[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2463) ClassCastException when Hibernate tries to cache results using ResultTransformer

[Jaco Greyling (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-2463?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_29516 ] 

Jaco Greyling commented on HHH-2463:
------------------------------------

I have exactly the same problem. I'm however using another transformer (e.g. Transformers.aliasToBean(Entry.class)) but same effect. Any news on this?

> ClassCastException when Hibernate tries to cache results using ResultTransformer
> --------------------------------------------------------------------------------
>
>                 Key: HHH-2463
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2463
>             Project: Hibernate3
>          Issue Type: Bug
>    Affects Versions: 3.2.2
>            Reporter: Peak user
>
> When Hibernate executes a cacheable query using a ResultTransformer, it will attempt to cache the results AFTER applying the ResultTransformer. The problem is that the ResultTransformer may modify the data in a way that Hibernate won't understand it anymore, and in this case it will generate a ClassCastException when trying to cache it.
> This problem could be easily solved if Hibernate cached results before applying the ResultTransformer instead of afterwards.
> Here's a sample code to reproduce this problem:
> class ToMapResultTransformer implements ResultTransformer {
>     private String[] properties;
>     public ToMapResultTransformer(String[] properties) {
>         this.properties = properties;
>     }
>     public List transformList(List collection) {
>         return collection;
>     }
>     public Object transformTuple(Object[] tuple, String[] aliases) {
>         Map<String,Object> result = new HashMap<String,Object>(tuple.length);
>         for (int i=0; i<tuple.length; i++) {
>             result.put((properties != null ? properties[i] : aliases[i]), tuple[i]);
>         }
>         return result;
>     }
> }
> Criteria sqlCriteria = createSqlCriteria(session);
> sqlCriteria.setProjection(projections);
> sqlCriteria.setCacheable(true);
> sqlCriteria.setResultTransformer(new ToMapResultTransformer(properties));
> sqlCriteria.list();
> The code above produces the following exception:
> java.lang.ClassCastException: java.util.HashMap
> 	at org.hibernate.cache.StandardQueryCache.put(StandardQueryCache.java:83)
> 	at org.hibernate.loader.Loader.putResultInQueryCache(Loader.java:2185)
> 	at org.hibernate.loader.Loader.listUsingQueryCache(Loader.java:2129)
> 	at org.hibernate.loader.Loader.list(Loader.java:2087)
> 	at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
> 	at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569)
> 	at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)

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