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copied!<p>What do you mean by MDB? MessageDrivenBean? If the answer if yes - what do you mean by reading from MDB multiple times? Since MDBs are message-driven, we can't read from them at any time, so basis on my understanding of your question I'd do it in the following way:</p> <ol> <li>MDB receives message and stores received entry in some DB table - that would be some kind of transition table; such tables are often used during processing of financial transactions</li> <li>Batch window comes - job is triggered.</li> <li>Now you can query the table in any way you want. Since you are looking for splitting and processing the data concurrently, I'd advice using <a href="http://static.springsource.org/spring-batch/reference/html/scalability.html#partitioning" rel="nofollow">Spring Batch partitioning</a> with <code>TaskExecutorPartitionHandler</code> executing step locally in concurrent threads. What you need to do is to read data from database differentiating on combination of column values - that should be relatively easy - it's just a matter of constructing appropriate SQL query.</li> <li>Processed chunks are aggregated into <code>ItemWriter write(List<? extends T> items)</code> depending on commit interval; if such aggregation is not enough for you, I'd add another table and Batch step that aggregates previously processed entries.</li> </ol> <p>Basically that's how batch processing works - you read items, transforms them and write. The next step - if it's not just a simple tasklet - does exactly the same.</p>

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