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Sometimes you need to write a custom finder for a table that belongs to core. In my case it was JournalArticle.  My client wanted to avoid using the ext-plugin as much as possible so I had to try to figure out a way to do it within a portlet plugin.

I tried to use dynamic queries as a solution but it turned out to be inadequate because I was unable to group by (I wanted to get the latest articles with a certain structureId).

I needed a custom finder but for awhile I thought this was impossible because you needed to load the Impl of a model during the query which is inaccessible since it is part of portal-impl.  But my experimentation with dynamic queries was not in vain because I figured... if dynamic queries can figure out a way to load the impl class I could probably do the same.

So here is the class I wrote.

It consists of two basic methods:

public static Class getImplClass(Class clazz, ClassLoader classLoader) {
    if (!clazz.getName().endsWith("Impl")) {
        String implClassName = clazz.getPackage().getName() + ".impl." + 
            clazz.getSimpleName() + "Impl";

       	clazz = _classMap.get(implClassName);

       	if (clazz == null) {    
            try {
               			if (classLoader == null) {   
                    Thread currentThread = Thread.currentThread();

                    classLoader = currentThread.getContextClassLoader(); 
                }

                clazz = classLoader.loadClass(implClassName); 
               _classMap.put(implClassName, clazz); 
            }
            catch (Exception e) {
                _log.error("Unable find model " + implClassName, e);
            }
        } 
    }
    return clazz;
}
	
public static Session openPortalSession() throws ORMException {
    return sessionFactory.openSession();	
}

private static Log _log = LogFactoryUtil.getLog(CustomFinderHelperUtil.class);

private static Map> _classMap = new HashMap>();
	
private static SessionFactory sessionFactory =
    (SessionFactory)PortalBeanLocatorUtil.locate("liferaySessionFactory");

So basically in my customFinder instead of doing

session = openSession();

I did

session = CustomFinderHelperUtil.openPortalSession();

and instead of doing

q.addEntity("JournalArticle",  JournalArticleImpl.class));

I did

q.addEntity("JournalArticle", CustomFinderHelperUtil.getImplClass(
                JournalArticle.class, true));

(I created a extra method that took a boolean to use the portalClassLoader, you can load it using PortalClassLoaderUtil.getPortalClassLoader())

Hopefully this helps some you guys out.