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/*
* 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;
/**
* Models an OGC SFS LinearRing.
* A LinearRing is a {@link LineString} which is both closed and simple.
* In other words,
* the first and last coordinate in the ring must be equal,
* and the interior of the ring must not self-intersect.
* Either orientation of the ring is allowed.
*
* A ring must have either 0 or 4 or more points.
* The first and last points must be equal (in 2D).
* If these conditions are not met, the constructors throw
* an {@link IllegalArgumentException}
*
* @version 1.7
*/
public class LinearRing extends LineString
{
/**
* The minimum number of vertices allowed in a valid non-empty ring (= 4).
* Empty rings with 0 vertices are also valid.
*/
public static final int MINIMUM_VALID_SIZE = 4;
private static final long serialVersionUID = -4261142084085851829L;
/**
* Constructs a LinearRing with the given points.
*
*@param points points forming a closed and simple linestring, or
* null or an empty array to create the empty geometry.
* This array must not contain null elements.
*
*@param precisionModel the specification of the grid of allowable points
* for this LinearRing
*@param SRID the ID of the Spatial Reference System used by this
* LinearRing
* @throws IllegalArgumentException if the ring is not closed, or has too few points
*
* @deprecated Use GeometryFactory instead
*/
public LinearRing(Coordinate points[], PrecisionModel precisionModel,
int SRID) {
this(points, new GeometryFactory(precisionModel, SRID));
validateConstruction();
}
/**
* This method is ONLY used to avoid deprecation warnings.
* @param points
* @param factory
* @throws IllegalArgumentException if the ring is not closed, or has too few points
*/
private LinearRing(Coordinate points[], GeometryFactory factory) {
this(factory.getCoordinateSequenceFactory().create(points), factory);
}
/**
* Constructs a LinearRing with the vertices
* specifed by the given {@link CoordinateSequence}.
*
*@param points a sequence points forming a closed and simple linestring, or
* null to create the empty geometry.
*
* @throws IllegalArgumentException if the ring is not closed, or has too few points
*
*/
public LinearRing(CoordinateSequence points, GeometryFactory factory) {
super(points, factory);
validateConstruction();
}
private void validateConstruction() {
if (!isEmpty() && ! super.isClosed()) {
throw new IllegalArgumentException("Points of LinearRing do not form a closed linestring");
}
if (getCoordinateSequence().size() >= 1 && getCoordinateSequence().size() < MINIMUM_VALID_SIZE) {
throw new IllegalArgumentException("Invalid number of points in LinearRing (found "
+ getCoordinateSequence().size() + " - must be 0 or >= 4)");
}
}
/**
* Returns Dimension.FALSE, since by definition LinearRings do
* not have a boundary.
*
* @return Dimension.FALSE
*/
public int getBoundaryDimension() {
return Dimension.FALSE;
}
/**
* Tests whether this ring is closed.
* Empty rings are closed by definition.
*
* @return true if this ring is closed
*/
public boolean isClosed() {
if (isEmpty()) {
// empty LinearRings are closed by definition
return true;
}
return super.isClosed();
}
public String getGeometryType() {
return "LinearRing";
}
public Geometry reverse()
{
CoordinateSequence seq = (CoordinateSequence) points.clone();
CoordinateSequences.reverse(seq);
LinearRing rev = getFactory().createLinearRing(seq);
return rev;
}
}