Label	toLineLabel(Label label)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Label

public Label(int geomIndex,
     Location onLoc)

Construct a Label with a single location for both Geometries. Initialize the location for the Geometry index.

Label

public Label(int geomIndex,
     Location onLoc,
     Location leftLoc,
     Location rightLoc)

Construct a Label with On, Left and Right locations for both Geometries. Initialize the locations for the given Geometry index.

Label

public Label(Label lbl)

Construct a Label with the same values as the argument Label.

Label

public Label(Location onLoc)

Construct a Label with a single location for both Geometries. Initialize the locations to Null

Label

public Label(Location onLoc,
     Location leftLoc,
     Location rightLoc)

Construct a Label with On, Left and Right locations for both Geometries. Initialize the locations for both Geometries to the given values.

Method Detail

toLineLabel

public static Label toLineLabel(Label label)

allPositionsEqual

public boolean allPositionsEqual(int geomIndex,
                        Location loc)

flip

public void flip()

getGeometryCount

public int getGeometryCount()

getLocation

public Location getLocation(int geomIndex)

getLocation

public Location getLocation(int geomIndex,
                   int posIndex)

isAnyNull

public boolean isAnyNull(int geomIndex)

isArea

public boolean isArea()

isArea

public boolean isArea(int geomIndex)

isEqualOnSide

public boolean isEqualOnSide(Label lbl,
                    int side)

isLine

public boolean isLine(int geomIndex)

isNull

public boolean isNull(int geomIndex)

merge

public void merge(Label lbl)

Merge this label with another one. Merging updates any null attributes of this label with the attributes from lbl

setAllLocations

public void setAllLocations(int geomIndex,
                   Location location)

setAllLocationsIfNull

public void setAllLocationsIfNull(int geomIndex,
                         Location location)

setAllLocationsIfNull

public void setAllLocationsIfNull(Location location)

setLocation

public void setLocation(int geomIndex,
               int posIndex,
               Location location)

setLocation

public void setLocation(int geomIndex,
               Location location)

toLine

public void toLine(int geomIndex)

Converts one GeometryLocation to a Line location

toString

public String toString()

Overrides:

toString in class Object