October 2003
Beginner
734 pages
16h 56m
English
Content preview from Head First EJB
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What does it mean to suspend a transaction?
If a transaction is in progress when a method on a BMT bean is called, the transaction is suspended. Temporarily. The transaction just sits there waiting for the BMT bean to complete its work. Work that’s not part of the caller’s original transaction. Once the BMT method finishes and is popped off the stack, the original transaction kicks back in, right where it left off.
Imagine this scenario: a CMT bean, bean one, is running a method foo() in a transaction (tx A) when it calls a method bar() on bean two (a BMT bean). Once bar() completes and pops off the stack, method foo() invokes another method, bee(), but this time the called bean is another CMT bean (bean three).
When a transaction is suspended, it waits until it can pick up where it left off. But this means that the things that happen while the transaction is suspended are NOT part of the same atomic unit. In other words, the things that happen while the transaction is suspended won’t be rolled back if the suspended transaction (after it comes back to life) fails to commit.
Method foo() of a CMT bean is running in transaction A. Method foo() then invokes method bar() on a BMT bean.
Method bar() suspends transaction A, and starts a new transaction, B. Method bar() runs in the new transaction ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.