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 Summary

Fields
Modifier and Type	Field	Description
`static int`	`FLUSH_CASCADE_SYNC`	A synchronization type that results in changes from an ObjectContext to be recorded in the parent DataChannel.
`static int`	`FLUSH_NOCASCADE_SYNC`	A synchronization type that results in changes from an ObjectContext to be recorded in the parent DataChannel.
`static EventSubject`	`GRAPH_CHANGED_SUBJECT`
`static EventSubject`	`GRAPH_FLUSHED_SUBJECT`
`static EventSubject`	`GRAPH_ROLLEDBACK_SUBJECT`
`static int`	`ROLLBACK_CASCADE_SYNC`	A synchronization type that results in cascading rollback of changes through the DataChannel stack.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`EntityResolver`	`getEntityResolver()`	Returns an EntityResolver instance that contains runtime mapping information.
`EventManager`	`getEventManager()`	Returns an EventManager associated with this channel.
`QueryResponse`	`onQuery(ObjectContext originatingContext, Query query)`	Executes a query, using provided context to register persistent objects if query returns any objects.
`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.

- Field Detail
  - 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:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - 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 Detail
  - 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.

Interface DataChannel

Field Summary

Method Summary

Field Detail

FLUSH_NOCASCADE_SYNC

FLUSH_CASCADE_SYNC

ROLLBACK_CASCADE_SYNC

GRAPH_CHANGED_SUBJECT

GRAPH_FLUSHED_SUBJECT

GRAPH_ROLLEDBACK_SUBJECT

Method Detail

getEventManager

getEntityResolver

onQuery

onSync