org.sapia.ubik.rmi.server.transport.http.servlet

Class ServletTransportProvider

java.lang.Object

org.sapia.ubik.rmi.server.transport.http.servlet.ServletTransportProvider

All Implemented Interfaces:

ServletConsts, TransportProvider

public class ServletTransportProvider
extends Object
implements TransportProvider, ServletConsts

This transport provider is intended to be instantiated from within a servlet. The servlet delegates request handling to this instance's handleRequest() method.

The code excerpt below demonstrates how to create an instance of this class and use it in a servlet implementation:

 ...

 public void init(ServletConfig conf) throws ServletException {
   _provider = new ServletTransportProvider();
    TransportManager.registerProvider(_provider);

   Properties props = new Properties();

   // property below would normally be passed through a
   // servlet init parameter.

   props.setProperty(ServletConsts.SERVLET_URL_KEY,
                     "http://localhost:8080/ubik");

  // this tells ubik "under" which transport our object will be exported
   props.setProperty(Consts.TRANSPORT_TYPE, ServletConsts.DEFAULT_SERVLET_TRANSPORT_TYPE);

   try{
     _foo = new UbikFoo();
     Hub.exportObject(_foo, props);
   }catch(RemoteException e){
    throw new ServletException("Could not export Foo", e);
   }
 }

 ...

 protected void service(HttpServletRequest req, HttpServletResponse res)
   throws ServletException, IOException {
   _provider.handleRequest(req, res);
 }

 ...
 

Then, in a client VM, to connect to the remote object, we proceed as follows:

 TransportManager.registerProvider(new ServletTransportProvider());
 Foo foo = (Foo)Hub.connect(new ServletAddress("http://localhost:8080/ubik"));
 

NOTE: there can be only ONE instance of this instance registered to the Hub per web application

.

Author:

Yanick Duchesne

See Also:

handleRequest(HttpServletRequest, HttpServletResponse)

Field Summary

Fields inherited from interface org.sapia.ubik.rmi.server.transport.http.servlet.ServletConsts

DEFAULT_SERVLET_TRANSPORT_TYPE, SERVLET_URL_KEY

Constructor Summary

Constructors

Modifier	Constructor and Description
	ServletTransportProvider()
protected	ServletTransportProvider(String transportType)

Method Summary

Methods

Modifier and Type	Method and Description
Connections	getPoolFor(ServerAddress address) Returns a client connection pool to the given server address.
String	getTransportType() Returns this instance's "transport type".
void	handleRequest(javax.servlet.http.HttpServletRequest httpReq, javax.servlet.http.HttpServletResponse httpRes)
Server	newDefaultServer() This method is called by Ubik RMI's runtime when a server is needed on the client side to recieve asynchronous responses (i.e.: callbacks).
Server	newServer(Properties props) This method returns a Server impl., given the properties passed in.
void	shutdown() Empty implementation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ServletTransportProvider

public ServletTransportProvider()

ServletTransportProvider

protected ServletTransportProvider(String transportType)

Method Detail

getTransportType

public String getTransportType()

Description copied from interface: TransportProvider

Returns this instance's "transport type".

Specified by:

getTransportType in interface TransportProvider

Returns:

a transport type.

See Also:

TransportProvider.getTransportType()

newDefaultServer

public Server newDefaultServer()
                        throws RemoteException

Description copied from interface: TransportProvider

This method is called by Ubik RMI's runtime when a server is needed on the client side to recieve asynchronous responses (i.e.: callbacks). Implementations must in this case provide a "default" Server instance.

Specified by:

newDefaultServer in interface TransportProvider

Returns:

a Server.

Throws:

RemoteException

See Also:

TransportProvider.newDefaultServer()

newServer

public Server newServer(Properties props)
                 throws RemoteException

This method returns a Server impl., given the properties passed in. A single property is expected: ubik.rmi.transport.servlet.url, whose value must correspond to the URL of the servlet that is encapsulating this instance.

Specified by:

newServer in interface TransportProvider

Parameters:

props - the Properties used to create the server.

Returns:

a Server instance.

Throws:

RemoteException

See Also:

ServletConsts.SERVLET_URL_KEY, TransportProvider.newServer(java.util.Properties)

shutdown

public void shutdown()

Empty implementation.

Specified by:

shutdown in interface TransportProvider

See Also:

TransportProvider.shutdown()

getPoolFor

public Connections getPoolFor(ServerAddress address)
                       throws RemoteException

Description copied from interface: TransportProvider

Returns a client connection pool to the given server address.

Specified by:

getPoolFor in interface TransportProvider

Parameters:

address - a ServerAddress.

Returns:

a ConnectionOptionsException.

Throws:

RemoteException - if a problem occurs creating the connection.

See Also:

TransportProvider.getPoolFor(org.sapia.ubik.net.ServerAddress)

handleRequest

public void handleRequest(javax.servlet.http.HttpServletRequest httpReq,
                 javax.servlet.http.HttpServletResponse httpRes)