Support lightweight transactions (if [not] exists) [DATACASS-250]

[spring-projects-issues]

Anton Koscejev opened DATACASS-250 and commented

It would be nice to support lightweight transactions. At least in CassandraOperations, so that they can be used by custom repository methods.

Something like this:

<T> boolean insertIfNotExists(T entity);
<T> boolean updateIfExists(T entity);

Or this (note the exceptions):

<T> T insertIfNotExists(T entity) throws CassandraEntityExistsException;
<T> T updateIfExists(T entity) throws CassandraEntityDoesNotExistException;

Or perhaps simply adding it to WriteOptions:

public IfOption getIfOption() {
     return ifOption;
}
public void setIfOption(IfOption ifOption) {
     this.ifOption = ifOption;
}

With some Enum like this:

public enum IfOption {IF_EXISTS, IF_NOT_EXISTS}

Or as two separate options (but then have to ensure only one is specified).

With insert/update automatically chosen based on which option is specified, if any. And exceptions thrown in case of WriteOptions

---

Referenced from: pull request #107, and commits 8d64401, b72ad3d, 10eab88, 6ccab0f

[spring-projects-issues]

Antoine Toulme commented

Here is a long way to do it:
Insert insert = CassandraTemplate.createInsertQuery(cassandratemplate.getTableName(user.getClass()).toCql(), entity, options, cassandraTemplate.getConverter());
insert.ifNotExists()
cassandraTemplate.execute(insert);

I think this could be repurposed into a method of CassandraTemplate easily

[spring-projects-issues]

John Blum commented

Reviewed, polished and merged! Thank you!