Synnefo

/*

 * Copyright 2008, 2009, 2010 Electronic Business Systems Ltd.

 *

 * This file is part of GSS.

 *

 * GSS 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.

 *

 * GSS 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 GSS.  If not, see <http://www.gnu.org/licenses/>.

 */

package gr.ebs.gss.server;

import static gr.ebs.gss.server.configuration.GSSConfigurationFactory.getConfiguration;

import gr.ebs.gss.client.exceptions.RpcException;

import gr.ebs.gss.server.ejb.ExternalAPI;

import java.io.UnsupportedEncodingException;

import java.net.URLEncoder;

import java.util.Formatter;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.rmi.PortableRemoteObject;

import javax.servlet.http.HttpServlet;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

/**

 * The base servlet contains a collection of helper methods.

 *

 * @author past

 */

public class BaseServlet extends HttpServlet {

        /**

         * The request parameter name for the GWT code server URL, used when

         * debugging.

         */

        protected static final String GWT_SERVER_PARAM = "gwt.codesvr";

        /**

         * The serial version UID of the class.

         */

        private static final long serialVersionUID = 1L;

        /**

         * The logger.

         */

        private static Log logger = LogFactory.getLog(BaseServlet.class);

        /**

         * A helper method that retrieves a reference to the ExternalAPI bean and

         * stores it for future use.

         *

         * @return an ExternalAPI instance

         * @throws RpcException in case an error occurs

         */

        protected ExternalAPI getService() throws RpcException {

                try {

                        final Context ctx = new InitialContext();

                        final Object ref = ctx.lookup(getConfiguration().getString("externalApiPath"));

                        return (ExternalAPI) PortableRemoteObject.narrow(ref, ExternalAPI.class);

                } catch (final NamingException e) {

                        logger.error("Unable to retrieve the ExternalAPI EJB", e);

                        throw new RpcException("An error occurred while contacting the naming service");

                }

        }

        /**

         * Return the name of the service.

         */

        protected String getServiceName() {

                return getConfiguration().getString("serviceName", "GSS");

        }

        /**

         * Decode the request attribute provided by the container to a UTF-8

         * string, since GSS assumes all data to be encoded in UTF-8. The

         * servlet container's encoding can be specified in gss.properties.

         */

        protected String decodeAttribute(Object attribute) throws UnsupportedEncodingException {

                return new String(attribute.toString().getBytes(getConfiguration().getString("requestAttributeEncoding")), "UTF-8");

        }

        /**

         * A helper method that converts a byte buffer to a printable list of

         * hexadecimal numbers.

         */

        protected String getHexString(byte[] buffer) {

                StringBuilder sb = new StringBuilder();

                Formatter formatter = new Formatter(sb);

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

                        formatter.format("0x%x, ", buffer[i]);

                return sb.toString();

        }

        protected String encode(String parameter) throws UnsupportedEncodingException {

                return URLEncoder.encode(parameter, "UTF-8");

        }

}