httpjndiinitialcontextfactory.java

实现了Jms的服务器源码,支持多种适配器,DB,FTP,支持多种数据库

/**
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright
 *    statements and notices.  Redistributions must also contain a
 *    copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the
 *    above copyright notice, this list of conditions and the
 *    following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. The name "Exolab" must not be used to endorse or promote
 *    products derived from this Software without prior written
 *    permission of Exoffice Technologies.  For written permission,
 *    please contact [e-mail].
 *
 * 4. Products derived from this Software may not be called "Exolab"
 *    nor may "Exolab" appear in their names without prior written
 *    permission of Exoffice Technologies. Exolab is a registered
 *    trademark of Exoffice Technologies.
 *
 * 5. Due credit should be given to the Exolab Project
 *    (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2001-2004 (C) Exoffice Technologies Inc. All Rights Reserved.
 *
 * $Id: HttpJndiInitialContextFactory.java,v 1.20 2004/01/29 12:14:14 tanderson Exp $
 */
package org.exolab.jms.jndi.http;

import java.util.Hashtable;

import javax.naming.ConfigurationException;
import javax.naming.Context;
import javax.naming.NameParser;
import javax.naming.NamingException;
import javax.naming.ServiceUnavailableException;
import javax.naming.spi.InitialContextFactory;

import org.apache.avalon.excalibur.naming.DefaultNamespace;
import org.apache.avalon.excalibur.naming.RemoteContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.exolab.core.http.HttpClient;
import org.exolab.core.util.URI;
import org.exolab.jms.jndi.JndiConstants;


/**
 * This is the client side helper class that retrieves the root context
 * of the JNDI server. This class implements the InitialContextFactory
 * interface.
 *
 * @version     $Revision: 1.20 $ $Date: 2004/01/29 12:14:14 $
 * @author      <a href="mailto:[e-mail]">Jim Mourikis</a>
 * @author      <a href="mailto:[e-mail]">Tim Anderson</a>
 */
public class HttpJndiInitialContextFactory implements InitialContextFactory {

    /**
     * The JNDI servlet name
     */
    protected static final String SERVLET = "openjms/OpenJMSJndi";

    /**
     * The allowed scheme names for the provider URL
     */
    private static final String HTTP_SCHEME = "http";

    /**
     * The logger
     */
    private static final Log _log =
        LogFactory.getLog(HttpJndiInitialContextFactory.class);


    /**
     * Default constructor
     */
    public HttpJndiInitialContextFactory() {
    }

    /**
     * Creates an initial context for beginning name resolution.
     *
     * @param environment the environment specifying information to be used in
     * the creation of the initial context.
     * @return the initial context
     * @throws NamingException if the initial context cannot be created
     */
    public Context getInitialContext(Hashtable environment)
        throws NamingException {
        Context context = null;
        String url = getProviderURL(environment);

        HttpClient connection = openConnection(url);
        NameServiceProxy provider = new NameServiceProxy(connection);
        NameParser parser;
        try {
            parser = provider.getNameParser();
        } catch (NamingException exception) {
            throw exception;
        } catch (Exception exception) {
            NamingException error = new ServiceUnavailableException(
                exception.getMessage());
            error.setRootCause(exception);
            throw error;
        }
        DefaultNamespace namespace = new DefaultNamespace(parser);
        Hashtable env = new Hashtable(environment);
        env.put(RemoteContext.NAMING_PROVIDER, provider);
        env.put(RemoteContext.NAMESPACE, namespace);
        return new RemoteContext(env, parser.parse(""));
    }

    /**
     * Returns the JNDI provider URL
     *
     * @return the JNDI provider URL
     * @throws NamingException if the URL cannot be determined
     */
    protected String getProviderURL(Hashtable environment)
        throws NamingException {

        if (environment == null) {
            throw new ConfigurationException(
                "Cannot connect to JNDI provider - environment not set");
        }
        String url = (String) environment.get(Context.PROVIDER_URL);
        if (url != null) {
            URI uri;
            try {
                uri = new URI(url);
            } catch (URI.MalformedURIException exception) {
                throw new ConfigurationException(
                    "Malformed JNDI provider URL: " + url);
            }
            if (!HTTP_SCHEME.equals(uri.getScheme())) {
                throw new ConfigurationException(
                    "URL=" + url + " has an invalid scheme");
            }
            String path = uri.getPath();
            if (path == null || path.length() == 0) {
                url += "/" + SERVLET;
            } else if (path.equals("/")) {
                url += SERVLET;
            }
        } else {
            url = getDeprecatedEnvironment(environment);
        }

        return url;
    }

    /**
     * Get a connection to the JNDI provider
     *
     * @param url the JNDI provider URL
     * @return a connection to the JNDI provider
     * @throws NamingException if a connection cannot be established
     */
    protected HttpClient openConnection(String url) throws NamingException {
        HttpClient client;
        try {
            client = new HttpClient(url, "HttpJndiInitialContextFactory");
        } catch (Exception exception) {
            NamingException error = new NamingException(
                "Failed to connect to JNDI provider");
            error.setRootCause(exception);
            throw error;
        }
        return client;
    }

    /**
     * Returns the http url using the old environment properties, logging a
     * warning. This method will be removed in future releases
     */
    private String getDeprecatedEnvironment(Hashtable environment) {
        _log.warn(getClass().getName() +
            ": using deprecated environment. Use Context.PROVIDER_URL");

        StringBuffer url = new StringBuffer(HTTP_SCHEME);
        String host = (String) environment.get(JndiConstants.HOST_PROPERTY);
        Integer port = (Integer) environment.get(
            JndiConstants.PORT_NUMBER_PROPERTY);

        // if the host is specified then use it, otherwise use localhost
        if (host != null) {
            url.append(host);
        } else {
            url.append("localhost");
        }

        // if the port has been specified then use it
        if (port != null) {
            url.append(":");
            url.append(port.toString());
        }

        url.append("/");
        url.append(SERVLET);

        return url.toString();
    }

} //-- HttpJndiInitialContextFactory