How to you convert these lines of self servicing code internal AppEntity _AppEntity = null;

if ( !_AppEntity.FetchUsingUCAppName( appName, prefetch ) {

}

to Adapter Model since Adapter model does not have AppEntityBase which contains .FetchUsingUCAppName

_AppEntity.AppName = appName; then, you can call

adapter.FetchEntityUsingUniqueConstraint(_AppEntity, _AppEntity.ConstructFilterForUCAppName(), prefetch);

to fetch the entity