Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2013 gvSIG Association.

 *

 * 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 3

 * 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.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.remoteclient.wcs;

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;

/**

 *

 * @author jaume dominguez faus

 *

 */

public class WCSProtocolHandlerFactory {

        public org.gvsig.remoteclient.wcs.WCSProtocolHandler wCSProtocolHandler;

        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 WCSClient'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 WCSProtocolHandler negotiate(String host) throws ConnectException, IOException {

                if (supportedVersions.size() == 0)

                {

                        return null;

                }

                try

                {

                        String highestVersionSupportedByServer  = getSuitableWCSVersion(host,"");

                        if (supportedVersions.contains(highestVersionSupportedByServer))

                        {

                                // we support the highest version supported by the server

                                // this is the best case

                                return createVersionDriver(highestVersionSupportedByServer);

                        }

                        else

                        {

                                // in case we dont support the highest version from the server

                                // we start the negotiation process in which we have to get the higest version

                                // the WCS supports and we are able to read.

                                Iterator iVersion = supportedVersions.iterator();

                                String wcsVersion;

                                String gvSIGVersion;

                                while (iVersion.hasNext()) {

                                        gvSIGVersion = (String)iVersion.next();

                                        wcsVersion = getSuitableWCSVersion(host,gvSIGVersion);

                                        //TODO:

                                        //compare with the version returned by the WMS!!!!!

                                        // send GetCapabilities and read the version to compare.

                                        int res = wcsVersion.compareTo(gvSIGVersion);

                                        if (res == 0) { //Si es la misma que nuestra version

                                                return createVersionDriver(gvSIGVersion);

                                        } else if (res > 0) { //Si es mayor que nuestra version

                                                throw new Exception("Server Version too high: " + wcsVersion);

                                        } else { //Si es menor que nuestra version

                                                //Obtenemos la primera version menor o igual que tengamos

                                                String lowerVersion = WCSProtocolHandlerFactory.getDriverVersion(wcsVersion, iVersion);

                                                if (lowerVersion == null) { //Si no hay ninguna

                                                        throw new Exception("Lowest server version is " + wcsVersion);

                                                } else {

                                                        if (lowerVersion.equals(wcsVersion)) {

                                                                return createVersionDriver(lowerVersion);

                                                        } else { //Si hay una version menor que la que retorno el servidor

                                                                //iV = lower;

                                                        }

                                                }

                                        }

                                }

                        }//case we had to start the negotiation process.

                        return null; // if it did not find any suitable version.

                }

                catch(ConnectException conEx)

                {

                        throw conEx;

                }

                catch(IOException ioEx)

                {

                        throw ioEx;

                }

                catch(Exception e)

                {

//                        e.printStackTrace();

                        return null;

                }

        }

        /**

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

         * if the version parameter is null, the WCS 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 getSuitableWCSVersion(String host, String _version) throws ConnectException, IOException {

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

                String version = new String();

                StringReader reader = null;

                //InputStreamReader reader;

                //InputStream is = null;

                DataInputStream dis = null;

                try {

                        URL url = new URL(request);

                        byte[] buffer = new byte[1024];//new byte[1024*256];

//                        is = url.openStream();

//                        reader = new InputStreamReader(is);

                        //int numberOfBytes = is.read(buffer);

                        //String readed = new String(buffer);

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

                        dis.readFully(buffer);

                        reader = new StringReader(new String(buffer));

                        KXmlParser kxmlParser = null;

                        kxmlParser = new KXmlParser();

                        kxmlParser.setInput(reader);

                        kxmlParser.nextTag();

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

                                if ((kxmlParser.getName().compareTo(CapabilitiesTags.WCS_CAPABILITIES_ROOT1_0_0)==0)) {

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

                                }

                        }

                        // do not forget to close the Stream.

                        reader.close();

                        dis.close();

                        return version;

                } catch(ConnectException conEx) {

                        throw new ConnectException(conEx.getMessage());

                } catch(IOException ioEx) {

                        throw new IOException(ioEx.getMessage());

                } 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 WCSDriver class.

         *

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

         * @return WCSDriver.

         */

        private static WCSProtocolHandler createVersionDriver(String version) {

                try {

                        Class driver;

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

                        driver = Class.forName("org.gvsig.remoteclient.wcs.wcs_"+version+".WCSProtocolHandler" + version);

                        return (WCSProtocolHandler)driver.newInstance();

                } catch (Exception e) {

                        e.printStackTrace();

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

                        return null;

                }

        }

}