org.mortbay.cometd
Class AbstractCometdServlet

java.lang.Object
  javax.servlet.GenericServlet
      org.mortbay.cometd.AbstractCometdServlet

All Implemented Interfaces:

java.io.Serializable, Servlet, ServletConfig

Direct Known Subclasses:

ContinuationCometdServlet

public abstract class AbstractCometdServlet
extends GenericServlet

Cometd Filter Servlet implementing the AbstractBayeux protocol. The Servlet can be initialized with a json file mapping channels to DataFilter definitions. The servlet init parameter "filters" should point to a webapplication resource containing a JSON array of filter definitions. For example:

  [
    { 
      "channels": "/**",
      "class"   : "org.mortbay.cometd.filter.NoMarkupFilter",
      "init"    : {}
    }
  ]
 

The following init parameters can be used to configure the servlet:

timeout

The server side poll timeout in milliseconds (default 250000). This is how long the server will hold a reconnect request before responding.

interval

The client side poll timeout in milliseconds (default 0). How long a client will wait between reconnects

maxInterval

The max client side poll timeout in milliseconds (default 30000). A client will be removed if a connection is not received in this time.

multiFrameInterval

the client side poll timeout if multiple connections are detected from the same browser (default 1500).

JSONCommented

If "true" then the server will accept JSON wrapped in a comment and will generate JSON wrapped in a comment. This is a defence against Ajax Hijacking.

filters

the location of a JSON file describing DataFilter instances to be installed

requestAvailable

If true, the current request is made available via the AbstractBayeux.getCurrentRequest() method

loglevel

0=none, 1=info, 2=debug

directDeliver

true if published messages are delivered directly to subscribers (default). If false, a message copy is created with only supported fields (default true).

refsThreshold

The number of message refs at which the a single message response will be cached instead of being generated for every client delivered to. Done to optimize a single message being sent to multiple clients.

Author:

gregw, aabeling: added JSONP transport

See Also:

AbstractBayeux}, ChannelId}, Serialized Form

Field Summary

static int	__DEFAULT_REFS_THRESHOLD
protected AbstractBayeux	_bayeux
protected int	_refsThreshold
static java.lang.String	BROWSER_ID
static java.lang.String	CLIENT_ATTR
static java.lang.String	HTTP_CLIENT_ID
static java.lang.String	MESSAGE_PARAM
static java.lang.String	TRANSPORT_ATTR
static java.lang.String	TUNNEL_INIT_PARAM

Constructor Summary

AbstractCometdServlet()

Method Summary

protected java.lang.String	browserId(HttpServletRequest request)
AbstractBayeux	getBayeux()
protected org.cometd.Message[]	getMessages(HttpServletRequest request)
void	init() A convenience method which can be overridden so that there's no need to call super.init(config).
protected abstract AbstractBayeux	newBayeux()
protected java.lang.String	newBrowserId(HttpServletRequest request, HttpServletResponse response)
protected abstract void	service(HttpServletRequest req, HttpServletResponse resp)
void	service(ServletRequest req, ServletResponse resp) Called by the servlet container to allow the servlet to respond to a request.

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

CLIENT_ATTR

public static final java.lang.String CLIENT_ATTR

See Also:

Constant Field Values

TRANSPORT_ATTR

public static final java.lang.String TRANSPORT_ATTR

See Also:

Constant Field Values

MESSAGE_PARAM

public static final java.lang.String MESSAGE_PARAM

See Also:

Constant Field Values

TUNNEL_INIT_PARAM

public static final java.lang.String TUNNEL_INIT_PARAM

See Also:

Constant Field Values

HTTP_CLIENT_ID

public static final java.lang.String HTTP_CLIENT_ID

See Also:

Constant Field Values

BROWSER_ID

public static final java.lang.String BROWSER_ID

See Also:

Constant Field Values

_bayeux

protected AbstractBayeux _bayeux

__DEFAULT_REFS_THRESHOLD

public static final int __DEFAULT_REFS_THRESHOLD

See Also:

Constant Field Values

_refsThreshold

protected int _refsThreshold

Constructor Detail

AbstractCometdServlet

public AbstractCometdServlet()

Method Detail

getBayeux

public AbstractBayeux getBayeux()

newBayeux

protected abstract AbstractBayeux newBayeux()

init

public void init()
          throws ServletException

Description copied from class: GenericServlet

A convenience method which can be overridden so that there's no need to call super.init(config).

Instead of overriding GenericServlet.init(ServletConfig), simply override this method and it will be called by GenericServlet.init(ServletConfig config). The ServletConfig object can still be retrieved via GenericServlet.getServletConfig().

Overrides:

init in class GenericServlet

Throws:

ServletException - if an exception occurs that interrupts the servlet's normal operation

service

protected abstract void service(HttpServletRequest req,
                                HttpServletResponse resp)
                         throws ServletException,
                                java.io.IOException

Throws:

ServletException

java.io.IOException

service

public void service(ServletRequest req,
                    ServletResponse resp)
             throws ServletException,
                    java.io.IOException

Description copied from class: GenericServlet

Called by the servlet container to allow the servlet to respond to a request. See Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse).

This method is declared abstract so subclasses, such as HttpServlet, must override it.

Specified by:

service in interface Servlet

Specified by:

service in class GenericServlet

Parameters:

req - the ServletRequest object that contains the client's request

resp - the ServletResponse object that will contain the servlet's response

Throws:

ServletException - if an exception occurs that interferes with the servlet's normal operation occurred

java.io.IOException - if an input or output exception occurs

browserId

protected java.lang.String browserId(HttpServletRequest request)

newBrowserId

protected java.lang.String newBrowserId(HttpServletRequest request,
                                        HttpServletResponse response)

getMessages

protected org.cometd.Message[] getMessages(HttpServletRequest request)
                                    throws java.io.IOException

Throws:

java.io.IOException