RemoteMapCatalog.java

/**
 * OrbisGIS is a java GIS application dedicated to research in GIScience.
 * OrbisGIS is developed by the GIS group of the DECIDE team of the 
 * Lab-STICC CNRS laboratory, see <http://www.lab-sticc.fr/>.
 *
 * The GIS group of the DECIDE team is located at :
 *
 * Laboratoire Lab-STICC – CNRS UMR 6285
 * Equipe DECIDE
 * UNIVERSITÉ DE BRETAGNE-SUD
 * Institut Universitaire de Technologie de Vannes
 * 8, Rue Montaigne - BP 561 56017 Vannes Cedex
 * 
 * OrbisGIS is distributed under GPL 3 license.
 *
 * Copyright (C) 2007-2014 CNRS (IRSTV FR CNRS 2488)
 * Copyright (C) 2015-2017 CNRS (Lab-STICC UMR CNRS 6285)
 *
 * This file is part of OrbisGIS.
 *
 * OrbisGIS 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, either version 3 of the License, or (at your option) any later
 * version.
 *
 * OrbisGIS 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
 * OrbisGIS. If not, see <http://www.gnu.org/licenses/>.
 *
 * For more information, please consult: <http://www.orbisgis.org/>
 * or contact directly:
 * info_at_ orbisgis.org
 */
package org.orbisgis.coremap.layerModel.mapcatalog;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import org.apache.commons.lang3.StringEscapeUtils;
import org.xnap.commons.i18n.I18n;
import org.xnap.commons.i18n.I18nFactory;

/**
 * The remote map catalog is a Representational State Transfer Map Catalog client.
 * All informations 
 * @author Nicolas Fortin
 */
public class RemoteMapCatalog {
        private ConnectionProperties cParams;
        private static final I18n I18N = I18nFactory.getI18n(RemoteMapCatalog.class);
        
        /**
         * Constructor
         * @param connectionProperties Connection properties to the remote MapCatalog
         */
        public RemoteMapCatalog(ConnectionProperties connectionProperties) {
                this.cParams = connectionProperties;
        }
        
        /**
         * Read the parser and feed the provided list with workspaces
         * @param workspaces Writable, empty list of workspaces
         * @param parser Opened parser
         * @throws XMLStreamException 
         */
        public void parseXML(List<Workspace> workspaces,XMLStreamReader parser) throws XMLStreamException {
                List<String> hierarchy = new ArrayList<String>();
                // Hold workspace name
                StringBuilder characters = new StringBuilder();
                // Starting with a valid event, iterating while the parser
                // does not reach the end document XML tag
                for (int event = parser.next();
                        event != XMLStreamConstants.END_DOCUMENT;
                        event = parser.next()) {
                        // For each XML elements
                        switch(event) {
                                case XMLStreamConstants.START_ELEMENT:
                                        hierarchy.add(parser.getLocalName());
                                        break;
                                case XMLStreamConstants.END_ELEMENT:
                                        if(RemoteCommons.endsWith(hierarchy,"workspaces","workspace","name")) {
                                                workspaces.add(new Workspace(cParams,characters.toString().trim()));
                                        }
                                        hierarchy.remove(hierarchy.size()-1);
                                        characters = new StringBuilder(); // Clear the string buffer
                                        break;
                                case XMLStreamConstants.CHARACTERS:
                                        characters.append(StringEscapeUtils.unescapeHtml4(parser.getText()));
                                        break;
                        }                               
                }                
        }

        /**
         * Request the workspaces synchronously.
         * This call may take a long time to execute.
         * @return A list of workspaces
         * @throws IOException The request fail
         */
        public List<Workspace> getWorkspaces() throws IOException {
                List<Workspace> workspaces = new ArrayList<Workspace>();
                // Construct request
                URL requestWorkspacesURL =
                        new URL(RemoteCommons.getUrlWorkspaceList(cParams));
                // Establish connection
                HttpURLConnection connection = (HttpURLConnection) requestWorkspacesURL.openConnection();
                connection.setRequestMethod("GET");
                connection.setConnectTimeout(cParams.getConnectionTimeOut());
                if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                        throw new IOException(I18N.tr("HTTP Error {0} message : {1}", connection.getResponseCode(), connection.getResponseMessage()));
                }

                // Read the response content
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(
                        connection.getInputStream(),
                        RemoteCommons.getConnectionCharset(connection)));

                //"Content-Type" "text/xml; charset=utf-8"
                XMLInputFactory factory = XMLInputFactory.newInstance();

                // Parse Data
                XMLStreamReader parser;
                try {
                        parser = factory.createXMLStreamReader(in);
                        // Fill workspaces
                        parseXML(workspaces, parser);
                        parser.close();
                } catch (XMLStreamException ex) {
                        throw new IOException(I18N.tr("Invalid XML content"), ex);
                }
                return workspaces;
        }
}