I have a requirement to integrate alfrecso share with a different repository.The repository can be any ECM other than alfresco whereas the frontend remains same as alfresco. Is this something possible? What are the aspects need to look at for achieving this ? Please provide me the idea how to go for it ?
This seems to be quite difficult and, mainly, a lot of work! Alfresco Share communicates with Alfresco Explorer thanks to web scripts (that is to say HTTP requests on a "REST" API). If you want to keep Alfresco Share and work with another repository, you'll have to develop a similar REST API on your other ECM. Moreover, I don't think that the functionality of this new ECM matches perfectly the functionalities of Alfresco. So, you'll also probably have to customise Alfresco Share.
I think that's possible but I really don't recommend that. You can replace each core service of Alfresco by a custom service that will act like a wrapper to the other ECM. But it doesn't seem to be simpler in my opinion.
Perhaps the best solution is to develop a custom UI similar to Alfresco Share but completely adapted to your ECM.
If you have multiple repositories that support webdav (Alfresco supports webdav) then you can connect them all using Unifyle.
Unifyle (https://www.unifyle.co) helps brings together all document repositories (File shares, Alfresco, Sharepoint, Box, Dropbox, etc.,) in a single dashboard from which you can search, manage, edit and share files easily.