I have a component which should always produce the output by executing a code and not from the dispatcher cache.
Is there any way to clear the dispatcher cache for the component or is it possible to disable the component caching.
The dispatcher caches the entire HTTP response body, so doing what you are describing actually requires two steps:
1) Loading the non-cacheable component through Ajax (or some other edge side assembly technology like ESI)
2) Including the Dispatcher: no-cache header in the response when that component is requested.
#1 is pretty easy to do with jQuery
#2 is covered here: http://dev.day.com/content/kb/home/Dispatcher/faq-s/DispatcherNoCache.html
You will probably want to use the WCMMode to only do the dynamic loading on the publish server.
Another way to make sure the dispatcher does not cache that ajax request for the component snippet is to add a query parameter, for example: /content/site/my/page/jcr:content/par/component.html?cachekiller=1245
The dispatcher will not cache any requests with a query part.