org.mortbay.cometd
Class AbstractCometdServlet

java.lang.Object
  extended by javax.servlet.GenericServlet
      extended by 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


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