/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.geom.util;
import java.util.*;
import com.vividsolutions.jts.geom.*;
/**
* Extracts all the 1-dimensional ({@link LineString}) components from a {@link Geometry}.
* For polygonal geometries, this will extract all the component {@link LinearRing}s.
* If desired, <code>LinearRing</code>s can be forced to be returned as <code>LineString</code>s.
*
* @version 1.7
*/
public class LinearComponentExtracter
implements GeometryComponentFilter
{
/**
* Extracts the linear components from a single {@link Geometry}
* and adds them to the provided {@link Collection}.
*
* @param geoms the collection of geometries from which to extract linear components
* @param lines the collection to add the extracted linear components to
* @return the collection of linear components (LineStrings or LinearRings)
*/
public static Collection getLines(Collection geoms, Collection lines)
{
for (Iterator i = geoms.iterator(); i.hasNext(); ) {
Geometry g = (Geometry) i.next();
getLines(g, lines);
}
return lines;
}
/**
* Extracts the linear components from a single {@link Geometry}
* and adds them to the provided {@link Collection}.
*
* @param geoms the Collection of geometries from which to extract linear components
* @param lines the collection to add the extracted linear components to
* @param forceToLineString true if LinearRings should be converted to LineStrings
* @return the collection of linear components (LineStrings or LinearRings)
*/
public static Collection getLines(Collection geoms, Collection lines, boolean forceToLineString)
{
for (Iterator i = geoms.iterator(); i.hasNext(); ) {
Geometry g = (Geometry) i.next();
getLines(g, lines, forceToLineString);
}
return lines;
}
/**
* Extracts the linear components from a single {@link Geometry}
* and adds them to the provided {@link Collection}.
*
* @param geom the geometry from which to extract linear components
* @param lines the Collection to add the extracted linear components to
* @return the Collection of linear components (LineStrings or LinearRings)
*/
public static Collection getLines(Geometry geom, Collection lines)
{
if (geom instanceof LineString) {
lines.add(geom);
}
else {
geom.apply(new LinearComponentExtracter(lines));
}
return lines;
}
/**
* Extracts the linear components from a single {@link Geometry}
* and adds them to the provided {@link Collection}.
*
* @param geom the geometry from which to extract linear components
* @param lines the Collection to add the extracted linear components to
* @param forceToLineString true if LinearRings should be converted to LineStrings
* @return the Collection of linear components (LineStrings or LinearRings)
*/
public static Collection getLines(Geometry geom, Collection lines, boolean forceToLineString)
{
geom.apply(new LinearComponentExtracter(lines, forceToLineString));
return lines;
}
/**
* Extracts the linear components from a single geometry.
* If more than one geometry is to be processed, it is more
* efficient to create a single {@link LinearComponentExtracter} instance
* and pass it to multiple geometries.
*
* @param geom the geometry from which to extract linear components
* @return the list of linear components
*/
public static List getLines(Geometry geom)
{
return getLines(geom, false);
}
/**
* Extracts the linear components from a single geometry.
* If more than one geometry is to be processed, it is more
* efficient to create a single {@link LinearComponentExtracter} instance
* and pass it to multiple geometries.
*
* @param geom the geometry from which to extract linear components
* @param forceToLineString true if LinearRings should be converted to LineStrings
* @return the list of linear components
*/
public static List getLines(Geometry geom, boolean forceToLineString)
{
List lines = new ArrayList();
geom.apply(new LinearComponentExtracter(lines, forceToLineString));
return lines;
}
private Collection lines;
private boolean isForcedToLineString = false;
/**
* Constructs a LineExtracterFilter with a list in which to store LineStrings found.
*/
public LinearComponentExtracter(Collection lines)
{
this.lines = lines;
}
/**
* Constructs a LineExtracterFilter with a list in which to store LineStrings found.
*/
public LinearComponentExtracter(Collection lines, boolean isForcedToLineString)
{
this.lines = lines;
this.isForcedToLineString = isForcedToLineString;
}
/**
* Indicates that LinearRing components should be
* converted to pure LineStrings.
*
* @param isForcedToLineString true if LinearRings should be converted to LineStrings
*/
public void setForceToLineString(boolean isForcedToLineString)
{
this.isForcedToLineString = isForcedToLineString;
}
public void filter(Geometry geom)
{
if (isForcedToLineString && geom instanceof LinearRing) {
LineString line = geom.getFactory().createLineString( ((LinearRing) geom).getCoordinateSequence());
lines.add(line);
return;
}
// if not being forced, and this is a linear component
if (geom instanceof LineString)
lines.add(geom);
// else this is not a linear component, so skip it
}
}