Explicitly updates the {@link #getLastAccessTime() lastAccessTime} of this session to the current time whenthis method is invoked. This method can be used to ensure a session does not time out.
Most programmers won't use this method directly and will instead rely on the last access time to be updated automatically as a result of an incoming web request or remote procedure call/method invocation.
However, this method is particularly useful when supporting rich-client applications such as Java Web Start appp, Java or Flash applets, etc. Although rare, it is possible in a rich-client environment that a user continuously interacts with the client-side application without a server-side method call ever being invoked. If this happens over a long enough period of time, the user's server-side session could time-out. Again, such cases are rare since most rich-clients frequently require server-side method invocations.
In this example though, the user's session might still be considered valid because the user is actively "using" the application, just not communicating with the server. But because no server-side method calls are invoked, there is no way for the server to know if the user is sitting idle or not, so it must assume so to maintain session integrity. This {@code touch()} method could be invoked by the rich-client application code during thosetimes to ensure that the next time a server-side method is invoked, the invocation will not throw an {@link ExpiredSessionException ExpiredSessionException}. In short terms, it could be used periodically to ensure a session does not time out.
How often this rich-client "maintenance" might occur is entirely dependent upon the application and would be based on variables such as session timeout configuration, usage characteristics of the client application, network utilization and application server performance.
@throws InvalidSessionException if this session has stopped or expired prior to calling this method.