Class GMLReader

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
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.io.gml2;
13
14	import java.io.IOException;
15	import java.io.Reader;
16	import java.io.StringReader;
17
18	import javax.xml.parsers.ParserConfigurationException;
19	import javax.xml.parsers.SAXParser;
20	import javax.xml.parsers.SAXParserFactory;
21
22	import org.locationtech.jts.geom.Geometry;
23	import org.locationtech.jts.geom.GeometryCollection;
24	import org.locationtech.jts.geom.GeometryFactory;
25	import org.locationtech.jts.geom.PrecisionModel;
26	import org.xml.sax.InputSource;
27	import org.xml.sax.SAXException;
28	import org.xml.sax.helpers.DefaultHandler;
29
30
31	/**
32	* Reads a GML2 geometry from an XML fragment into a {@link Geometry}.
33	* <p>
34	* An example of the GML2 format handled is:
35	* <pre>
36	* <LineString>
37	* <coordinates>
38	* 24824.045318333192,38536.15071012041
39	* 26157.378651666528,37567.42733944659 26666.666,36000.0
40	* 26157.378651666528,34432.57266055341
41	* 24824.045318333192,33463.84928987959
42	* 23175.954681666804,33463.84928987959
43	* 21842.621348333472,34432.57266055341 21333.333,36000.0
44	* 21842.621348333472,37567.42733944659
45	* 23175.954681666808,38536.15071012041
46	* </coordinates>
47	* </LineString>
48	* </pre>
49	*
50	* The reader ignores namespace prefixes,
51	* and disables both the validation and namespace options on the <tt>SAXParser</tt>.
52	* This class requires the presence of a SAX Parser available via the
53	* {@link javax.xml.parsers.SAXParserFactory#newInstance()}
54	* method.
55	* <p>
56	* A specification of the GML XML format
57	* can be found at the OGC web site: <a href='http://www.opengeospatial.org/'>http://www.opengeospatial.org/</a>.
58	* <p>
59	* It is the caller's responsibility to ensure that the supplied {@link PrecisionModel}
60	* matches the precision of the incoming data.
61	* If a lower precision for the data is required, a subsequent
62	* process must be run on the data to reduce its precision.
63	* <p>
64	* To parse and build geometry directly from a SAX stream, see {@link GMLHandler}.
65	*
66	* @author David Zwiers, Vivid Solutions.
67	*
68	* @see GMLHandler
69	*/
70	public class GMLReader
71	{
72
73	/**
74	* Reads a GML2 Geometry from a <tt>String</tt> into a single {@link Geometry}
75	*
76	* If a collection of geometries is found, a {@link GeometryCollection} is returned.
77	*
78	* @param gml The GML String to parse
79	* @param geometryFactory When null, a default will be used.
80	* @return the resulting JTS Geometry
81	*
82	* @throws ParserConfigurationException
83	* @throws IOException
84	* @throws SAXException
85	*
86	* @see #read(Reader, GeometryFactory)
87	*/
88	public Geometry read(String gml, GeometryFactory geometryFactory) throws SAXException, IOException, ParserConfigurationException{
89	return read(new StringReader(gml),geometryFactory);
90	}
91
92	/**
93	* Reads a GML2 Geometry from a {@link Reader} into a single {@link Geometry}
94	*
95	* If a collection of Geometries is found, a {@link GeometryCollection} is returned.
96	*
97	* @param reader The input source
98	* @param geometryFactory When null, a default will be used.
99	* @return The resulting JTS Geometry
100	* @throws SAXException
101	* @throws IOException
102	*/
103	public Geometry read(Reader reader, GeometryFactory geometryFactory) throws SAXException, IOException, ParserConfigurationException{
104	SAXParserFactory fact = SAXParserFactory.newInstance();
105
106	fact.setNamespaceAware(false);
107	fact.setValidating(false);
108
109	SAXParser parser = fact.newSAXParser();
110
111	if(geometryFactory == null)
112	geometryFactory = new GeometryFactory();
113
114	GMLHandler gh = new GMLHandler(geometryFactory,null);
115	parser.parse(new InputSource(reader), (DefaultHandler)gh);
116
117	return gh.getGeometry();
118	}
119
120	}
121