I want to use the hibernate filter but I don't know if what I want to do is possible
I have 2 entities :
Message and MessageUser.
A Message has a list of MessageUser.
I want to create a filter so I can do something like :
final Session filteredSession = sessionFactory.openSession();
final Filter filter = filteredSession.enableFilter("userRecipient");
filter.setParameter("userRecipient", myUser);
filter.validate();
final List<Message> userMessages = filteredSession.createQuery("from Message").list();
it returns me only the message where myUser is the recipient ?
is it possible to to and how?
Thanks a lot !
If you are comfortable with Criteria you could create criteria like this
Session hbSession= sessionFactory.openSession();
Criteria criteria = hbSession.createCriteria(Message.class);
criteria.createCriteria("msgUserList","userListAlias");// msgUserList is variable name of users list in Message
criteria.add(Restrictions.eq("userListAlias.user",myUser));//user is variable for User type in msgUserList's class.
List<Message> userMessages = criteria.list();
Have a look at this for reference while creating criteria!
If you only want to use filter then I hope you have configured filter on your User
List
some thing like bellow
By *.hbm.xml
<hibernate-mapping package="com....">
<class name="Message" table="message_table">
....
<list name="msgUserList" inverse="true" cascade="all">
<key column="user_id" />
<one-to-many class="MessageUsers" />
<filter name="userRecipient" condition="user_id =:userParam" />
</list>
</class>
<filter-def name="userRecipient">
<filter-param name="userParam" type="User" />//User is class
</filter-def>
</hibernate-mapping>
Or By annotation
@Entity
@FilterDef(name="userRecipient",
parameters=@ParamDef(name="userParam", type="PAKAGE.User" ))
@Table(name = "message_table", catalog = "your_db")
public class Message{
...
@OneToMany(fetch = FetchType.LAZY, mappedBy = "stock")
@Filter(name = "userRecipient",condition="user = :userParam")
public List<MessageUser> msgUserList;
after this you will be able get your filter working
Filter filter = session.enableFilter("userRecipient");
filter.setParameter("userParam", myUser);
Update
Purpose of Filter
is different than the Criteria
, from my understanding you can say that Filter
is just like a Criteria that is already applied on your class or collection which has on
and off
switch. If your hibernate session has certain filter enabled with it's parameters set than that filter is on
and all queries relating to the class or collection which has this filter specified will always return filtered result as per the condition. This means you don't have to explicitly define it every time and by using getEnabledFilter("filterName")
you can just change that filter's parameters any time.
Example usage of filter can be if you have Movies
table and Actor
table with many-to-many relationship, like Leonardo Dicaprio
can have many movies at the same times A titanic
can have many actors, here when you get Actor
obviously you would want only those movies which this Actor
has performed in, so you can use filter here which is applied on collection of Movies
that is mapped in Actor
class. This way when you get Actor
object say by simple criteria of name and nothing else and access it's Movie
collection by .
operator on Actor
object it will return you only movies which that actor has performed. This also means no matter how you got Actor
object from database when you access Movie
collection of Actor
it will provide you movies that this actor has performed in
Criteria on the other hand you can use when you require result from database with certain conditions which does not need to be replicated rather you don't want it to be replicated later in the hibernate session. Like Actor
lets say Leonardo Dicaprio
containing collection of Movies
that got nominated him in Oscar. This collection will only be populated in Actor
object when gone through certain criteria and will not be available on other Actor
objects which have not being retrieved by this criteria.
I hope you understood basic concept of filter and criteria, and from my understanding of your problem it will be better if you use criteria!