Re: [castor-dev] Lazy loading with long transaction

[Denis Sukhoroslov]

Hi Dmitry,   thanks for the answer. Unfortunatelly i cannot use your suggestion - in that case all objects in the collection will be loaded from database. The result will be the same if i will not use lazy="true" at all :).  Another solution for that - to implement my own RelationCollection and copy in a setter method all ids from Castor RelationCollection to it. Now i m thinking about not to close the transaction on the first stage, but i afraid about deadlocks :(.   Denis. ----- Original Message ----- From: Dmitry Vereshchagin To: [EMAIL PROTECTED] Sent: Friday, December 06, 2002 2:13 PM Subject: Re: [castor-dev] Lazy loading with long transaction Hi Denis, I faced the same problem. Apparently it's implementation feature: transaction closing invalidates result set. The workaround is to copy all the elements from castor collection into your own collection explicitly while transaction is open.       db.begin();     master = (Master)db.load(...); //  copying code here //  ...............     db.commit();     db.close()   Avoid transaction timeouts on large collections ))   regards   Dmitry Vereshchagin ----- Original Message ----- From: Denis Sukhoroslov To: [EMAIL PROTECTED] Sent: Wednesday, December 04, 2002 3:58 PM Subject: [castor-dev] Lazy loading with long transaction Hi folks,   does anyone managed to use a lazy loading feature with long transactions? I do have a biderectional 1:N relationship between Master and Detail objects. My mapping file is:     <class name="Master" identity="id" access="shared" key-generator="IDENTITY">     ...     <field name="details" type="Detail" lazy="true" collection="collection">       <sql many-key="MasterID" />     </field>   </class>   <class name="Detail" identity="id" key-generator="IDENTITY">     ...     <field name="master" type="Master" >       <sql name="MasterID" />     </field>   </class> i'm loading a master object in short transaction and close it just after master object was loaded, so master.getDetails method will give me a RelationCollection with only detail identities loaded.     ...     db.begin();     master = (Master)db.load(...);     db.commit();     db.close()     ...     Collection list = master.getDetails();     Iterator itr = list.iterator();     while (itr.hasNext()) {       Object o = itr.next();   // <--- this line gets an error       System.out.println(o);     }   And, when i trying to go through the details collection it gives me an error: "Transaction is closed!": java.lang.RuntimeException: Transaction is closed!  at org.exolab.castor.persist.RelationCollection$IteratorImp.lazyLoad(Unknown Source)  at org.exolab.castor.persist.RelationCollection$IteratorImp.next(Unknown Source)   ...   Any ideas how to avoid that problem?   Thanks, Denis.