How a custom component is called when we install a custom component in UCM.

Question

How a custom component is called when we install a custom component in UCM.
On what event the component services will be activated and called.
Suppose i create a Custom service name MULTIPLECHECKIN then this service will be called on what event and where it will be defined to call.

Answer 1

Saurabh,
the code is packed in the component (see component\Security Filter\java\Security Filter\ModifyAttributesFilter.java - the first Security Filter is the component name, the other Security Filter is the Java package name).
What is important:
- your class must implement the FilterImplementor interface (you will need UCM standard classes - server.zip in your classpath) and its doFilter method
How the filter is executed?
- actually, in this case you don't need any new service - you can use the standard 'hook', which is provided by standard checkin services
- in Component Wizard create a new component, add your compiled class to it (make sure you follow the rules not to end up in classpath issues)
- in Component Wizard click the 'Java Code' tab. Here you can add a Custom filter called validateCheckinData, which is executed by standard checkin services. If you parametrize the filter to call your class created above, you are done.
'Working with Content Components' manual (e.g. here: http://download.oracle.com/docs/cd/E10316_01/cs/cs_doc_10/documentation/developer/using_components_10en.pdf) can give you a basic picture. A better resource is Bex Huff's book - I would recommend you to get it, because it has a step-by-step HelloWorld example which can guide you through Component Wizard. I could also send you my own component (send me an email at [email protected]) which implements a filter for user quotas, so you just need to "replace classes".
As for the other half of your task, searching for the file in the database server will work only if you use database as your storage (ie. install and configure File Store Provider component accordingly). Of course, you could do a search for file in this case - just consider that you will be comparing two BLOBs rather than two relatively short check-sums (most likely strings or arrays of bytes). Besides, it will not work if you use filesystem as your storage.
Jiri