Label.java
/*
* Copyright (c) 2016 Vivid Solutions.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.geomgraph;
import org.locationtech.jts.geom.Location;
import org.locationtech.jts.geom.Position;
/**
* A <code>Label</code> indicates the topological relationship of a component
* of a topology graph to a given <code>Geometry</code>.
* This class supports labels for relationships to two <code>Geometry</code>s,
* which is sufficient for algorithms for binary operations.
* <P>
* 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 <code>Geometry</code>s. Elements contain attributes which categorize the
* topological location of the node or edge relative to the parent
* <code>Geometry</code>; that is, whether the node or edge is in the interior,
* boundary or exterior of the <code>Geometry</code>. Attributes have a value
* from the set <code>{Interior, Boundary, Exterior}</code>. In a node each
* element has a single attribute <code><On></code>. For an edge each element has a
* triplet of attributes <code><Left, On, Right></code>.
* <P>
* It is up to the client code to associate the 0 and 1 <code>TopologyLocation</code>s
* with specific geometries.
* @version 1.7
*
*/
public class Label {
// converts a Label to a Line label (that is, one with no side Locations)
public static Label toLineLabel(Label label)
{
Label lineLabel = new Label(Location.NONE);
for (int i = 0; i < 2; i++) {
lineLabel.setLocation(i, label.getLocation(i));
}
return lineLabel;
}
TopologyLocation elt[] = new TopologyLocation[2];
/**
* Construct a Label with a single location for both Geometries.
* Initialize the locations to Null
*
* @param onLoc On location
*/
public Label(int onLoc)
{
elt[0] = new TopologyLocation(onLoc);
elt[1] = new TopologyLocation(onLoc);
}
/**
* Construct a Label with a single location for both Geometries.
* Initialize the location for the Geometry index.
*
* @param geomIndex Geometry index
* @param onLoc On location
*/
public Label(int geomIndex, int onLoc)
{
elt[0] = new TopologyLocation(Location.NONE);
elt[1] = new TopologyLocation(Location.NONE);
elt[geomIndex].setLocation(onLoc);
}
/**
* Construct a Label with On, Left and Right locations for both Geometries.
* Initialize the locations for both Geometries to the given values.
*
* @param onLoc On location
* @param rightLoc Right location
* @param leftLoc Left location
*/
public Label(int onLoc, int leftLoc, int rightLoc)
{
elt[0] = new TopologyLocation(onLoc, leftLoc, rightLoc);
elt[1] = new TopologyLocation(onLoc, leftLoc, rightLoc);
}
/**
* Construct a Label with On, Left and Right locations for both Geometries.
* Initialize the locations for the given Geometry index.
*
* @param geomIndex Geometry index
* @param onLoc On location
* @param rightLoc Right location
* @param leftLoc Left location
*/
public Label(int geomIndex, int onLoc, int leftLoc, int rightLoc)
{
elt[0] = new TopologyLocation(Location.NONE, Location.NONE, Location.NONE);
elt[1] = new TopologyLocation(Location.NONE, Location.NONE, Location.NONE);
elt[geomIndex].setLocations(onLoc, leftLoc, rightLoc);
}
/**
* Construct a Label with the same values as the argument Label.
*
* @param lbl Label
*/
public Label(Label lbl)
{
elt[0] = new TopologyLocation(lbl.elt[0]);
elt[1] = new TopologyLocation(lbl.elt[1]);
}
public void flip()
{
elt[0].flip();
elt[1].flip();
}
public int getLocation(int geomIndex, int posIndex) { return elt[geomIndex].get(posIndex); }
public int getLocation(int geomIndex) { return elt[geomIndex].get(Position.ON); }
public void setLocation(int geomIndex, int posIndex, int location)
{
elt[geomIndex].setLocation(posIndex, location);
}
public void setLocation(int geomIndex, int location)
{
elt[geomIndex].setLocation(Position.ON, location);
}
public void setAllLocations(int geomIndex, int location)
{
elt[geomIndex].setAllLocations(location);
}
public void setAllLocationsIfNull(int geomIndex, int location)
{
elt[geomIndex].setAllLocationsIfNull(location);
}
public void setAllLocationsIfNull(int location)
{
setAllLocationsIfNull(0, location);
setAllLocationsIfNull(1, location);
}
/**
* Merge this label with another one.
* Merging updates any null attributes of this label with the attributes from lbl.
*
* @param lbl Label to merge
s */
public void merge(Label lbl)
{
for (int i = 0; i < 2; i++) {
if (elt[i] == null && lbl.elt[i] != null) {
elt[i] = new TopologyLocation(lbl.elt[i]);
}
else {
elt[i].merge(lbl.elt[i]);
}
}
}
public int getGeometryCount()
{
int count = 0;
if (! elt[0].isNull()) count++;
if (! elt[1].isNull()) count++;
return count;
}
public boolean isNull(int geomIndex) { return elt[geomIndex].isNull(); }
public boolean isAnyNull(int geomIndex) { return elt[geomIndex].isAnyNull(); }
public boolean isArea() { return elt[0].isArea() || elt[1].isArea(); }
public boolean isArea(int geomIndex)
{
/* Testing
if (elt[0].getLocations().length != elt[1].getLocations().length) {
System.out.println(this);
}
*/
return elt[geomIndex].isArea();
}
public boolean isLine(int geomIndex) { return elt[geomIndex].isLine(); }
public boolean isEqualOnSide(Label lbl, int side)
{
return
this.elt[0].isEqualOnSide(lbl.elt[0], side)
&& this.elt[1].isEqualOnSide(lbl.elt[1], side);
}
public boolean allPositionsEqual(int geomIndex, int loc)
{
return elt[geomIndex].allPositionsEqual(loc);
}
/**
* Converts one GeometryLocation to a Line location
* @param geomIndex geometry location
*/
public void toLine(int geomIndex)
{
if (elt[geomIndex].isArea())
elt[geomIndex] = new TopologyLocation(elt[geomIndex].location[0]);
}
public String toString()
{
StringBuffer buf = new StringBuffer();
if (elt[0] != null) {
buf.append("A:");
buf.append(elt[0].toString());
}
if (elt[1] != null) {
buf.append(" B:");
buf.append(elt[1].toString());
}
return buf.toString();
}
}