| gvSIG desktop 1

/* gvSIG. Geographic Information System of the Valencian Government

*

* Copyright (C) 2007-2008 Infrastructures and Transports Department

* of the Valencian Government (CIT)

*

* 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; either version 2

* of the License, or (at your option) any later version.

*

* 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 program; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

* MA  02110-1301, USA.

*

*/

package org.gvsig.remoteclient.wmts;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.StringReader;

import java.net.ConnectException;

import java.net.URL;

import java.util.ArrayList;

import java.util.Iterator;

import org.kxml2.io.KXmlParser;

import org.xmlpull.v1.XmlPullParserException;

import org.gvsig.remoteclient.utils.CapabilitiesTags;

/**

 * This factory builds a new handler depending on the supported protocol.

 * This protocol could be negotiated with the server. Now only 1.0.0 version

 * is supported.

 * 

 * @author Nacho Brodin (nachobrodin@gmail.com)

 */

public class WMTSProtocolHandlerFactory {

        public org.gvsig.remoteclient.wms.WMSProtocolHandler wMSProtocolHandler;

        private static ArrayList supportedVersions = new ArrayList();

        static {

                supportedVersions.add("1.0.0");

        }

        /**

     * M?todo que dada una respuesta de getCapabilities y un iterador sobre una

     * coleccion de WMSClient's ordenada descendentemente devuelve el cliente

     * cuya version es igual o inmediatamente inferior

     *

     * @param caps Capabilities con la respuesta del servidor

     * @param clients Iterador de conjunto ordenado descendientemente

     *

     * @return cliente cuya version es igual o inmediatamente inferior

     * @throws IllegalAccessException

     * @throws InstantiationException

     *

     */

        private static String getDriverVersion(String version, Iterator clients) throws InstantiationException, IllegalAccessException {

        while (clients.hasNext()) {

            String clientVersion = (String)clients.next();

            int ret = version.compareTo(clientVersion);

            if (ret >= 0) {

                return clientVersion;

            }

        }

        return null;

    }

    /**

     * Establece la versi?n con la que se comunicar? con el servidor y devuelve

     * el objeto Capabilities obtenido con dicha versi?n

     *

     * @param host maquina con la que se negocia

     *

     * @return instancia de un cliente capaz de negociar con el host que se

     *         pasa como par?metro

     */

    public static WMTSProtocolHandler negotiate(String host) throws ConnectException, IOException {

            String highestVersionSupportedByServer  = getSuitableWMTSVersion(host, "");

            if (supportedVersions.contains(highestVersionSupportedByServer)) {

                    //we support the highest version supported by the server

                    // this is the best case

                    return createVersionDriver(highestVersionSupportedByServer);

            }

            return null;

    }

     /**

      * Sends a GetCapabilities to the WMTS server to get the version

      * if the version parameter is null, the WMTS will return the highest version supported

      * if not it will return the lower highest version than the one requested.

      * @param host

      * @param version

      * @return suitable version supported by the server

      */

     private static String getSuitableWMTSVersion(String host, String _version) throws ConnectException, IOException {

             String request = WMTSProtocolHandler.buildCapabilitiesSuitableVersionRequest(host, _version);

             String version = "";

             StringReader reader = null;

             DataInputStream dis = null;

             try {

                     URL url = new URL(request);

                     byte[] buffer = new byte[1024];

                     dis = new DataInputStream(url.openStream());

                     dis.readFully(buffer);

                     String string = new String(buffer);

                     int a = string.toLowerCase().indexOf("<?xml");

                     if (a !=-1)

                             string = string.substring(a, string.length());

                     reader = new StringReader(string);

                     KXmlParser kxmlParser = null;

                     kxmlParser = new KXmlParser();

                     kxmlParser.setInput(reader);

                     kxmlParser.nextTag();

                     if ( kxmlParser.getEventType() != KXmlParser.END_DOCUMENT ) {

                             if ((kxmlParser.getName().compareTo(CapabilitiesTags.WMTS_CAPABILITIES) == 0)) {

                                     version = kxmlParser.getAttributeValue("", CapabilitiesTags.VERSION);

                             }

                     }

                     // do not forget to close the Stream.

                     reader.close();

                     dis.close();

                     return version;

             } catch(XmlPullParserException xmlEx) {

                     xmlEx.printStackTrace();

                     return "";

             } finally {

                     if (reader != null) {

                             try {

                                     reader.close();

                             } catch(Exception ex) {

                                     ex.printStackTrace();

                             }

                     }

                     if (dis != null) {

                             try {

                                     dis.close();

                             } catch(Exception ex) {

                                     ex.printStackTrace();

                             }

                     }

             }

     }

     /**

      * It creates an instance of a WMSDriver class.

      *

      * @param String, with the version of the driver to be created

      * @return WMSDriver.

      */

     private static WMTSProtocolHandler createVersionDriver(String version) {

             try {

                     Class driver;

                     version = version.replace('.', '_');

                     driver = Class.forName("org.gvsig.remoteclient.wmts.wmts_" + version + ".WMTSProtocolHandler" + version);

                     return (WMTSProtocolHandler)driver.newInstance();

             } catch (Exception e) {

                     e.printStackTrace();

                     //throw new Exception("WMSDriverFactory. Unknown driver version " + e);

                     return null;

             }

     }

}