/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is the Kowari Metadata Store.
*
* The Initial Developer of the Original Code is Plugged In Software Pty
* Ltd (http://www.pisoftware.com, mailto:info@pisoftware.com). Portions
* created by Plugged In Software Pty Ltd are Copyright (C) 2001,2002
* Plugged In Software Pty Ltd. All Rights Reserved.
*
* Contributor(s): N/A.
*
* [NOTE: The text of this Exhibit A may differ slightly from the text
* of the notices in the Source Code files of the Original Code. You
* should use the text of this Exhibit A rather than the text found in the
* Original Code Source Code for Your Modifications.]
*
*/
package org.mulgara.server.driver;
// Java 2 Standard Packages
import java.net.*;
import java.util.*;
import javax.naming.*;
// Third party packages
/*
import javax.jmdns.JmDNS; // ZeroConf
import javax.jmdns.ServiceListener;
import javax.jmdns.ServiceInfo;
*/
import org.apache.log4j.Logger; // Apache Log4J
// Locally written packages
import org.mulgara.server.*;
import org.mulgara.util.Reflect;
/**
* Obtain a {@link SessionFactory} instance.
*
* @created 2004-03-30
*
* @author <a href="http://staff.pisoftware.com/raboczi">Simon Raboczi</a>
*
* @version $Revision: 1.9 $
*
* @modified $Date: 2005/01/07 05:43:51 $
*
* @maintenanceAuthor $Author: newmana $
*
* @company <A href="mailto:info@PIsoftware.com">Plugged In Software</A>
*
* @copyright © 2004 <A href="http://www.PIsoftware.com/">Plugged In
* Software Pty Ltd</A>
*
* @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
*/
public abstract class SessionFactoryFinder {
/** Logger. This is named after the class. */
private static final Logger logger = Logger.getLogger(SessionFactoryFinder.class.getName());
/* A ZeroConf peer. This listens for servers on the LAN. */
// private static JmDNS jmdns;
/**
* Map from a database's URI scheme to the name of a {@link SessionFactory}
* implementation for it.
*/
private static final Map<String,String> schemeMap = new HashMap<String,String>();
/**
* Environment setup for setting up a context for the naming registry.
*/
private static final Hashtable<String,String> localContextEnv = new Hashtable<String,String>();
static {
schemeMap.put("beep", "org.mulgara.server.beep.BEEPSessionFactory");
schemeMap.put("rmi", "org.mulgara.server.rmi.RmiSessionFactory");
schemeMap.put("local", "org.mulgara.server.local.LocalSessionFactory");
localContextEnv.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");
localContextEnv.put(Context.PROVIDER_URL, "rmi://localhost");
// try {
// jmdns = new JmDNS(InetAddress.getLocalHost());
// jmdns.addServiceListener("_itql._tcp.local", new ServerServiceListener());
// } catch (Exception e) {
// logger.warn("Couldn't start ZeroConf peer", e);
// }
}
/**
* Obtain a {@link SessionFactory} instance. Assumes that this is being used
* locally - within the same JVM.
*
* @param serverURI the internet server to connect this session to; if
* <code>null</code>, try to find an RMI server named <q>server1</q> on the
* local host
* @throws SessionFactoryFinderException if a connection can't be established
* to the server
*/
public static SessionFactory newSessionFactory(URI serverURI) throws
SessionFactoryFinderException, NonRemoteSessionException {
return newSessionFactory(serverURI, false);
}
/**
* Obtain a {@link SessionFactory} instance.
*
* @param serverURI the internet server to connect this session to; if
* <code>null</code>, try to find an RMI server named <q>server1</q> on the
* local host
* @param isRemote true if the client is trying to connect to a remote server.
* @throws SessionFactoryFinderException if a connection can't be established
* to the server
*/
public static SessionFactory newSessionFactory(URI serverURI,
boolean isRemote) throws SessionFactoryFinderException, NonRemoteSessionException {
// If no serverURI was specified, search the LAN for a local server
if (serverURI == null) serverURI = findServerURI();
assert serverURI != null;
String scheme = serverURI.getScheme();
// Obtain the classname for the SessionFactory
String className;
// Handle RMI schemes differently.
if (scheme.equals("rmi")) {
logger.debug("Attempting to connect via RMI");
// First attempt to connect via RMI.
try {
Hashtable<String,String> environment = new Hashtable<String,String>();
environment.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");
environment.put(Context.PROVIDER_URL, "rmi://" + serverURI.getRawAuthority());
Context rmiRegistryContext = new InitialContext(environment);
rmiRegistryContext.lookup(serverURI.getPath().substring(1));
// If the lookup is successful connect using RMI.
className = (String)schemeMap.get(scheme);
} catch (NamingException ne) {
if (logger.isDebugEnabled()) {
logger.debug("Failed to connect via RMI", ne);
}
// If there is an exception connect locally.
if (!isRemote) {
if (logger.isDebugEnabled()) {
logger.debug("Attempting to fallback to local", ne);
}
className = (String)schemeMap.get("local");
} else {
throw new SessionFactoryFinderException("Cannot find server " + serverURI, ne);
}
}
} else {
className = (String)schemeMap.get(scheme);
}
if (className == null) {
throw new SessionFactoryFinderException(serverURI + " has unsupported scheme (" + scheme + ")");
}
assert className != null;
// Use reflection to create the SessionFactory
try {
return (SessionFactory)Reflect.newInstance(Class.forName(className), serverURI);
} catch (RuntimeException ie) {
Throwable originalEx = ie.getCause();
// check if the exception thrown indicates we should retry
Throwable e = originalEx.getCause();
if (!(e instanceof NonRemoteSessionException)) {
throw new SessionFactoryFinderException("Couldn't create session factory for " + serverURI + " (" + e.getMessage() + ")", e);
}
// tell the calling code
throw (NonRemoteSessionException)originalEx;
} catch (Exception e) {
throw new SessionFactoryFinderException("Couldn't create session factory for " + serverURI, e);
}
}
/**
* Find a server.
*
* This currently only tries for a Java RMI server on the local host.
* Consider falling back to other hosts seen when asking for a session factory.
*
* @return a Java RMI server {@link URI} for the local host, never <code>null</code>
* @throws SessionFactoryFinderException if the server URI can't be composed
*/
public static URI findServerURI() throws SessionFactoryFinderException {
// Look for an RMI server named "server1" on the local host
try {
return new URI(
"rmi", // Java RMI protocol
InetAddress.getLocalHost().getCanonicalHostName(), // host
"/" + getServiceName(),
null // no fragment means this is a server, not a model
);
} catch (UnknownHostException e) {
throw new SessionFactoryFinderException("Couldn't determine local host name", e);
} catch (URISyntaxException e) {
throw new SessionFactoryFinderException("Invalid local server URI", e);
}
}
/**
* Lookup the local registry for any registered names.
* @return The first name registered with the local RMI server, or the default name if this cannot be found.
*/
private static String getServiceName() {
try {
Context rmiRegistryContext = new InitialContext(localContextEnv);
// get the list of names for the default context
NamingEnumeration<NameClassPair> ne = rmiRegistryContext.list(rmiRegistryContext.getNameInNamespace());
// return the first name
if (ne.hasMore()) return ne.next().getName();
} catch (NamingException e) { /* fall back to the default */ }
// error or no name found, so return the default name.
return SessionFactoryFactory.DEFAULT_SERVER_NAME;
}
/**
* Listens for notification via ZeroConf of servers appearing on the LAN.
*/
/*
static class ServerServiceListener implements ServiceListener
{
public void addService(JmDNS jmdns, String type, String name)
{
logger.info("ZeroConf added "+type+" "+name);
}
public void removeService(JmDNS jmdns, String type, String name)
{
logger.info("ZeroConf removed "+type+" "+name);
}
public void resolveService(JmDNS jmdns, String type, String name,
ServiceInfo serviceInfo)
{
logger.info("ZeroConf resolved "+type+" "+name+" to "+serviceInfo);
}
}
*/
}