com.vividsolutions.jts.io.gml2.GMLWriter Maven / Gradle / Ivy
/*
* 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.io.gml2;
import java.io.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.util.Assert;
/**
* Writes {@link Geometry}s as XML fragments in GML2 format.
* Allows specifying the XML prefix, namespace and srsName
* of the emitted GML.
* Also allows adding custom root elements
* to support GML extensions such as KML.
* With appropriate settings for prefix (none) and custom root elements
* this class can be used to write out geometry in KML format.
*
* An example of the output that can be generated is:
*
*
*
*
* 6.03,8.17 7.697,6.959 8.333,5.0 7.697,3.041 6.03,1.83 3.97,1.83 2.303,3.041 1.667,5.0 2.303,6.959 3.97,8.17
*
*
*
*
*
* This class does not rely on any external XML libraries.
*
* @author David Zwiers, Vivid Solutions
* @author Martin Davis
*/
public class GMLWriter {
private final String INDENT = " ";
private int startingIndentIndex = 0;
private int maxCoordinatesPerLine = 10;
private boolean emitNamespace = false;
private boolean isRootTag = false;
private String prefix = GMLConstants.GML_PREFIX;
private String namespace = GMLConstants.GML_NAMESPACE;
private String srsName = null;
private String[] customElements = null;
/**
* Creates a writer which outputs GML with default settings.
* The defaults are:
*
* - the namespace prefix is gml:
*
- no namespace prefix declaration is written
*
- no srsName attribute is written
*
*/
public GMLWriter() {
}
/**
* Creates a writer which may emit the GML namespace prefix
* declaration in the geometry root element.
*
* @param emitNamespace trueif the GML namespace prefix declaration should be written
* in the geometry root element
*/
public GMLWriter(boolean emitNamespace) {
this.setNamespace(emitNamespace);
}
/**
* Specifies the namespace prefix to write on each GML tag.
* A null or blank prefix may be used to indicate no prefix.
*
* The default is to write gml: as the namespace prefix.
*
* @param prefix the namespace prefix to use (null or blank if none)
*/
public void setPrefix(String prefix) {
this.prefix = prefix;
}
/**
* Sets the value of the srsName attribute
* to be written into the root geometry tag.
* If the value is null or blank no srsName attribute will be written.
* The provided value must be a valid XML attribute value
* - it will not be XML-escaped.
*
* The default is not to write the srsName attribute.
*
* @param srsName the srsName attribute value
*/
public void setSrsName(String srsName) {
this.srsName = srsName;
}
/**
* Determines whether a GML namespace declaration will be written in the
* opening tag of geometries. Useful in XML-aware environments which
* parse the geometries before use, such as XSLT.
*
* @param emitNamespace true if the GML namespace prefix declaration
* should be written in the root geometry element
*/
public void setNamespace(boolean emitNamespace) {
this.emitNamespace = emitNamespace;
}
/**
* Specifies a list of custom elements
* which are written after the opening tag
* of the root element.
* The text contained in the string sequence should form valid XML markup.
* The specified strings are written one per line immediately after
* the root geometry tag line.
*
* For instance, this is useful for adding KML-specific geometry parameters
* such as <extrude>
*
* @param customElements a list of the custom element strings, or null if none
*/
public void setCustomElements(String[] customElements) {
this.customElements = customElements;
}
/**
* Sets the starting column index for pretty printing
*
* @param indent
*/
public void setStartingIndentIndex(int indent) {
if (indent < 0)
indent = 0;
startingIndentIndex = indent;
}
/**
* Sets the number of coordinates printed per line.
*
* @param num
*/
public void setMaxCoordinatesPerLine(int num) {
if (num < 1)
throw new IndexOutOfBoundsException(
"Invalid coordinate count per line, must be > 0");
maxCoordinatesPerLine = num;
}
/**
* Writes a {@link Geometry} in GML2 format to a String.
*
* @param geom
* @return String GML2 Encoded Geometry
*/
public String write(Geometry geom)
{
StringWriter writer = new StringWriter();
try {
write(geom, writer);
}
catch (IOException ex) {
Assert.shouldNeverReachHere();
}
return writer.toString();
}
/**
* Writes a {@link Geometry} in GML2 format into a {@link Writer}.
*
* @param geom Geometry to encode
* @param writer Stream to encode to.
* @throws IOException
*/
public void write(Geometry geom, Writer writer) throws IOException {
write(geom, writer, startingIndentIndex);
}
private void write(Geometry geom, Writer writer, int level)
throws IOException
{
isRootTag = true;
if (geom instanceof Point) {
writePoint((Point) geom, writer, level);
} else if (geom instanceof LineString) {
writeLineString((LineString) geom, writer, level);
} else if (geom instanceof Polygon) {
writePolygon((Polygon) geom, writer, level);
} else if (geom instanceof MultiPoint) {
writeMultiPoint((MultiPoint) geom, writer, level);
} else if (geom instanceof MultiLineString) {
writeMultiLineString((MultiLineString) geom, writer, level);
} else if (geom instanceof MultiPolygon) {
writeMultiPolygon((MultiPolygon) geom, writer, level);
} else if (geom instanceof GeometryCollection) {
writeGeometryCollection((GeometryCollection) geom, writer,
startingIndentIndex);
} else {
throw new IllegalArgumentException("Unhandled geometry type: "
+ geom.getGeometryType());
}
writer.flush();
}
// 1195156.78946687,382069.533723461 1195123.37289257,381985.763974674 1195120.22369473,381964.660533343 1195118.14929823,381942.597718511 1226890.26761027,1466433.47430292 1226880.59239079,1466427.03208053...>
* 2d and 3d aware.
*
* @param coords array of coordinates
* @throws IOException
*/
private void write(Coordinate[] coords, Writer writer, int level)
throws IOException {
startLine(level, writer);
startGeomTag(GMLConstants.GML_COORDINATES, null, writer);
int dim = 2;
if (coords.length > 0) {
if (!(Double.isNaN(coords[0].z)))
dim = 3;
}
boolean isNewLine = true;
for (int i = 0; i < coords.length; i++) {
if (isNewLine) {
startLine(level + 1, writer);
isNewLine = false;
}
if (dim == 2) {
writer.write("" + coords[i].x);
writer.write(coordinateSeparator);
writer.write("" + coords[i].y);
} else if (dim == 3) {
writer.write("" + coords[i].x);
writer.write(coordinateSeparator);
writer.write("" + coords[i].y);
writer.write(coordinateSeparator);
writer.write("" + coords[i].z);
}
writer.write(tupleSeparator);
// break output lines to prevent them from getting too long
if ((i + 1) % maxCoordinatesPerLine == 0 && i < coords.length - 1) {
writer.write("\n");
isNewLine = true;
}
}
if (!isNewLine)
writer.write("\n");
startLine(level, writer);
endGeomTag(GMLConstants.GML_COORDINATES, writer);
}
private void startLine(int level, Writer writer) throws IOException {
for (int i = 0; i < level; i++)
writer.write(INDENT);
}
private void startGeomTag(String geometryName, Geometry g, Writer writer)
throws IOException {
writer.write("<"
+ ((prefix == null || "".equals(prefix)) ? "" : prefix + ":"));
writer.write(geometryName);
writeAttributes(g, writer);
writer.write(">\n");
writeCustomElements(g, writer);
isRootTag = false;
}
private void writeAttributes(Geometry geom, Writer writer) throws IOException {
if (geom == null)
return;
if (! isRootTag)
return;
if (emitNamespace) {
writer.write(" xmlns"
+ ((prefix == null || "".equals(prefix)) ? "" : ":"+prefix )
+ "='" + namespace + "'");
}
if (srsName != null && srsName.length() > 0) {
writer.write(" " + GMLConstants.GML_ATTR_SRSNAME + "='" + srsName + "'");
// MD - obsoleted
// writer.write(geom.getSRID() + "");
}
}
private void writeCustomElements(Geometry geom, Writer writer) throws IOException {
if (geom == null) return;
if (! isRootTag) return;
if (customElements == null) return;
for (int i = 0; i < customElements.length; i++) {
writer.write(customElements[i]);
writer.write("\n");
}
}
private void endGeomTag(String geometryName, Writer writer)
throws IOException {
writer.write("\n");
}
private String prefix()
{
if (prefix == null || prefix.length() == 0)
return "";
return prefix + ":";
}
}