Example
To understand the concepts of JTX its best to see an example. To make things simpler, our transactional resource will be a simple String
value. Let's create one such class:
Now we are ready to begin our journey:)
ResourceManager
The first thing is to create a JtxResourceManager
for our resource. The main method to implement is beginTransaction()
. It starts a transaction on our resource depending on transaction mode.
Since we will use JtxTransactionManager
, propagation behavior and timeout will be already supported! Therefore, our resource manager has only to deal with isolation and read-only attribute. We will ignore isolation to make things simpler. Here is how resource manager may look like:
Quick overview of what we have done in beginTransaction()
\: the active
flag tells us if real transaction should be started or we are working in auto-commit mode. When it is set, we create a transaction-aware resource. Since isolation is ignored, we only need to pass read-only flag.
Usage
Now we are ready to use JTX\:
The most important thing to remember is that in step #2 we are just requesting a jtx transaction. Not until the next step, #3, the real transaction will be started. Again, we are requesting a resource, therefore, if we call it several time in a row, the same resource instance will be returned.
Worker
JTX also provides LeanJtxWorker
, a class that utilizes JtxTransactionManager
and makes it more convenient for use when transaction is requested over different context, i.e. with transaction nesting. Basically, everything stays the same, except LeanJtxWorker
would return null
when new transaction is not created on its request, meaning that current transaction matches the requested transaction attributes (mostly propagation).
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