/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2001-2006 Vivid Solutions
* (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.geometry.iso.topograph2D;
/**
* 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.
*
*
*
*
* @source $URL$
* @version 1.7.2
*
*/
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
*/
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.
*/
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.
*/
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.
*/
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.
*/
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
*/
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) {
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
*/
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();
}
}