Hibernate and Spring - Beginning Hibernate: From Novice to Professional - page 305

Table C-1. The Core HibernateTemplate Methods

Method Description

bulkUpdate()

Performs a bulk update or delete on the database, according to the provided
HQL query and entities

contains()

Determines whether the given object exists as an entity in the database

delete() Deletes an entity from the database

find()

Carries out an HQL query

get() Obtains an entity by its id (primary key)

persist()

Saves an entity to the database

refresh() Refreshes an entity from the database

save()

Saves an entity to the database

saveOrUpdate()

Saves an entity to the database or updates it as appropriate

update()

Updates an entity in the database

When a more complex set of operations is required than can be achieved in a single line,
the execute() method is used to invoke an instance of HibernateCallback . Our example appli-
cation uses HibernateCallback to implement its createArticle() method. This is shown in
Listing C-10.

Listing C-10. Invoking a HibernateCallback Object from the Template's execute() Method

public Paper createArticle(final Integer paperId,final Article article) {
HibernateCallback callback = new HibernateCallback() {
public Object doInHibernate(Session session) {
Paper paper = (Paper)session.get(Paper.class,paperId);
paper.addArticle(article);
session.update(paper);
return paper;

}

};
return (Paper)getHibernateTemplate().execute(callback);

}

Although this allows us to invoke more complex code from the HibernateTemplate class,
and HibernateTemplate obviates the need for specific management of the session, it doesn't
make the implementation particularly terse, and probably makes it slightly harder to under-
stand. Listing C-11 shows how the same method can be implemented without using
HibernateTemplate .