import com.google.common.base.Optional;
import com.google.common.util.concurrent.ListenableFuture;
+/**
+ * A transaction that provides read access to a logical data store.
+ * <p>
+ * For more information on usage and examples, please see the documentation in {@link AsyncReadTransaction}.
+ */
public interface ReadTransaction extends AsyncReadTransaction<InstanceIdentifier<?>, DataObject> {
- @Override
- ListenableFuture<Optional<DataObject>> read(LogicalDatastoreType store, InstanceIdentifier<?> path);
+
+ /**
+ * Reads data from the provided logical data store located at the provided path.
+ *<p>
+ * If the target is a subtree, then the whole subtree is read (and will be
+ * accessible from the returned data object).
+ *
+ * @param store
+ * Logical data store from which read should occur.
+ * @param path
+ * Path which uniquely identifies subtree which client want to
+ * read
+ * @return Listenable Future which contains read result
+ * <ul>
+ * <li>If data at supplied path exists the
+ * {@link ListeblaFuture#get()} returns Optional object containing
+ * data once read is done.
+ * <li>If data at supplied path does not exists the
+ * {@link ListenbleFuture#get()} returns {@link Optional#absent()}.
+ * </ul>
+ */
+ <T extends DataObject> ListenableFuture<Optional<T>> read(LogicalDatastoreType store, InstanceIdentifier<T> path);
}