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.wms;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.StringReader;

import java.net.ConnectException;

import java.net.URL;

import java.net.URLConnection;

import java.util.ArrayList;

import java.util.Iterator;

import org.gvsig.remoteclient.utils.CapabilitiesTags;

import org.kxml2.io.KXmlParser;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.xmlpull.v1.XmlPullParserException;

public class WMSProtocolHandlerFactory {

    private static final Logger logger = LoggerFactory.getLogger(WMSProtocolHandlerFactory.class);

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

    private static ArrayList supportedVersions = new ArrayList();

    static {

        /*

         * Se meten en el array versions las distintas versiones

         * del protocolo en orden descendente

         */

            //versions.add(WMSProtocolHandler1_3_0.class);

        //versions.add(WMSProtocolHandler1_1_1.class);

            supportedVersions.add("1.3.0");

            supportedVersions.add("1.1.1");

            supportedVersions.add("1.1.0");

     }

    /**

     * 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 WMSProtocolHandler negotiate(String host) throws ConnectException, IOException {

        if (supportedVersions.size() == 0)

        {

                return null;

        }

        try

        {

                String highestVersionSupportedByServer  = getSuitableWMSVersion(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 WMS supports and we are able to read.

                        Iterator iVersion = supportedVersions.iterator();

                        String wmsVersion;

                        String gvSIGVersion;

                        while (iVersion.hasNext()) {

                                gvSIGVersion = (String)iVersion.next();

                                wmsVersion = getSuitableWMSVersion(host,gvSIGVersion);

                                //TODO:

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

                                // send GetCapabilities and read the version to compare.

                                int res = wmsVersion.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: " + wmsVersion);

                                } else { //Si es menor que nuestra version

                                         //Obtenemos la primera version menor o igual que tengamos

                                    String lowerVersion = WMSProtocolHandlerFactory.getDriverVersion(wmsVersion, iVersion);

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

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

                                    } else {

                                        if (lowerVersion.equals(wmsVersion)) {

                                            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)

        {

                logger.warn("Can't determine server version",e);

                  return null;

        }

    }

     /**

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

      * if the version parameter is null, the WMS 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 getSuitableWMSVersion(String host, String _version) throws ConnectException, IOException

     {

         int sizes[] = new int[] { 1024, 1024*10, 1024*50, 1024*100 };

         XmlPullParserException  xmlEx = null;

         for( int i=0; i<sizes.length; i++ ) {

             String version;

             try {

                 version = getSuitableWMSVersion(host, _version, sizes[i]);

                 return version;

             } catch (XmlPullParserException ex) {

                 xmlEx = ex;

                 // Try with other size

             }

         }

         logger.warn("Can't determine server version",xmlEx);

         return "";

     }

     private static String getSuitableWMSVersion(String host, String _version, int size) throws ConnectException, IOException, XmlPullParserException

     {

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

            String version = new String();

            StringReader reader = null;

            DataInputStream dis = null;

                try

                {

                        URL url = new URL(request);

            byte[] buffer = new byte[size];

            URLConnection conn = url.openConnection();

            conn.setRequestProperty("Accept", "text/xml, text/*, */*");

            conn.setRequestProperty("User-Agent", "Mozilla/5.0 (gvSIG) like Gecko");

            dis = new DataInputStream(conn.getInputStream());

            dis.read(buffer);

            String string = new String(buffer);

            // patch for ArcIMS + WMS connector > 9.0 bug

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

            if (a !=-1)

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

            // end patch

            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.CAPABILITIES_ROOT1_1_0)==0)

                                    ||(kxmlParser.getName().compareTo(CapabilitiesTags.CAPABILITIES_ROOT1_1_1)==0)

                                    ||(kxmlParser.getName().compareTo(CapabilitiesTags.CAPABILITIES_ROOT1_3_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)

                {

                    throw  xmlEx;

//                    logger.warn("Can't determine server version",xmlEx);

//                    return "";

                }

                finally{

                        if (reader != null)

                        {

                                try{

                                        reader.close();

                                }catch(Exception ex){

                                        logger.warn("Can't close reader",ex);

                                }

                        }

                        if (dis != null)

                        {

                                try {

                                        dis.close();

                                } catch(Exception ex) {

                                        logger.warn("Can't close input stream",ex);

                                }

                        }

                }

     }

     /**

      * It creates an instance of a WMSDriver class.

      *

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

      * @return WMSDriver.

      */

       private static WMSProtocolHandler createVersionDriver(String version)

       {

         try

         {

           Class driver;

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

           driver = Class.forName("org.gvsig.remoteclient.wms.wms_"+version+".WMSProtocolHandler" + version);

           return (WMSProtocolHandler)driver.newInstance();

         }

         catch (Exception e)

         {

                logger.warn("Can't create WMS protocol handler for version '"+version+"'.",e);

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

                 return null;

         }

       }

 }