GeometryEditor.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.geom.util;
import java.util.ArrayList;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.CoordinateSequence;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.GeometryCollection;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.LineString;
import org.locationtech.jts.geom.LinearRing;
import org.locationtech.jts.geom.MultiLineString;
import org.locationtech.jts.geom.MultiPoint;
import org.locationtech.jts.geom.MultiPolygon;
import org.locationtech.jts.geom.Point;
import org.locationtech.jts.geom.Polygon;
import org.locationtech.jts.util.Assert;
/**
* A class which supports creating new {@link Geometry}s
* which are modifications of existing ones,
* maintaining the same type structure.
* Geometry objects are intended to be treated as immutable.
* This class "modifies" Geometrys
* by traversing them, applying a user-defined
* {@link GeometryEditorOperation}, {@link CoordinateSequenceOperation} or {@link CoordinateOperation}
* and creating new Geometrys with the same structure but
* (possibly) modified components.
* <p>
* Examples of the kinds of modifications which can be made are:
* <ul>
* <li>the values of the coordinates may be changed.
* The editor does not check whether changing coordinate values makes the result Geometry invalid
* <li>the coordinate lists may be changed
* (e.g. by adding, deleting or modifying coordinates).
* The modified coordinate lists must be consistent with their original parent component
* (e.g. a <tt>LinearRing</tt> must always have at least 4 coordinates, and the first and last
* coordinate must be equal)
* <li>components of the original geometry may be deleted
* (e.g. holes may be removed from a Polygon, or LineStrings removed from a MultiLineString).
* Deletions will be propagated up the component tree appropriately.
* </ul>
* All changes must be consistent with the original Geometry's structure
* (e.g. a <tt>Polygon</tt> cannot be collapsed into a <tt>LineString</tt>).
* If changing the structure is required, use a {@link GeometryTransformer}.
* <p>
* This class supports creating an edited Geometry
* using a different <code>GeometryFactory</code> via the {@link #GeometryEditor(GeometryFactory)}
* constructor.
* Examples of situations where this is required is if the geometry is
* transformed to a new SRID and/or a new PrecisionModel.
* <p>
* <b>Usage Notes</b>
* <ul>
* <li>The resulting Geometry is not checked for validity.
* If validity needs to be enforced, the new Geometry's
* {@link Geometry#isValid} method should be called.
* <li>By default the UserData of the input geometry is not copied to the result.
* </ul>
*
* @see GeometryTransformer
* @see Geometry#isValid
*
* @version 1.7
*/
public class GeometryEditor
{
/**
* The factory used to create the modified Geometry.
* If <tt>null</tt> the GeometryFactory of the input is used.
*/
private GeometryFactory factory = null;
private boolean isUserDataCopied = false;
/**
* Creates a new GeometryEditor object which will create
* edited {@link Geometry}s with the same {@link GeometryFactory} as the input Geometry.
*/
public GeometryEditor()
{
}
/**
* Creates a new GeometryEditor object which will create
* edited {@link Geometry}s with the given {@link GeometryFactory}.
*
* @param factory the GeometryFactory to create edited Geometrys with
*/
public GeometryEditor(GeometryFactory factory)
{
this.factory = factory;
}
/**
* Sets whether the User Data is copied to the edit result.
* Only the object reference is copied.
*
* @param isUserDataCopied true if the input user data should be copied.
*/
public void setCopyUserData(boolean isUserDataCopied)
{
this.isUserDataCopied = isUserDataCopied;
}
/**
* Edit the input {@link Geometry} with the given edit operation.
* Clients can create subclasses of {@link GeometryEditorOperation} or
* {@link CoordinateOperation} to perform required modifications.
*
* @param geometry the Geometry to edit
* @param operation the edit operation to carry out
* @return a new {@link Geometry} which is the result of the editing (which may be empty)
*/
public Geometry edit(Geometry geometry, GeometryEditorOperation operation)
{
// nothing to do
if (geometry == null) return null;
Geometry result = editInternal(geometry, operation);
if (isUserDataCopied) {
result.setUserData(geometry.getUserData());
}
return result;
}
private Geometry editInternal(Geometry geometry, GeometryEditorOperation operation)
{
// if client did not supply a GeometryFactory, use the one from the input Geometry
if (factory == null)
factory = geometry.getFactory();
if (geometry instanceof GeometryCollection) {
return editGeometryCollection((GeometryCollection) geometry,
operation);
}
if (geometry instanceof Polygon) {
return editPolygon((Polygon) geometry, operation);
}
if (geometry instanceof Point) {
return operation.edit(geometry, factory);
}
if (geometry instanceof LineString) {
return operation.edit(geometry, factory);
}
Assert.shouldNeverReachHere("Unsupported Geometry class: " + geometry.getClass().getName());
return null;
}
private Polygon editPolygon(Polygon polygon,
GeometryEditorOperation operation) {
Polygon newPolygon = (Polygon) operation.edit(polygon, factory);
// create one if needed
if (newPolygon == null)
newPolygon = factory.createPolygon();
if (newPolygon.isEmpty()) {
//RemoveSelectedPlugIn relies on this behaviour. [Jon Aquino]
return newPolygon;
}
LinearRing shell = (LinearRing) edit(newPolygon.getExteriorRing(), operation);
if (shell == null || shell.isEmpty()) {
//RemoveSelectedPlugIn relies on this behaviour. [Jon Aquino]
return factory.createPolygon();
}
ArrayList holes = new ArrayList();
for (int i = 0; i < newPolygon.getNumInteriorRing(); i++) {
LinearRing hole = (LinearRing) edit(newPolygon.getInteriorRingN(i), operation);
if (hole == null || hole.isEmpty()) {
continue;
}
holes.add(hole);
}
return factory.createPolygon(shell,
(LinearRing[]) holes.toArray(new LinearRing[] { }));
}
private GeometryCollection editGeometryCollection(
GeometryCollection collection, GeometryEditorOperation operation) {
// first edit the entire collection
// MD - not sure why this is done - could just check original collection?
GeometryCollection collectionForType = (GeometryCollection) operation.edit(collection,
factory);
// edit the component geometries
ArrayList geometries = new ArrayList();
for (int i = 0; i < collectionForType.getNumGeometries(); i++) {
Geometry geometry = edit(collectionForType.getGeometryN(i), operation);
if (geometry == null || geometry.isEmpty()) {
continue;
}
geometries.add(geometry);
}
if (collectionForType.getClass() == MultiPoint.class) {
return factory.createMultiPoint((Point[]) geometries.toArray(
new Point[] { }));
}
if (collectionForType.getClass() == MultiLineString.class) {
return factory.createMultiLineString((LineString[]) geometries.toArray(
new LineString[] { }));
}
if (collectionForType.getClass() == MultiPolygon.class) {
return factory.createMultiPolygon((Polygon[]) geometries.toArray(
new Polygon[] { }));
}
return factory.createGeometryCollection((Geometry[]) geometries.toArray(
new Geometry[] { }));
}
/**
* A interface which specifies an edit operation for Geometries.
*
* @version 1.7
*/
public interface GeometryEditorOperation
{
/**
* Edits a Geometry by returning a new Geometry with a modification.
* The returned geometry may be:
* <ul>
* <li>the input geometry itself.
* The returned Geometry might be the same as the Geometry passed in.
* <li><code>null</code> if the geometry is to be deleted.
* </ul>
*
* @param geometry the Geometry to modify
* @param factory the factory with which to construct the modified Geometry
* (may be different to the factory of the input geometry)
* @return a new Geometry which is a modification of the input Geometry
* @return null if the Geometry is to be deleted completely
*/
Geometry edit(Geometry geometry, GeometryFactory factory);
}
/**
* A GeometryEditorOperation which does not modify
* the input geometry.
* This can be used for simple changes of
* GeometryFactory (including PrecisionModel and SRID).
*
* @author mbdavis
*
*/
public static class NoOpGeometryOperation
implements GeometryEditorOperation
{
public Geometry edit(Geometry geometry, GeometryFactory factory)
{
return geometry;
}
}
/**
* A {@link GeometryEditorOperation} which edits the coordinate list of a {@link Geometry}.
* Operates on Geometry subclasses which contains a single coordinate list.
*/
public abstract static class CoordinateOperation
implements GeometryEditorOperation
{
public final Geometry edit(Geometry geometry, GeometryFactory factory) {
if (geometry instanceof LinearRing) {
return factory.createLinearRing(edit(geometry.getCoordinates(),
geometry));
}
if (geometry instanceof LineString) {
return factory.createLineString(edit(geometry.getCoordinates(),
geometry));
}
if (geometry instanceof Point) {
Coordinate[] newCoordinates = edit(geometry.getCoordinates(),
geometry);
return factory.createPoint((newCoordinates.length > 0)
? newCoordinates[0] : null);
}
return geometry;
}
/**
* Edits the array of {@link Coordinate}s from a {@link Geometry}.
* <p>
* If it is desired to preserve the immutability of Geometrys,
* if the coordinates are changed a new array should be created
* and returned.
*
* @param coordinates the coordinate array to operate on
* @param geometry the geometry containing the coordinate list
* @return an edited coordinate array (which may be the same as the input)
*/
public abstract Coordinate[] edit(Coordinate[] coordinates,
Geometry geometry);
}
/**
* A {@link GeometryEditorOperation} which edits the {@link CoordinateSequence}
* of a {@link Geometry}.
* Operates on Geometry subclasses which contains a single coordinate list.
*/
public abstract static class CoordinateSequenceOperation
implements GeometryEditorOperation
{
public final Geometry edit(Geometry geometry, GeometryFactory factory) {
if (geometry instanceof LinearRing) {
return factory.createLinearRing(edit(
((LinearRing)geometry).getCoordinateSequence(),
geometry));
}
if (geometry instanceof LineString) {
return factory.createLineString(edit(
((LineString)geometry).getCoordinateSequence(),
geometry));
}
if (geometry instanceof Point) {
return factory.createPoint(edit(
((Point)geometry).getCoordinateSequence(),
geometry));
}
return geometry;
}
/**
* Edits a {@link CoordinateSequence} from a {@link Geometry}.
*
* @param coordSeq the coordinate array to operate on
* @param geometry the geometry containing the coordinate list
* @return an edited coordinate sequence (which may be the same as the input)
*/
public abstract CoordinateSequence edit(CoordinateSequence coordSeq,
Geometry geometry);
}
}