com.boylesoftware.cb2.bcmproviders.http
Class HttpBCMProvider

java.lang.Object
  com.boylesoftware.cb2.bcmproviders.http.HttpBCMProvider

All Implemented Interfaces:

BroadcastMessagingProvider

public final class HttpBCMProvider

extends java.lang.Object

implements BroadcastMessagingProvider

Implementation of the BroadcastMessagingProvider interface which uses HTTP to deliver messages to the members of the cluster.

This provider implementation requires a special servlet deployed on every member of the cluster. The servlet is implemented by ReceiverServlet class and can be deployed in the web.xml file as follows:

 ...

 <servlet>
   <servlet-name>bcmreceiver</servlet-name>
   <display-name>The CB2 BCM Receiver</display-name>
   <servlet-class>com.boylesoftware.cb2.bcmproviders.http.ReceiverServlet</servlet-class>
   <load-on-startup>12</load-on-startup>
 </servlet>

 ...

 <servlet-mapping>
   <servlet-name>bcmreceiver</servlet-name>
   <url-pattern>/cb2-bcm</url-pattern>
 </servlet-mapping>

 ...

It is not necessary to protect the receiver servlet's URL, because it always checks that the request comes with the same password specified by com.boylesoftware.cb2.broadcastMessaging.http.password application property. This also means that this property has to have the same value on all the cluster members. The password is passed as a request parameter and is clear text though, so for better security you may consider protecting the URL restricting access, for example, only to the cluster members' IP addresses.

This implementation uses the following application parameters:

• com.boylesoftware.cb2.broadcastMessaging.http.password - password, which is used to protect internal cluster communication. This password must be the same on all cluster members.
• com.boylesoftware.cb2.broadcastMessaging.http.xxx.url - URL of bmcreceiver servlet of a cluster member. The xxx is the member's name, which can be any string. Specify one such property for each member of the cluster including the local member itself (so the set of properties is exactly the same on all cluster members).

Version:

$Id: HttpBCMProvider.java,v 1.5 2004/04/08 18:32:23 levahim Exp $

Author:

Lev Himmelfarb

Field Summary

Fields inherited from interface com.boylesoftware.cb2.BroadcastMessagingProvider

LOG_SUBSYS

Constructor Summary

HttpBCMProvider()

Method Summary

void	broadcastMessage(java.lang.String channelName, java.io.Serializable messageParam) Send a message to all cluster members.
void	destroy() Destroy the provider.
void	init(ApplicationContext appCtx) Initialize the provider instance.

Methods inherited from class java.lang.Object

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

Constructor Detail

HttpBCMProvider

public HttpBCMProvider()

Method Detail

init

public void init(ApplicationContext appCtx)
          throws ApplicationException

Initialize the provider instance.

Specified by:

init in interface BroadcastMessagingProvider

Parameters:

appCtx - the application context.

Throws:

ApplicationException - if a serious error has happened and the provider cannot be initialized.

destroy

public void destroy()

Destroy the provider.

Specified by:

destroy in interface BroadcastMessagingProvider

broadcastMessage

public void broadcastMessage(java.lang.String channelName,
                             java.io.Serializable messageParam)

Send a message to all cluster members.

Specified by:

broadcastMessage in interface BroadcastMessagingProvider

Parameters:

channelName - logical name of the channel, to which the message is targeted.

messageParam - optional message parameter, may be null.