Package org.apache.cayenne

Interface DataChannel

All Known Subinterfaces:
ObjectContext
All Known Implementing Classes:
BaseContext, ClientChannel, ClientServerChannel, DataContext, DataDomain
public interface DataChannel
DataChannel is an abstraction used by ObjectContexts to obtain mapping metadata and access a persistent store. There is rarely a need to use it directly.
Since:
1.2

  • Field Details

    • FLUSH_NOCASCADE_SYNC

      static final int FLUSH_NOCASCADE_SYNC
      A synchronization type that results in changes from an ObjectContext to be recorded in the parent DataChannel. If the parent is itself an ObjectContext, changes are NOT propagated any further.
      See Also:

    • FLUSH_CASCADE_SYNC

      static final int FLUSH_CASCADE_SYNC
      A synchronization type that results in changes from an ObjectContext to be recorded in the parent DataChannel. If the parent is itself an ObjectContext, it is expected to send its own sync message to its parent DataChannel to cascade synchronization all the way down the stack.
      See Also:

    • ROLLBACK_CASCADE_SYNC

      static final int ROLLBACK_CASCADE_SYNC
      A synchronization type that results in cascading rollback of changes through the DataChannel stack.
      See Also:

    • GRAPH_CHANGED_SUBJECT

      static final EventSubject GRAPH_CHANGED_SUBJECT

    • GRAPH_FLUSHED_SUBJECT

      static final EventSubject GRAPH_FLUSHED_SUBJECT

    • GRAPH_ROLLEDBACK_SUBJECT

      static final EventSubject GRAPH_ROLLEDBACK_SUBJECT

  • Method Details

    • getEventManager

      EventManager getEventManager()
      Returns an EventManager associated with this channel. Channel may return null if EventManager is not available for any reason.

    • getEntityResolver

      EntityResolver getEntityResolver()
      Returns an EntityResolver instance that contains runtime mapping information.

    • onQuery

      QueryResponse onQuery(ObjectContext originatingContext, Query query)
      Executes a query, using provided context to register persistent objects if query returns any objects.
      Parameters:
      originatingContext - an ObjectContext that originated the query, used to register result objects.
      Returns:
      a generic response object that encapsulates result of the execution.

    • onSync

      GraphDiff onSync(ObjectContext originatingContext, GraphDiff changes, int syncType)
      Processes synchronization request from a child ObjectContext, returning a GraphDiff that describes changes to objects made on the receiving end as a result of synchronization.
      Parameters:
      originatingContext - an ObjectContext that initiated the sync. Can be null.
      changes - diff from the context that initiated the sync.
      syncType - One of FLUSH_NOCASCADE_SYNC, FLUSH_CASCADE_SYNC, ROLLBACK_CASCADE_SYNC.