Hi Christian, I understand your point but I don't get its relation to my question at all. Continuing your example, I would ask why employee.getName() will prematurely load the boss. A priori, I would expect the proxy to be smarter and only trigger the loading of boss if getBoss() was effectively called.
Regards -- Bardamu On Wed, Dec 16, 2009 at 3:09 PM, Poitras Christian <christian.poit...@ircm.qc.ca> wrote: > Hi, > > The major problem that was present in iBATIS 2 was that lazy loaded class > where not always of the right type. > For exemple, if I have multiple subclasses of a class. > Person > Employee inherits Person > Director inherits Employee > > If I have an object Employee with a method getBoss() that returns an Employee > (lazy loaded), I expect that sometimes it will be a director. > In iBATIS 2, testing (employee.getBoss() instanceof Director) will always be > false. This problem is due to the fact that iBATIS does not know the real > class of the boss property and creates a Proxy of Employee. > In iBATIS 3, testing (employee.getBoss() instanceof Director) will be true if > the employee's boss is a Director. To know the real type, the statement must > be executed. > > Christian > > > -----Original Message----- > From: Carlos Pita [mailto:carlosjosep...@gmail.com] > Sent: Wednesday, December 16, 2009 11:45 AM > To: user-java@ibatis.apache.org > Subject: Lazy loading differences between ibatis 2 and 3 > > Hi all, > > I've the following sqlmap for ibatis 2. Suppose ibatis has its lazy-loading > feature enabled and I obtain a user U by means of findUserById. Then I call > U.getEmail() and findMemberById is not executed. That's fine, one wouldn't > expect the associated member to be loaded until there is a real need for it. > Of course, if then I call > U.getMember().getDescription() findMemberById does execute its select, in due > time. That said, for ibatis 3 the same example executes findMemberById as > soon as U.getEmail() is invoked, loading the member before time. That's not > surprising if one inspects the code of ResultObjectProxy (relevant parts > copied below). Is this intended to work the way it does or is it a bug? > > <sqlMap namespace="User"> > > <resultMap id="userMap" class="User"> > <result property="email" column="email"/> > <result property="member" column="member_id" select="findMemberById"/> > </resultMap> > > <resultMap id="memberMap" class="Member"> > <result property="description" column="description"/> > </resultMap> > > <select id="findUserById" resultMap="userMap"> > select * from qpoint_user where id = #id# > </select> > > <select id="findMemberById" resultMap="memberMap"> > select * from cpp_member where member_id = #id# > </select> > > </sqlMap> > > > public class ResultObjectProxy { > > public Object invoke(Object o, Method method, Object[] args) throws > Throwable { > try { > if (!Object.class.equals(method.getDeclaringClass()) && > PropertyNamer.isGetter(method.getName())) { > lazyLoader.loadAll(); <-- this loads all asociations for every > getter invoked on this proxy > } > return method.invoke(target, args); > } catch (Throwable t) { > throw ExceptionUtil.unwrapThrowable(t); > } > } > } > > Regards > -- > Bardamu > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-java-unsubscr...@ibatis.apache.org > For additional commands, e-mail: user-java-h...@ibatis.apache.org > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-java-unsubscr...@ibatis.apache.org > For additional commands, e-mail: user-java-h...@ibatis.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: user-java-unsubscr...@ibatis.apache.org For additional commands, e-mail: user-java-h...@ibatis.apache.org
