org.gss_project.gss.server.BaseServlet.java Source code

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Here is the source code for org.gss_project.gss.server.BaseServlet.java

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/*
 * 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 org.gss_project.gss.server;

import static org.gss_project.gss.server.configuration.GSSConfigurationFactory.getConfiguration;
import org.gss_project.gss.common.exceptions.RpcException;
import org.gss_project.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");
    }
}