Why does Spring have class JdbcDaoSupport, but no analagous class JmsSupport?

Question

Why does the Spring Framework have class JdbcDaoSupport that requires a DataSource and creates a JdbcTemplate internally, but has no analagous class JmsSupport that might require a JMS ConnectionFactory and create a JmsTemplate?

As I understand, the purpose of class JdbcDaoSupport is to eliminate redundant instances of JdbcTemplate (one per DataSource instance) in an application context. Instead, the container creates instances of an application DAO, each of which derives from JdbcDaoSupport, accepts a unique DataSource and provides this DataSource to the JdbcDaoSupport parent instance which in turn provides it to its internal JmsTemplate.

Why doesn't Spring provide an analogous class JmsSupport that would serve to reduce the number of JmsTemplate instances in an application context?

Answer 1

JdbcDaoSupport is little more than a user of a JdbcTemplate that also extends DaoSupport. It provides a base implementation of the DAO design pattern for JDBC, like other classes do for Hibernate, JPA, and others.

A lot of people don't use the DAO paradigm; instead, they define a singleton JdbcTemplate that they inject directly into their service layer.

For JMS, there is - as far as I know - no generic design pattern like the DAO, and there's no other possible variations on "a user of JmsTemplate". You should use a singleton JmsTemplate: there's nothing more to it.