2 * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.dom.broker;
10 import com.google.common.base.Preconditions;
11 import com.google.common.base.Verify;
12 import com.google.common.collect.ImmutableSet;
13 import java.util.Collection;
16 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
17 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
18 import javax.annotation.concurrent.GuardedBy;
19 import org.opendaylight.mdsal.dom.api.DOMDataTreeCursorAwareTransaction;
20 import org.opendaylight.mdsal.dom.api.DOMDataTreeIdentifier;
21 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer;
22 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerBusyException;
23 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerException;
24 import org.opendaylight.mdsal.dom.api.DOMDataTreeShard;
25 import org.slf4j.Logger;
26 import org.slf4j.LoggerFactory;
28 class ShardedDOMDataTreeProducer implements DOMDataTreeProducer {
29 private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMDataTreeProducer.class);
31 private final Set<DOMDataTreeIdentifier> subtrees;
32 private final ShardedDOMDataTree dataTree;
34 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
35 CURRENT_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
36 ShardedDOMDataTreeWriteTransaction.class, "currentTx");
37 private volatile ShardedDOMDataTreeWriteTransaction currentTx;
39 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
40 OPEN_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
41 ShardedDOMDataTreeWriteTransaction.class, "openTx");
42 private volatile ShardedDOMDataTreeWriteTransaction openTx;
44 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
45 LAST_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
46 ShardedDOMDataTreeWriteTransaction.class, "lastTx");
47 private volatile ShardedDOMDataTreeWriteTransaction lastTx;
49 private static final AtomicIntegerFieldUpdater<ShardedDOMDataTreeProducer> CLOSED_UPDATER =
50 AtomicIntegerFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class, "closed");
51 private volatile int closed;
53 private volatile ShardedDOMDataTreeListenerContext<?> attachedListener;
54 private volatile ProducerLayout layout;
56 private ShardedDOMDataTreeProducer(final ShardedDOMDataTree dataTree,
57 final Collection<DOMDataTreeIdentifier> subtrees,
58 final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
59 this.dataTree = Preconditions.checkNotNull(dataTree);
60 this.subtrees = ImmutableSet.copyOf(subtrees);
61 this.layout = ProducerLayout.create(shardMap);
64 static DOMDataTreeProducer create(final ShardedDOMDataTree dataTree,
65 final Collection<DOMDataTreeIdentifier> subtrees,
66 final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
67 return new ShardedDOMDataTreeProducer(dataTree, subtrees, shardMap);
70 private void checkNotClosed() {
71 Preconditions.checkState(closed == 0, "Producer is already closed");
74 private void checkIdle() {
75 Preconditions.checkState(openTx == null, "Transaction %s is still open", openTx);
78 void subshardAdded(final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
81 layout = layout.reshard(shardMap);
85 public DOMDataTreeCursorAwareTransaction createTransaction(final boolean isolated) {
89 LOG.debug("Creating transaction from producer {}", this);
91 final ShardedDOMDataTreeWriteTransaction current = CURRENT_UPDATER.getAndSet(this, null);
92 final ShardedDOMDataTreeWriteTransaction ret;
94 ret = createIsolatedTransaction(layout, current);
96 ret = createReusedTransaction(layout, current);
99 final boolean success = OPEN_UPDATER.compareAndSet(this, null, ret);
100 Preconditions.checkState(success, "Illegal concurrent access to producer %s detected", this);
104 // This may look weird, but this has side-effects on local's producers, hence it needs to be properly synchronized
105 // so that it happens-after submitTransaction() which may have been stolen by a callback.
107 private ShardedDOMDataTreeWriteTransaction createTransaction(final ProducerLayout local) {
108 return new ShardedDOMDataTreeWriteTransaction(this, local.createTransactions(), local);
112 // Isolated case. If we have a previous transaction, submit it before returning this one.
113 private synchronized ShardedDOMDataTreeWriteTransaction createIsolatedTransaction(
114 final ProducerLayout local, final ShardedDOMDataTreeWriteTransaction current) {
115 if (current != null) {
116 submitTransaction(current);
119 return createTransaction(local);
122 private ShardedDOMDataTreeWriteTransaction createReusedTransaction(final ProducerLayout local,
123 final ShardedDOMDataTreeWriteTransaction current) {
124 if (current != null) {
125 // Lock-free fast path
126 if (local.equals(current.getLayout())) {
127 LOG.debug("Reusing previous transaction {} since there is still a transaction inflight",
128 current.getIdentifier());
132 synchronized (this) {
133 submitTransaction(current);
134 return createTransaction(local);
138 // Null indicates we have not seen a previous transaction -- which does not mean it is ready, as it may have
139 // been stolen and in is process of being submitted.
140 synchronized (this) {
141 return createTransaction(local);
146 private void submitTransaction(final ShardedDOMDataTreeWriteTransaction tx) {
148 tx.doSubmit(this::transactionSuccessful, this::transactionFailed);
152 public DOMDataTreeProducer createProducer(final Collection<DOMDataTreeIdentifier> subtrees) {
156 final ProducerLayout local = layout;
158 for (final DOMDataTreeIdentifier s : subtrees) {
159 // Check if the subtree was visible at any time
160 Preconditions.checkArgument(local.haveSubtree(s), "Subtree %s was never available in producer %s", s, this);
161 // Check if the subtree has not been delegated to a child
162 final DOMDataTreeProducer child = local.lookupChild(s);
163 Preconditions.checkArgument(child == null, "Subtree %s is delegated to child producer %s", s, child);
165 // Check if part of the requested subtree is not delegated to a child.
166 for (final DOMDataTreeIdentifier c : local.getChildTrees()) {
167 Preconditions.checkArgument(!s.contains(c),
168 "Subtree %s cannot be delegated as it is a superset of already-delegated %s", s, c);
173 final DOMDataTreeProducer ret;
174 synchronized (this) {
175 ret = dataTree.createProducer(this, subtrees);
178 layout = local.addChild(ret, subtrees);
182 boolean isDelegatedToChild(final DOMDataTreeIdentifier path) {
183 return layout.lookupChild(path) != null;
187 public void close() throws DOMDataTreeProducerException {
188 if (openTx != null) {
189 throw new DOMDataTreeProducerBusyException(String.format("Transaction %s is still open", openTx));
192 if (CLOSED_UPDATER.compareAndSet(this, 0, 1)) {
193 synchronized (this) {
194 dataTree.destroyProducer(this);
199 protected Set<DOMDataTreeIdentifier> getSubtrees() {
203 void cancelTransaction(final ShardedDOMDataTreeWriteTransaction transaction) {
204 final boolean success = OPEN_UPDATER.compareAndSet(this, transaction, null);
206 LOG.debug("Transaction {} cancelled", transaction);
208 LOG.warn("Transaction {} is not open in producer {}", transaction, this);
212 // Called when the user submits a transaction
213 void transactionSubmitted(final ShardedDOMDataTreeWriteTransaction transaction) {
214 final boolean wasOpen = OPEN_UPDATER.compareAndSet(this, transaction, null);
215 Preconditions.checkState(wasOpen, "Attempted to submit non-open transaction %s", transaction);
217 if (lastTx == null) {
218 // No transaction outstanding, we need to submit it now
219 synchronized (this) {
220 submitTransaction(transaction);
226 // There is a potentially-racing submitted transaction. Publish the new one, which may end up being
227 // picked up by processNextTransaction.
228 final boolean success = CURRENT_UPDATER.compareAndSet(this, null, transaction);
229 Verify.verify(success);
231 // Now a quick check: if the racing transaction completed in between, it may have missed the current
232 // transaction, hence we need to re-check
233 if (lastTx == null) {
234 submitCurrentTransaction();
238 private void submitCurrentTransaction() {
239 final ShardedDOMDataTreeWriteTransaction current = currentTx;
240 if (current != null) {
241 synchronized (this) {
242 if (CURRENT_UPDATER.compareAndSet(this, current, null)) {
243 submitTransaction(current);
249 private void transactionSuccessful(final ShardedDOMDataTreeWriteTransaction tx) {
250 LOG.debug("Transaction {} completed successfully", tx.getIdentifier());
252 tx.onTransactionSuccess(null);
253 transactionCompleted(tx);
256 private void transactionFailed(final ShardedDOMDataTreeWriteTransaction tx, final Throwable throwable) {
257 LOG.debug("Transaction {} failed", tx.getIdentifier(), throwable);
259 tx.onTransactionFailure(throwable);
260 // FIXME: transaction failure should result in a hard error
261 transactionCompleted(tx);
264 private void transactionCompleted(final ShardedDOMDataTreeWriteTransaction tx) {
265 final boolean wasLast = LAST_UPDATER.compareAndSet(this, tx, null);
267 submitCurrentTransaction();
271 void bindToListener(final ShardedDOMDataTreeListenerContext<?> listener) {
272 Preconditions.checkNotNull(listener);
274 final ShardedDOMDataTreeListenerContext<?> local = attachedListener;
276 throw new IllegalStateException(String.format("Producer %s is already attached to listener %s", this,
277 local.getListener()));
280 this.attachedListener = listener;