/*
* 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 v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.geom.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryComponentFilter;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geom.LinearRing;
import org.locationtech.jts.geom.MultiLineString;
/**
* 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;
}
/**
* Extracts the linear components from a single {@link Geometry}
* and returns them as either a {@link LineString} or {@link MultiLineString}.
*
* @param geom the geometry from which to extract
* @return a linear geometry
*/
public static Geometry getGeometry(Geometry geom)
{
return geom.getFactory().buildGeometry(getLines(geom));
}
/**
* Extracts the linear components from a single {@link Geometry}
* and returns them as either a {@link LineString} or {@link MultiLineString}.
*
* @param geom the geometry from which to extract
* @param forceToLineString true if LinearRings should be converted to LineStrings
* @return a linear geometry
*/
public static Geometry getGeometry(Geometry geom, boolean forceToLineString)
{
return geom.getFactory().buildGeometry(getLines(geom, forceToLineString));
}
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
}
}