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.DOMDataTreeListener;
22 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducer;
23 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerBusyException;
24 import org.opendaylight.mdsal.dom.api.DOMDataTreeProducerException;
25 import org.opendaylight.mdsal.dom.api.DOMDataTreeShard;
26 import org.slf4j.Logger;
27 import org.slf4j.LoggerFactory;
29 class ShardedDOMDataTreeProducer implements DOMDataTreeProducer {
30 private static final Logger LOG = LoggerFactory.getLogger(ShardedDOMDataTreeProducer.class);
32 private final Set<DOMDataTreeIdentifier> subtrees;
33 private final ShardedDOMDataTree dataTree;
35 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
36 CURRENT_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
37 ShardedDOMDataTreeWriteTransaction.class, "currentTx");
38 private volatile ShardedDOMDataTreeWriteTransaction currentTx;
40 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
41 OPEN_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
42 ShardedDOMDataTreeWriteTransaction.class, "openTx");
43 private volatile ShardedDOMDataTreeWriteTransaction openTx;
45 private static final AtomicReferenceFieldUpdater<ShardedDOMDataTreeProducer, ShardedDOMDataTreeWriteTransaction>
46 LAST_UPDATER = AtomicReferenceFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class,
47 ShardedDOMDataTreeWriteTransaction.class, "lastTx");
48 private volatile ShardedDOMDataTreeWriteTransaction lastTx;
50 private static final AtomicIntegerFieldUpdater<ShardedDOMDataTreeProducer> CLOSED_UPDATER =
51 AtomicIntegerFieldUpdater.newUpdater(ShardedDOMDataTreeProducer.class, "closed");
52 private volatile int closed;
54 private volatile DOMDataTreeListener attachedListener;
55 private volatile ProducerLayout layout;
57 ShardedDOMDataTreeProducer(final ShardedDOMDataTree dataTree,
58 final Collection<DOMDataTreeIdentifier> subtrees,
59 final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
60 this.dataTree = Preconditions.checkNotNull(dataTree);
61 this.subtrees = ImmutableSet.copyOf(subtrees);
62 this.layout = ProducerLayout.create(shardMap);
65 static DOMDataTreeProducer create(final ShardedDOMDataTree dataTree,
66 final Collection<DOMDataTreeIdentifier> subtrees,
67 final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
68 return new ShardedDOMDataTreeProducer(dataTree, subtrees, shardMap);
71 private void checkNotClosed() {
72 Preconditions.checkState(closed == 0, "Producer is already closed");
75 private void checkIdle() {
76 Preconditions.checkState(openTx == null, "Transaction %s is still open", openTx);
79 void subshardAdded(final Map<DOMDataTreeIdentifier, DOMDataTreeShard> shardMap) {
82 layout = layout.reshard(shardMap);
86 public DOMDataTreeCursorAwareTransaction createTransaction(final boolean isolated) {
90 LOG.debug("Creating transaction from producer {}", this);
92 final ShardedDOMDataTreeWriteTransaction current = CURRENT_UPDATER.getAndSet(this, null);
93 final ShardedDOMDataTreeWriteTransaction ret;
95 ret = createIsolatedTransaction(layout, current);
97 ret = createReusedTransaction(layout, current);
100 final boolean success = OPEN_UPDATER.compareAndSet(this, null, ret);
101 Preconditions.checkState(success, "Illegal concurrent access to producer %s detected", this);
105 // This may look weird, but this has side-effects on local's producers, hence it needs to be properly synchronized
106 // so that it happens-after submitTransaction() which may have been stolen by a callback.
108 private ShardedDOMDataTreeWriteTransaction createTransaction(final ProducerLayout local) {
109 return new ShardedDOMDataTreeWriteTransaction(this, local.createTransactions(), local);
113 // Isolated case. If we have a previous transaction, submit it before returning this one.
114 private synchronized ShardedDOMDataTreeWriteTransaction createIsolatedTransaction(
115 final ProducerLayout local, final ShardedDOMDataTreeWriteTransaction current) {
116 if (current != null) {
117 submitTransaction(current);
120 return createTransaction(local);
123 private ShardedDOMDataTreeWriteTransaction createReusedTransaction(final ProducerLayout local,
124 final ShardedDOMDataTreeWriteTransaction current) {
125 if (current != null) {
126 // Lock-free fast path
127 if (local.equals(current.getLayout())) {
128 LOG.debug("Reusing previous transaction {} since there is still a transaction inflight",
129 current.getIdentifier());
133 synchronized (this) {
134 submitTransaction(current);
135 return createTransaction(local);
139 // Null indicates we have not seen a previous transaction -- which does not mean it is ready, as it may have
140 // been stolen and in is process of being submitted.
141 synchronized (this) {
142 return createTransaction(local);
147 private void submitTransaction(final ShardedDOMDataTreeWriteTransaction tx) {
149 tx.doSubmit(this::transactionSuccessful, this::transactionFailed);
153 @SuppressWarnings("checkstyle:hiddenField")
154 public DOMDataTreeProducer createProducer(final Collection<DOMDataTreeIdentifier> subtrees) {
158 final ProducerLayout local = layout;
160 for (final DOMDataTreeIdentifier s : subtrees) {
161 // Check if the subtree was visible at any time
162 Preconditions.checkArgument(local.haveSubtree(s), "Subtree %s was never available in producer %s", s, this);
163 // Check if the subtree has not been delegated to a child
164 final DOMDataTreeProducer child = local.lookupChild(s);
165 Preconditions.checkArgument(child == null, "Subtree %s is delegated to child producer %s", s, child);
167 // Check if part of the requested subtree is not delegated to a child.
168 for (final DOMDataTreeIdentifier c : local.getChildTrees()) {
169 Preconditions.checkArgument(!s.contains(c),
170 "Subtree %s cannot be delegated as it is a superset of already-delegated %s", s, c);
175 final DOMDataTreeProducer ret;
176 synchronized (this) {
177 ret = dataTree.createProducer(this, subtrees);
180 layout = local.addChild(ret, subtrees);
184 boolean isDelegatedToChild(final DOMDataTreeIdentifier path) {
185 return layout.lookupChild(path) != null;
189 public void close() throws DOMDataTreeProducerException {
190 if (openTx != null) {
191 throw new DOMDataTreeProducerBusyException(String.format("Transaction %s is still open", openTx));
194 if (CLOSED_UPDATER.compareAndSet(this, 0, 1)) {
195 synchronized (this) {
196 dataTree.destroyProducer(this);
201 protected Set<DOMDataTreeIdentifier> getSubtrees() {
205 void cancelTransaction(final ShardedDOMDataTreeWriteTransaction transaction) {
206 final boolean success = OPEN_UPDATER.compareAndSet(this, transaction, null);
208 LOG.debug("Transaction {} cancelled", transaction);
210 LOG.warn("Transaction {} is not open in producer {}", transaction, this);
214 // Called when the user submits a transaction
215 void transactionSubmitted(final ShardedDOMDataTreeWriteTransaction transaction) {
216 final boolean wasOpen = OPEN_UPDATER.compareAndSet(this, transaction, null);
217 Preconditions.checkState(wasOpen, "Attempted to submit non-open transaction %s", transaction);
219 if (lastTx == null) {
220 // No transaction outstanding, we need to submit it now
221 synchronized (this) {
222 submitTransaction(transaction);
228 // There is a potentially-racing submitted transaction. Publish the new one, which may end up being
229 // picked up by processNextTransaction.
230 final boolean success = CURRENT_UPDATER.compareAndSet(this, null, transaction);
231 Verify.verify(success);
233 // Now a quick check: if the racing transaction completed in between, it may have missed the current
234 // transaction, hence we need to re-check
235 if (lastTx == null) {
236 submitCurrentTransaction();
240 private void submitCurrentTransaction() {
241 final ShardedDOMDataTreeWriteTransaction current = currentTx;
242 if (current != null) {
243 synchronized (this) {
244 if (CURRENT_UPDATER.compareAndSet(this, current, null)) {
245 submitTransaction(current);
251 private void transactionSuccessful(final ShardedDOMDataTreeWriteTransaction tx) {
252 LOG.debug("Transaction {} completed successfully", tx.getIdentifier());
254 tx.onTransactionSuccess(null);
255 transactionCompleted(tx);
258 private void transactionFailed(final ShardedDOMDataTreeWriteTransaction tx, final Throwable throwable) {
259 LOG.debug("Transaction {} failed", tx.getIdentifier(), throwable);
261 tx.onTransactionFailure(throwable);
262 // FIXME: transaction failure should result in a hard error
263 transactionCompleted(tx);
266 private void transactionCompleted(final ShardedDOMDataTreeWriteTransaction tx) {
267 final boolean wasLast = LAST_UPDATER.compareAndSet(this, tx, null);
269 submitCurrentTransaction();
273 void bindToListener(final DOMDataTreeListener listener) {
274 final DOMDataTreeListener local = attachedListener;
275 Preconditions.checkState(local == null, "Producer %s is already attached to listener %s", this, local);
276 this.attachedListener = Preconditions.checkNotNull(listener);