org.opendaylight.controller.md.sal.binding.api

Interface ReadTransaction

All Superinterfaces:

AsyncReadTransaction<org.opendaylight.yangtools.yang.binding.InstanceIdentifier<?>,org.opendaylight.yangtools.yang.binding.DataObject>, AsyncTransaction<org.opendaylight.yangtools.yang.binding.InstanceIdentifier<?>,org.opendaylight.yangtools.yang.binding.DataObject>, org.opendaylight.yangtools.concepts.Identifiable<Object>

All Known Subinterfaces:

ReadOnlyTransaction, ReadWriteTransaction

All Known Implementing Classes:

ForwardingReadOnlyTransaction, ForwardingReadWriteTransaction

public interface ReadTransaction
extends AsyncReadTransaction<org.opendaylight.yangtools.yang.binding.InstanceIdentifier<?>,org.opendaylight.yangtools.yang.binding.DataObject>

A transaction that provides read access to a logical data store.

For more information on usage and examples, please see the documentation in AsyncReadTransaction.

Method Summary

Modifier and Type	Method and Description
default com.google.common.util.concurrent.CheckedFuture<Boolean,ReadFailedException>	exists(LogicalDatastoreType store, org.opendaylight.yangtools.yang.binding.InstanceIdentifier<?> path) Checks if data is available in the logical data store located at provided path.
<T extends org.opendaylight.yangtools.yang.binding.DataObject> com.google.common.util.concurrent.CheckedFuture<com.google.common.base.Optional<T>,ReadFailedException>	read(LogicalDatastoreType store, org.opendaylight.yangtools.yang.binding.InstanceIdentifier<T> path) Reads data from the provided logical data store located at the provided path.

Methods inherited from interface org.opendaylight.controller.md.sal.common.api.data.AsyncTransaction

getIdentifier

Method Detail

read

<T extends org.opendaylight.yangtools.yang.binding.DataObject> com.google.common.util.concurrent.CheckedFuture<com.google.common.base.Optional<T>,ReadFailedException> read(LogicalDatastoreType store,
                                                                                                                                                                            org.opendaylight.yangtools.yang.binding.InstanceIdentifier<T> path)

Reads data from the provided logical data store located at the provided path.

If the target is a subtree, then the whole subtree is read (and will be accessible from the returned data object).

Parameters:

store - Logical data store from which read should occur.

path - Path which uniquely identifies subtree which client want to read

Returns:

a CheckFuture containing the result of the read. The Future blocks until the commit operation is complete. Once complete:

• If the data at the supplied path exists, the Future returns an Optional object containing the data.
• If the data at the supplied path does not exist, the Future returns Optional#absent().
• If the read of the data fails, the Future will fail with a ReadFailedException or an exception derived from ReadFailedException.

exists

default com.google.common.util.concurrent.CheckedFuture<Boolean,ReadFailedException> exists(LogicalDatastoreType store,
                                                                                            org.opendaylight.yangtools.yang.binding.InstanceIdentifier<?> path)

Checks if data is available in the logical data store located at provided path.

Note: a successful result from this method makes no guarantee that a subsequent call to read(org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType, org.opendaylight.yangtools.yang.binding.InstanceIdentifier<T>) will succeed. It is possible that the data resides in a data store on a remote node and, if that node goes down or a network failure occurs, a subsequent read would fail. Another scenario is if the data is deleted in between the calls to exists and read

Default implementation delegates to read(LogicalDatastoreType, InstanceIdentifier), implementations are advised to provide a more efficient override.

Parameters:

store - Logical data store from which read should occur.

path - Path which uniquely identifies subtree which client want to check existence of

Returns:

a CheckFuture containing the result of the check.

• If the data at the supplied path exists, the Future returns a Boolean whose value is true, false otherwise
• If checking for the data fails, the Future will fail with a ReadFailedException or an exception derived from ReadFailedException.