org.opendaylight.mdsal.common.api

Interface AsyncDataBroker<P extends org.opendaylight.yangtools.concepts.Path<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

All Known Implementing Classes:

AbstractDOMDataBroker, BindingDOMDataBrokerAdapter, ForwardingDOMDataBroker, SerializedDOMDataBroker

public interface AsyncDataBroker<P extends org.opendaylight.yangtools.concepts.Path<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()

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 and AsyncWriteTransaction.submit().

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.

Method Summary

Methods

Modifier and Type	Method and Description
AsyncReadTransaction<P,D>	newReadOnlyTransaction() Allocates a new read-only transaction which provides an immutable snapshot of the data tree.
AsyncWriteTransaction<P,D>	newWriteOnlyTransaction() Allocates new write-only transaction based on latest state of data tree.

Method Detail

newReadOnlyTransaction

AsyncReadTransaction<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

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.submit() 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.submit().

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