DataContextFactory needs the ability to decorate an existing
DataContext (like setting user properties or delegate) without needing
to create a DataContext from scratch.
Right now it takes some really ugly code like this because the
lowest-level createDataContext() method checks for a
DataContextFactory. See last section for an example.
I think it would be better to refactor this to provide a method
signature like below, and if dataContextFactory is null, then use the
default cayenne data context.
public DataContext createDataContext(DataContextFactory
dataContextFactory, boolean useSharedCache)
That would allow a DataContextFactory to simply call:
DataDomain dataDomain = (DataDomain)dataChannel;
DataContext dataContext = dataDomain.createDataContext(null,
dataDomain.isSharedCacheEnabled());
It'd be nice to make this more transparent, but I don't know if that's
reasonable.
DataDomain dataDomain = (DataDomain)dataChannel;
DataContext dataContext = dataDomain.createDefaultDataContext();
=================================================================
Example DataContextFactory:
public DataContext createDataContext(DataDomain dataDomain) {
// for new dataRowStores use the same name for all stores
// it makes it easier to track the event subject
DataRowStore snapshotCache = (dataDomain.isSharedCacheEnabled())
? dataDomain.getSharedSnapshotCache()
: new DataRowStore(dataDomain.getName(),
dataDomain.getProperties(), dataDomain.getEventManager());
DataContext context;
context = new DataContext((DataChannel) this, new
ObjectStore(snapshotCache));
context.setValidatingObjectsOnCommit(dataDomain.isValidatingObjectsOnCommit());
return context;
}
public DataContext createDataContext(DataChannel dataChannel,
ObjectStore objectStore)
{
DataContext dataContext = createDataContext((DataDomain)dataChannel);
dataContext.setDelegate(new AuditLoggingDataContextDelegate());
return dataContext;
}
