Btukfyl

I'm trying to use GeoTools to write SLDs on the fly for an application I am developing. But try as I might, I can't get the SLDs to be output.

Starting with an SLD that looks like this:

<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" version="1.0.0"

xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.0.0/StyledLayerDescriptor.xsd"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <NamedLayer>

        <Name>named_layer</Name>

        <UserStyle>

            <Name>style</Name>

            <IsDefault>true</IsDefault>

            <FeatureTypeStyle>

                <Rule>

                    <PointSymbolizer>

                        <Graphic>

                            <Mark>

                                <WellKnownName>circle</WellKnownName>

                                <Fill>

                                    <CssParameter name="fill">#00aa00</CssParameter>

                                </Fill>

                                <Stroke>

                                    <CssParameter name="stroke">#000000</CssParameter>

                                    <CssParameter name="stroke-width">0.15</CssParameter>

                                </Stroke>

                            </Mark>

                            <Size>8</Size>

                        </Graphic>

                    </PointSymbolizer>

                </Rule>

            </FeatureTypeStyle>

        </UserStyle>

    </NamedLayer>

</StyledLayerDescriptor>

I use the following code:

package com.example.sld;



import org.geotools.sld.SLDConfiguration;

import org.geotools.sld.bindings.SLD;

import org.geotools.styling.StyledLayerDescriptor;

import org.geotools.xml.Configuration;

import org.geotools.xml.Encoder;

import org.geotools.xml.Parser;

import org.xml.sax.SAXException;



import javax.xml.parsers.ParserConfigurationException;

import java.io.IOException;

import java.io.InputStream;



public class TestStyle {



    private String style;



    public TestStyle() {



        Configuration config = new SLDConfiguration();

        Parser parser = new Parser(config);



        InputStream is = getClass().getResourceAsStream("test-sld.xml");



        StyledLayerDescriptor sld = null;

        try {

            sld = (StyledLayerDescriptor) parser.parse(is);

        } catch (SAXException e) {

            e.printStackTrace();

        } catch (ParserConfigurationException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }



        Configuration configuration = new SLDConfiguration();

        Encoder encoder = new Encoder(configuration);

        encoder.setOmitXMLDeclaration(true);

        try {

            this.style = encoder.encodeAsString(sld, SLD.STYLEDLAYERDESCRIPTOR);

        } catch (IOException e) {

            e.printStackTrace();

        }



        this.style = new String();



    }

}

The SLD parses OK. I can inspect its structure in my debugger and it is read correctly. But on encoding, the resultant SLD is empty:

<sld:StyledLayerDescriptor xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ogc="http://www.opengis.net/ogc" xmlns:sld="http://www.opengis.net/sld" xmlns:xlink="http://www.w3.org/1999/xlink"/>

What am I doing wrong?

(Version of GeoTools is 20.1, following the guide here: http://docs.geotools.org/latest/userguide/library/xml/style.html#encoder)

Thanks in advance

Your approach would work if you had a version 1.1.0 SLD (or more properly an SE) document, and if you used a import org.geotools.sld.v1_1.SLD object to pass to the encoder. However you have a version 1.0.0 SLD document so you need to use a
SLDTransformer class to output your style objects. So something like:

ByteArrayOutputStream bos = new ByteArrayOutputStream();

SLDTransformer transformer = new SLDTransformer();

transformer.setIndentation(2);

transformer.transform(sld, bos);

String style = bos.toString();

System.out.println(style);