Package org.apache.cayenne
Interface DataChannel
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- 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
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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.
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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.
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Field Detail
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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
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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
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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
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GRAPH_CHANGED_SUBJECT
static final EventSubject GRAPH_CHANGED_SUBJECT
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GRAPH_FLUSHED_SUBJECT
static final EventSubject GRAPH_FLUSHED_SUBJECT
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GRAPH_ROLLEDBACK_SUBJECT
static final EventSubject GRAPH_ROLLEDBACK_SUBJECT
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Method Detail
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getEventManager
EventManager getEventManager()
Returns an EventManager associated with this channel. Channel may return null if EventManager is not available for any reason.
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getEntityResolver
EntityResolver getEntityResolver()
Returns an EntityResolver instance that contains runtime mapping information.
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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.
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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 ofFLUSH_NOCASCADE_SYNC
,FLUSH_CASCADE_SYNC
,ROLLBACK_CASCADE_SYNC
.
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