How do you lock a component in a stream?

In RTC 6.0.2 we added a feature that lets you lock streams and components to prevent deliveries to the files in those streams or components. Stream and component locks work in a similar manner to file locks but apply to the entire stream or the entire component in a stream. When a stream or component is locked, any attempted deliveries by users who do not own the lock will fail with an appropriate error message. The user that holds the lock can still perform deliveries to the stream. A lock does not only prevent deliveries, it also prevents any operation that affects the files in the locked component or stream. For example, a component replace is also prevented.

See:
-New & Noteworthy Mention: https://jazz.net/downloads/rational-team-concert/releases/6.0.2?p=newsDetails#stream-locking
-Stream/Component Locking Demo Video: https://www.youtube.com/watch?v=b8QwzwUF2ZY
-SCM Command Line Client 'set lock' command: https://www.ibm.com/support/knowledgecenter/SSCP65_6.0.4/com.ibm.team.scm.doc/topics/set_lock.html

Prior to 6.0.2, you could add a deliver advisor in the process spec to restrict deliveries to particular streams. By protecting your stream by particular roles or users, you can effectively lock the stream down.
"http://jazz.net/library/article/215#protect_some" describes how to protect individual components in a stream, the same approach can be used to lock down the entire stream.

You can't stop people from changing the files in their own workspaces, but you can use a deliver precondition to stop them from delivering a component's changes to a stream. See Use permissions to control delivery to components. One limitation of that precondition is that it must be configured on the process area (project or team) that owns the stream. If you have many teams that own streams where you want to restrict delivery of a component, the precondition must be configured in each team.