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.wfs;

import java.io.File;

import java.io.IOException;

import java.net.ConnectException;

import java.util.ArrayList;

import java.util.Hashtable;

import java.util.Iterator;

import org.gvsig.compat.net.ICancellable;

import org.gvsig.remoteclient.RemoteClient;

import org.gvsig.remoteclient.wfs.exceptions.WFSException;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 * Represents the class the with the necessary logic to connect to a 

 * OGCWFS and interpretate the data 

 * @author Jorge Piera Llodr? (piera_jor@gva.es)

 */

public class WFSClient extends RemoteClient{

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

        private WFSProtocolHandler handler;

        //private Logger LOG = LoggerFactory.getLogger(WFSClient.class);

        /**

         * Constructor.

         * the parameter host, indicates the WFS host to connect.

         * @throws ConnectException,IOException 

         *

         */

        public WFSClient(String host) throws ConnectException,IOException {

                setHost(host);

                handler = WFSProtocolHandlerFactory.negotiate(host);

                handler.setHost(host);  

        }

        public WFSClient(String host, String version) throws IOException {

                setHost(host);

                if (version == null) {

                        try {                

                                handler = WFSProtocolHandlerFactory.negotiate(host);                                  

                        } catch(ConnectException conE) {

                                logger.warn("Can'r negotiate version for the host '"+host+"'.",conE);

                                throw conE; 

                        } catch(IOException ioE) {

                                logger.warn("Can'r negotiate version for the host '"+host+"'.",ioE);

                                throw ioE; 

                        } catch(Exception e) {

                                logger.warn("Can'r negotiate version for the host '"+host+"'.",e);

                        } 

                }else{

                        handler = WFSProtocolHandlerFactory.createVersionDriver(version);

                }

                if (handler == null){

                        logger.warn("Unsupported version '"+version+"' for host '"+host+"'.");

                        throw new UnsupportedOperationException("Unsupported version");

                }

                handler.setHost(host);                        

        }

        /**

         * Every OGC Web Service (OWS), including a Web Feature Service,

         * must have the ability to describe its capabilities by returning

         * service metadata in response to a GetCapabilities request.

         * @param status

         * WFS client status. Contains all the information to create

         * the query

         */

        public void getCapabilities(WFSStatus status, boolean override, ICancellable cancel)throws WFSException {

                handler.getCapabilities(status,override,cancel);                

        }

        /**

         * The function of the DescribeFeatureType operation is to 

         * generate a schema description of feature types serviced 

         * by a WFS implementation. The schema descriptions define 

         * how a WFS implementation expects feature instances to 

         * be encoded on input (via Insert and Update requests) 

         * and how feature instances will be generated on output 

         * (in response to GetFeature and GetGmlObject requests). 

         * @param status

         * WFS client status. Contains all the information to create

         * the query

         */

        public File describeFeatureType(WFSStatus status, boolean override, ICancellable cancel)throws WFSException {

                return handler.describeFeatureType(status,override,cancel);                

        }

        /**

         * The GetFeature operation allows retrieval of features from a 

         * web feature service. A GetFeature request is processed by

         * a WFS and when the value of the outputFormat attribute is 

         * set to text/gml a GML instance document, containing the 

         * result set, is returned to the client.

         * @param status

         * WFS client status. Contains all the information to create

         * the query

         * @return File

         * GML File

         */

        public File getFeature(WFSStatus status, boolean override, ICancellable cancel) throws WFSException{

            if ((status.getNamespaceLocation() != null) && (status.getNamespacePrefix() == null)){

                String namespacePrefix = getServiceInformation().getNamespacePrefix(status.getNamespaceLocation());

                if (namespacePrefix != null){

                    status.setNamespacePrefix(namespacePrefix);

                }

        }

            return handler.getFeature(status,override,cancel);

        }

        /**

         * The Transaction operation is used to describe data transformation 

         * operations that are to be applied to web accessible feature 

         * instances. A web feature service may process a Transaction 

         * operation directly or possibly translate it into the language 

         * of a target datastore to which it is connected and then have the

         * datastore execute the transaction. When the transaction has been 

         * completed, a web feature service will generate an XML response 

         * document indicating the completion status of the transaction.

         * @param status

         * WFS client status. Contains all the information to create

         * the query

         */

        public void transaction(WFSStatus status, boolean override, ICancellable cancel) throws WFSException{

                handler.transaction(status,override,cancel);

        }

        /**

         * Web connections are inherently stateless. As a consequence 

         * of this, the semantics of serializable transactions are not 

         * preserved. To understand the issue, consider an update operation.

         * The client fetches a feature instance. The feature is then 

         * modified on the client side, and submitted back to the database 

         * via a Transaction request for update. Serializability is lost 

         * since there is nothing to guarantee that while the feature was 

         * being modified on the client side, another client did not come 

         * along and update that same feature in the database.

         * One way to ensure serializability is to require that access to

         * data be done in a mutually exclusive manner; that is while one 

         * transaction accesses a data item, no other transaction can modify 

         * the same data item. This can be accomplished by using locks that 

         * control access to the data.

         * The purpose of the LockFeature operation is to expose a long 

         * term feature locking mechanism to ensure consistency. The lock

         * is considered long term because network latency would make 

         * feature locks last relatively longer than native commercial 

         * database locks.

         * The LockFeature operation is optional and does not need to be 

         * implemented for a WFS implementation to conform to this 

         * specification. If a WFS implements the LockFeature operation, 

         * this fact must be advertised in the capabilities document

         * @param status

         */

        public void lockFeature(WFSStatus status, boolean override, ICancellable cancel)throws WFSException {

                handler.lockFeature(status,override,cancel);

        }

        /**

         * <p>Checks the connection to de remote WFS and requests its 

         * capabilities.</p>

         * 

         */

        public boolean connect(boolean override, ICancellable cancel) 

        {

                try {

                        if (handler == null) {

                                if (getHost().trim().length() > 0) {                   

                                        handler = WFSProtocolHandlerFactory.negotiate(getHost());

                                        handler.setHost(getHost());

                                } else {

                                        // must to specify host first!!!!

                                        return false;

                                }

                        }

                        getCapabilities(null,override,cancel);                        

                        return true;

                } catch (Exception e) {

                        logger.warn("Can't connect to host '"+this.hostName+"'.",e);

                        return false;

                }

        }

        /*

         *  (non-Javadoc)

         * @see org.gvsig.remoteClient.RemoteClient#connect(org.gvsig.remoteClient.wms.ICancellable)

         */

        public boolean connect(ICancellable cancel) {

                return connect(false, cancel);

        }

        /*

         *  (non-Javadoc)

         * @see org.gvsig.remoteClient.RemoteClient#close()

         */

        public void close() {

                // TODO Auto-generated method stub

        }

         public String getVersion()

         {

                 return handler.getVersion();

         }         

         /**

     * Gets the Service information included in the Capabilities

     */

    public WFSServiceInformation getServiceInformation(){

        return (WFSServiceInformation)handler.getServiceInformation();  

    }

    /**

     * Returns the features list

     * @return

     */

    public Hashtable getFeatures()

    {

        return handler.getFeatures();  

    }

    public WFSFeature getFeature(String nameSpace, String localName){

        Iterator it = handler.getFeatures().keySet().iterator();

        String fullName = localName;

        String prefix = getServiceInformation().getNamespacePrefix(nameSpace);

        if (prefix != null){

            fullName = prefix + ":" + localName;

        }

        while (it.hasNext()){

            String featureName = (String)it.next();

            if (localName.equals(featureName)){

                return (WFSFeature)handler.getFeatures().get(localName);

            }

            if (fullName.equals(featureName)){

                return (WFSFeature)handler.getFeatures().get(fullName);

            }

        }

        return null;

    }

        /**

         * @return the lastWfsRequestInformation

         */

        public WFSRequestInformation getLastWfsRequestInformation() {

                return handler.getLastWfsRequestInformation();

        }

        /**

         * @return the number requests

         */

        public int getWFSRequestInformationCount(){

                return handler.getWfsRequestInformations().size();

        }

        /**

         * Return the information of a request

         * @param index

         * The position of the request

         * @return

         */

        public WFSRequestInformation getWFSRequestInformationAt(int index){

                ArrayList wfsRequestInformations = handler.getWfsRequestInformations();

                if (index < wfsRequestInformations.size()){

                        return (WFSRequestInformation)wfsRequestInformations.get(index);

                }

                return null;

        }

}