Class GeometryMapper

1	/*
2	* Copyright (c) 2016 Martin Davis.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12	package org.locationtech.jts.geom.util;
13
14	import java.util.ArrayList;
15	import java.util.Collection;
16	import java.util.Iterator;
17	import java.util.List;
18
19	import org.locationtech.jts.geom.Geometry;
20	import org.locationtech.jts.geom.GeometryCollection;
21
22	/**
23	* Methods to map various collections
24	* of {@link Geometry}s
25	* via defined mapping functions.
26	*
27	* @author Martin Davis
28	*
29	*/
30	public class GeometryMapper
31	{
32	/**
33	* Maps the members of a {@link Geometry}
34	* (which may be atomic or composite)
35	* into another <tt>Geometry</tt> of most specific type.
36	* <tt>null</tt> results are skipped.
37	* In the case of hierarchical {@link GeometryCollection}s,
38	* only the first level of members are mapped.
39	*
40	* @param geom the input atomic or composite geometry
41	* @param op the mapping operation
42	* @return a result collection or geometry of most specific type
43	*/
44	public static Geometry map(Geometry geom, MapOp op)
45	{
46	List mapped = new ArrayList();
47	for (int i = 0; i < geom.getNumGeometries(); i++) {
48	Geometry g = op.map(geom.getGeometryN(i));
49	if (g != null)
50	mapped.add(g);
51	}
52	return geom.getFactory().buildGeometry(mapped);
53	}
54
55	public static Collection map(Collection geoms, MapOp op)
56	{
57	List mapped = new ArrayList();
58	for (Iterator i = geoms.iterator(); i.hasNext(); ) {
59	Geometry g = (Geometry) i.next();
60	Geometry gr = op.map(g);
61	if (gr != null)
62	mapped.add(gr);
63	}
64	return mapped;
65	}
66
67	/**
68	* An interface for geometry functions used for mapping.
69	*
70	* @author Martin Davis
71	*
72	*/
73	public interface MapOp
74	{
75	/**
76	* Computes a new geometry value.
77	*
78	* @param g the input geometry
79	* @return a result geometry
80	*/
81	Geometry map(Geometry g);
82	}
83	}
84