[ http://issues.apache.org/jira/browse/IBATIS-246?page=comments#action_12367082 ]
Sven Boden commented on IBATIS-246: ----------------------------------- As originally requested by Stephane Bailliez in IBATIS-161: "Following my post in the dev list. It would probably be interesting to have fine-grained control over the lazy-loading. For instance, having a per-statement lazy-loading flag where dependent requests (like in the case of n+1 selects) would inherit this flag. I came over it after discovering that cglib-enhanced classes are not serializable, which make sense due to lazy-loading. You could need it for the following case: You may know, that your relationships are not in the form 1:bazillion but more like 1:4 (replace 4 by your favorite 'less than 10' number) with very lightweights objects , thus the need to potentially be able to disable cglib enhanced relations. To workaround this, you can: 1) disable application-wide lazy loading via <settings/> (big side-effect) 2) implements your own serialization mechanism by basically cloning the relations. (code clutter) " > Lazy Load per Result > -------------------- > > Key: IBATIS-246 > URL: http://issues.apache.org/jira/browse/IBATIS-246 > Project: iBatis for Java > Type: New Feature > Components: SQL Maps > Versions: 2.1.5, 2.1.6 > Environment: Any > Reporter: S Boyd > > I have a need for LazyLoad on a per result basis. Since I saw this feature > listed in the wish list for 2.1.5, I attempted to add it to this version's > source. The lazy load global setting should be the default setting assigned > for all results in the sqlmaps. If this is not desired for a particular > result, then it can be overrided by the lazyLoad="true|false" on the affected > result. In adding this feature, I had to modify the sqlmap dtd and three > java classes: SqlMapParser, BasicResultMap, and BasicResultMapping. > In the SqlMapParser, I retrieved the lazy load property from the result > element at the beginning of the code block. If the lazyLoad property is not > specified in the result, then the global setting is used. This logic is > inserted on line 416. > Lines: 407-414 > 407: BasicResultMapping mapping = new BasicResultMapping(); > /* code omitted here */ > 414: mapping.setNestedResultMapName(resultMapName); > > if(lazyLoad != null && lazyLoad.length() > 0){ > mapping.setLazyLoad("true".equals(lazyLoad)); > } > else{ // use global lazy load setting > > mapping.setLazyLoad(vars.client.getDelegate().isLazyLoadingEnabled()); > } > In the BasicResultMap, I temporarily override the global lazy load setting > with the BasicResultMapping's lazyload value. The reason for this was to > avoid changing the ResultLoader.loadResult signature. Maybe this can be > improved upon. > Line 442 was modifed to this: > /* Set global lazy load setting to mapping's lazy load */ > boolean globalLazyLoad = client.isLazyLoadingEnabled(); > > client.getDelegate().setLazyLoadingEnabled(mapping.isLazyLoad()); > > result = ResultLoader.loadResult(client, statementName, > parameterObject, targetType); > > /* Reset global lazy load to original value */ > client.getDelegate().setLazyLoadingEnabled(globalLazyLoad); > In the BasicResultMapping, I simply added a new property (lazyLoad:boolean) > with set/getters. > Please let me know if this can be reviewed/refined and possibly added to the > next release. Or if you want the modifed java files and dtd. > Regards, > Stephen -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
