Spring Batch - Use Cases

Use Cases for Spring Batch

These are more like scenarios or flows than real use cases in formal UML terms, but they serve a useful purpose as both. We don't want to be over formal, and probably code is being written and tested at the same time as these use cases. But there are many stakeholders in this project, and use cases are a useful resource to make sure they are all agreed on scope and certain implementation details.

Simple Batch Repeat
Automatic Retry After Failure
Commit Batch Process Periodically: chunk processing.
Asynchronous Chunk Processing: parallel processing within a chunk.
Copy File to File in a Batch
Massively Parallel Batch Processing. Spring Batch 1.0 does not contain any implementations of this use case, but it is quite feasible to implement them using the framework as a starting point. 1.1 has some prototype code under the Integration module.
Manual Restart After Failure
Sequential Processing of Dependent Steps
Partial Processing: skip records (e.g. on rollback).
Whole-Batch Transaction - transactional support for the whole batch, not just chunks. Quite a common requirement, but not always practical using normal transaction support. May require a staging area, and a decision after it is full about whether to copy it in one big batch (e.g. using native database tools) or chunk it (e.g. if it is now in a form for which chunk failure is easier to deal with).
Scheduled Processing: Batch Jobs controlled by scheduler (e.g. start, stop, suspend, kill). Spring Batch does not intend to implement the scheduler concerns, but needs to provide enough information that a scheduler can act appropriately.
Non-Sequential Processing of Steps (Conditional Branching)
Pause and Resume Job Execution

Actors

The following actors are involved in the use cases (Container and Client being the most common / important).

Client or Business Domain

Code written by the batch developer.

One aim us that the client is a POJO - the batch behaviour, boundary conditions, transactions etc. can be dealt with by the Container in such as way that the client does not need to know about them. The client may have access to framework abstractions, like templated data sources (JdbcTemplate etc.), but these should work the same whether they are in a batch or not.

Container

An application that converts user requests for batch jobs into running processes. Container concerns are robustness, traceability, manageability.

Framework

The Framework is the infrastructure code that the Container depends on, and possibly spi implementations where knowledge of the non-business logic resides.

The Framework provides two kinds of infrastruture (as per usual Spring cornerstones AOP and Portable Service Abstractions):

For cross-cutting concerns there are interceptors that can be wrapped around client code without it needing any knowledge of the Framework at all. An existing parallel is with transaction support - the client code can use TransactionTemplate directly, but does not always need to.
Concrete abstractions that allow access to resources in a uniform way without needing to know the details of how they are provided (e.g. partitioned). Client code can use these abstractions like it would a use a DaoSupport.

Operator

The batch operator is not a developer. Tools are provided for the Operator to be able to stop and start a batch, and to monitor the progress and status of on ongoing or finished batch.

Business User

The Operator has technical skills, e.g. a member of an application support team, but may need help with business-related decisions. For instance if input data are bad, he would not expect to be able to fix them alone because they might be bad for a business reason.

Documentation

Support