/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.sal.core.spi.data;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.Beta;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.Futures;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Implementation of read-only transaction backed by {@link DataTreeSnapshot}.
*
*
* Implementation of read-only transaction backed by {@link DataTreeSnapshot}
* which delegates most of its calls to similar methods provided by underlying snapshot.
*
* @param identifier type
*/
@Beta
public final class SnapshotBackedReadTransaction extends AbstractDOMStoreTransaction
implements DOMStoreReadTransaction {
private static final Logger LOG = LoggerFactory.getLogger(SnapshotBackedReadTransaction.class);
private volatile DataTreeSnapshot stableSnapshot;
/**
* Creates a new read-only transaction.
*
* @param identifier Transaction Identifier
* @param debug Enable transaction debugging
* @param snapshot Snapshot which will be modified.
*/
SnapshotBackedReadTransaction(final T identifier, final boolean debug, final DataTreeSnapshot snapshot) {
super(identifier, debug);
this.stableSnapshot = Preconditions.checkNotNull(snapshot);
LOG.debug("ReadOnly Tx: {} allocated with snapshot {}", identifier, snapshot);
}
@Override
public void close() {
LOG.debug("Store transaction: {} : Closed", getIdentifier());
stableSnapshot = null;
}
@Override
@SuppressWarnings("checkstyle:IllegalCatch")
public CheckedFuture>, ReadFailedException> read(final YangInstanceIdentifier path) {
LOG.debug("Tx: {} Read: {}", getIdentifier(), path);
checkNotNull(path, "Path must not be null.");
final DataTreeSnapshot snapshot = stableSnapshot;
if (snapshot == null) {
return Futures.immediateFailedCheckedFuture(new ReadFailedException("Transaction is closed"));
}
try {
return Futures.immediateCheckedFuture(Optional.fromJavaUtil(snapshot.readNode(path)));
} catch (RuntimeException e) {
LOG.error("Tx: {} Failed Read of {}", getIdentifier(), path, e);
return Futures.immediateFailedCheckedFuture(new ReadFailedException("Read failed",e));
}
}
@Override
public CheckedFuture exists(final YangInstanceIdentifier path) {
LOG.debug("Tx: {} Exists: {}", getIdentifier(), path);
checkNotNull(path, "Path must not be null.");
try {
return Futures.immediateCheckedFuture(read(path).checkedGet().isPresent());
} catch (ReadFailedException e) {
return Futures.immediateFailedCheckedFuture(e);
}
}
}