Hi!
The team I'm working with has been experimenting with Empire DB in a small
Apache Click webapp for managing a Confluence wiki.
Our experience so far with no-strings has been good, but we'd appreciate advice
on how to best use Empire DB persistence patterns.
The webapp has five model objects, persisted to h2 for development / Oracle in
production. Maven, Spring for DI only, liquibase for DB migration,
TestNG/Surefire. We created a PersistenceManager class just like the Spring
example, and injected it with WikiMgtDB (extends DBDatabase), a DataSource, and
the Empire DB Driver. The PM class grew large with get/search/updates for the
business objects, so we created DAO classes for each model object and injected
each with WikiMgtD via Spring.
The PersistenceManager is injected into the Apache Click action classes for the
webapp and can retrieve/store objects, but is not much more than a proxy that
gives each DAO classes a Connection (see example).
PersistenceManagerImpl {
….
public SpaceSummary getSpaceSummary(String serverName, String spaceKey) {
Connection conn = getConnection();
spaceSummaryDAO.setConnection(conn);
SpaceSummary ss = spaceSummaryDAO.getSpaceSummary(serverName, spaceKey);
releaseConnection(conn);
return ss;
}
This pattern seems wrong, and test cases cannot be written against the DAO
objects directly because they don't have a Connection.
(A related puzzle is connection and transaction management which has been
problematic with @Transactional annotations across updates involving more than
one DAO. )
I've looked over most all of the sample code, found a lot of good ideas, but I
need advice on EmpireDB patterns with more than one DAO, patterns for
retrieving nested objects, proper connection management, and also how to best
handle "paged" retrieval of 90,000 records.
Thanks in advance for any/all comments/feedback…and I'm happy to provide more
details and contribute lessons back into more example code. (ex, a sample
Apache Click + Empire DB)
Thanks!
Tim
