org.opendaylight.controller.md.sal.common.api.data

Interface AsyncDataBroker<P extends org.opendaylight.yangtools.concepts.Path<P>,D,L extends AsyncDataChangeListener<P,D>>

Type Parameters:

P - Type of path (subtree identifier), which represents location in tree

D - Type of data (payload), which represents data payload

All Superinterfaces:

AsyncDataTransactionFactory<P,D>

All Known Subinterfaces:

DataBroker, DOMDataBroker, TracingDOMDataBroker

All Known Implementing Classes:

AbstractDOMDataBroker, BindingDOMDataBrokerAdapter, ConcurrentDOMDataBroker, DOMDataBrokerProxy, ForwardingDataBroker, ForwardingDOMDataBroker, LegacyShardedDOMDataBrokerAdapter, PingPongDataBroker, SerializedDOMDataBroker, TracingBroker

public interface AsyncDataBroker<P extends org.opendaylight.yangtools.concepts.Path<P>,D,L extends AsyncDataChangeListener<P,D>>
extends AsyncDataTransactionFactory<P,D>

Base interface that provides access to a conceptual data tree store and also provides the ability to subscribe for changes to data under a given branch of the tree.

All operations on the data tree are performed via one of the transactions:

• Read-Only - allocated using newReadOnlyTransaction()
• Write-Only - allocated using newWriteOnlyTransaction()
• Read-Write - allocated using newReadWriteTransaction()

These transactions provide a stable isolated view of data tree, which is guaranteed to be not affected by other concurrent transactions, until transaction is committed.

For a detailed explanation of how transaction are isolated and how transaction-local changes are committed to global data tree, see AsyncReadTransaction, AsyncWriteTransaction, AsyncReadWriteTransaction and AsyncWriteTransaction.commit().

It is strongly recommended to use the type of transaction, which provides only the minimal capabilities you need. This allows for optimizations at the data broker / data store level. For example, implementations may optimize the transaction for reading if they know ahead of time that you only need to read data - such as not keeping additional meta-data, which may be required for write transactions.

Implementation Note: This interface is not intended to be implemented by users of MD-SAL, but only to be consumed by them.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	AsyncDataBroker.DataChangeScope Scope of Data Change

Method Summary

Modifier and Type	Method and Description
AsyncReadOnlyTransaction<P,D>	newReadOnlyTransaction() Allocates a new read-only transaction which provides an immutable snapshot of the data tree.
AsyncReadWriteTransaction<P,D>	newReadWriteTransaction() Allocates new read-write transaction which provides a mutable view of the data tree.
AsyncWriteTransaction<P,D>	newWriteOnlyTransaction() Allocates new write-only transaction based on latest state of data tree.
org.opendaylight.yangtools.concepts.ListenerRegistration<L>	registerDataChangeListener(LogicalDatastoreType store, P path, L listener, AsyncDataBroker.DataChangeScope triggeringScope) Registers a AsyncDataChangeListener to receive notifications when data changes under a given path in the conceptual data tree.

Method Detail

newReadOnlyTransaction

AsyncReadOnlyTransaction<P,D> newReadOnlyTransaction()

Allocates a new read-only transaction which provides an immutable snapshot of the data tree.

The view of data tree is an immutable snapshot of current data tree state when transaction was allocated.

Specified by:

newReadOnlyTransaction in interface AsyncDataTransactionFactory<P extends org.opendaylight.yangtools.concepts.Path<P>,D>

Returns:

new read-only transaction

newReadWriteTransaction

AsyncReadWriteTransaction<P,D> newReadWriteTransaction()

Allocates new read-write transaction which provides a mutable view of the data tree.

Preconditions for mutation of data tree are captured from the snapshot of data tree state, when the transaction is allocated. If data was changed during transaction in an incompatible way then the commit of this transaction will fail. See AsyncWriteTransaction.commit() for more details about conflicting and not-conflicting changes and failure scenarios.

Specified by:

newReadWriteTransaction in interface AsyncDataTransactionFactory<P extends org.opendaylight.yangtools.concepts.Path<P>,D>

Returns:

new read-write transaction

newWriteOnlyTransaction

AsyncWriteTransaction<P,D> newWriteOnlyTransaction()

Allocates new write-only transaction based on latest state of data tree.

Preconditions for mutation of data tree are captured from the snapshot of data tree state, when the transaction is allocated. If data was changed during transaction in an incompatible way then the commit of this transaction will fail. See AsyncWriteTransaction.commit() for more details about conflicting and not-conflicting changes and failure scenarios.

Since this transaction does not provide a view of the data it SHOULD BE used only by callers which are exclusive writers (exporters of data) to the subtree they modify. This prevents optimistic lock failures as described in AsyncWriteTransaction.commit().

Exclusivity of writers to particular subtree SHOULD BE enforced by external locking mechanism.

Specified by:

newWriteOnlyTransaction in interface AsyncDataTransactionFactory<P extends org.opendaylight.yangtools.concepts.Path<P>,D>

Returns:

new write-only transaction

registerDataChangeListener

org.opendaylight.yangtools.concepts.ListenerRegistration<L> registerDataChangeListener(LogicalDatastoreType store,
                                                                                       P path,
                                                                                       L listener,
                                                                                       AsyncDataBroker.DataChangeScope triggeringScope)

Registers a AsyncDataChangeListener to receive notifications when data changes under a given path in the conceptual data tree.

You are able to register for notifications for any node or subtree which can be reached via the supplied path.

If path type P allows it, you may specify paths up to the leaf nodes then it is possible to listen on leaf nodes.

You are able to register for data change notifications for a subtree even if it does not exist. You will receive notification once that node is created.

If there is any preexisting data in data tree on path for which you are registering, you will receive initial data change event, which will contain all preexisting data, marked as created.

You are also able to specify the scope of the changes you want to be notified.

Supported scopes are:

• AsyncDataBroker.DataChangeScope.BASE - notification events will only be triggered when a node referenced by path is created, removed or replaced.
• AsyncDataBroker.DataChangeScope.ONE - notifications events will only be triggered when a node referenced by path is created, removed or replaced, or any or any of its immediate children are created, updated or removed.
• AsyncDataBroker.DataChangeScope.SUBTREE - notification events will be triggered when a node referenced by the path is created, removed or replaced or any of the children in its subtree are created, removed or replaced.

See AsyncDataBroker.DataChangeScope for examples.

This method returns a ListenerRegistration object. To "unregister" your listener for changes call the "close" method on this returned object.

You MUST call close when you no longer need to receive notifications (such as during shutdown or for example if your bundle is shutting down).

Parameters:

store - Logical Data Store - Logical Datastore you want to listen for changes in. For example LogicalDatastoreType.OPERATIONAL or LogicalDatastoreType.CONFIGURATION

path - Path (subtree identifier) on which client listener will be invoked.

listener - Instance of listener which should be invoked on

triggeringScope - Scope of change which triggers callback.

Returns:

Listener registration object, which may be used to unregister your listener using ListenerRegistration.close() to stop delivery of change events.