to.networld.fbtosemweb.AbstractRDFExporter.java Source code

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Here is the source code for to.networld.fbtosemweb.AbstractRDFExporter.java

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/**
 * cas-webservice - to.networld.cas.ws
 *
 * Copyright (C) 2011 by Networld Project
 * Written by Alex Oberhauser <oberhauseralex@networld.to>
 * All Rights Reserved
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by 
 * the Free Software Foundation, version 3 of the License.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software.  If not, see <http://www.gnu.org/licenses/>
 */

package to.networld.fbtosemweb;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Namespace;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

/**
 * @author Alex Oberhauser
 */
public abstract class AbstractRDFExporter {
    protected Document rdfDocument;

    private static final int INDENT_SIZE = 4;
    private static final boolean EXPAND_EMPTY_ELEMENTS = false;

    public static Namespace RDF_NS = DocumentHelper.createNamespace("rdf",
            "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
    public static Namespace RDFS_NS = DocumentHelper.createNamespace("rdfs",
            "http://www.w3.org/2000/01/rdf-schema#");
    public static Namespace FOAF_NS = DocumentHelper.createNamespace("foaf", "http://xmlns.com/foaf/0.1/");
    public static Namespace DC_NS = DocumentHelper.createNamespace("dc", "http://purl.org/dc/elements/1.1/");
    public static Namespace DCT_NS = DocumentHelper.createNamespace("dct", "http://purl.org/dc/terms/");
    public static Namespace GEO_NS = DocumentHelper.createNamespace("geo",
            "http://www.w3.org/2003/01/geo/wgs84_pos#");
    public static Namespace SIOC_NS = DocumentHelper.createNamespace("sioc", "http://rdfs.org/sioc/ns#");

    public AbstractRDFExporter() {
        this.rdfDocument = DocumentHelper.createDocument();
        this.rdfDocument.setXMLEncoding("UTF-8");

        this.rdfDocument.addComment("Facebook to FOAF App (http://fbtofoaf.networld.to)");
        this.rdfDocument.addComment("(C) Alex Oberhauser - http://devnull.networld.to/foaf.rdf#me");
    }

    @Override
    public String toString() {
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        try {
            OutputFormat format = OutputFormat.createPrettyPrint();
            format.setIndentSize(INDENT_SIZE);
            format.setExpandEmptyElements(EXPAND_EMPTY_ELEMENTS);
            XMLWriter writer = new XMLWriter(os, format);
            writer.write(this.rdfDocument);
            return os.toString();
        } catch (IOException e) {
            return null;
        }
    }
}