2 * Copyright (c) 2014 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.yangtools.yang.data.impl.schema.tree;
10 import static java.util.Objects.requireNonNull;
12 import com.google.common.base.MoreObjects;
13 import com.google.common.base.MoreObjects.ToStringHelper;
14 import java.util.Collection;
16 import java.util.Optional;
17 import java.util.function.Predicate;
18 import javax.annotation.Nonnull;
19 import javax.annotation.concurrent.NotThreadSafe;
20 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
21 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
22 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
23 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
24 import org.opendaylight.yangtools.yang.data.api.schema.tree.StoreTreeNode;
25 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
26 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
27 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
30 * Node Modification Node and Tree.
33 * Tree which structurally resembles data tree and captures client modifications to the data store tree. This tree is
34 * lazily created and populated via {@link #modifyChild(PathArgument, ModificationApplyOperation, Version)} and
35 * {@link TreeNode} which represents original state as tracked by {@link #getOriginal()}.
38 * The contract is that the state information exposed here preserves the temporal ordering of whatever modifications
39 * were executed. A child's effects pertain to data node as modified by its ancestors. This means that in order to
40 * reconstruct the effective data node presentation, it is sufficient to perform a depth-first pre-order traversal of
44 final class ModifiedNode extends NodeModification implements StoreTreeNode<ModifiedNode> {
45 static final Predicate<ModifiedNode> IS_TERMINAL_PREDICATE = input -> {
46 requireNonNull(input);
47 switch (input.getOperation()) {
56 throw new IllegalArgumentException("Unhandled modification type " + input.getOperation());
60 private final Map<PathArgument, ModifiedNode> children;
61 private final Optional<TreeNode> original;
62 private final PathArgument identifier;
63 private LogicalOperation operation = LogicalOperation.NONE;
64 private Optional<TreeNode> snapshotCache;
65 private NormalizedNode<?, ?> value;
66 private ModificationType modType;
68 // Alternative history introduced in WRITE nodes. Instantiated when we touch any child underneath such a node.
69 private TreeNode writtenOriginal;
71 // Internal cache for TreeNodes created as part of validation
72 private ModificationApplyOperation validatedOp;
73 private Optional<TreeNode> validatedCurrent;
74 private Optional<TreeNode> validatedNode;
76 private ModifiedNode(final PathArgument identifier, final Optional<TreeNode> original,
77 final ChildTrackingPolicy childPolicy) {
78 this.identifier = identifier;
79 this.original = original;
80 this.children = childPolicy.createMap();
84 public PathArgument getIdentifier() {
89 LogicalOperation getOperation() {
94 Optional<TreeNode> getOriginal() {
99 * Return the value which was written to this node. The returned object is only valid for
100 * {@link LogicalOperation#MERGE} and {@link LogicalOperation#WRITE}.
101 * operations. It should only be consulted when this modification is going to end up being
102 * {@link ModificationType#WRITE}.
104 * @return Currently-written value
106 NormalizedNode<?, ?> getWrittenValue() {
111 * Returns child modification if child was modified.
113 * @return Child modification if direct child or it's subtree was modified.
116 public Optional<ModifiedNode> getChild(final PathArgument child) {
117 return Optional.ofNullable(children.get(child));
120 private Optional<TreeNode> metadataFromSnapshot(@Nonnull final PathArgument child) {
121 return original.isPresent() ? original.get().getChild(child) : Optional.empty();
124 private Optional<TreeNode> metadataFromData(@Nonnull final PathArgument child, final Version modVersion) {
125 if (writtenOriginal == null) {
126 // Lazy instantiation, as we do not want do this for all writes. We are using the modification's version
127 // here, as that version is what the SchemaAwareApplyOperation will see when dealing with the resulting
129 writtenOriginal = TreeNodeFactory.createTreeNode(value, modVersion);
132 return writtenOriginal.getChild(child);
136 * Determine the base tree node we are going to apply the operation to. This is not entirely trivial because
137 * both DELETE and WRITE operations unconditionally detach their descendants from the original snapshot, so we need
138 * to take the current node's operation into account.
140 * @param child Child we are looking to modify
141 * @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
142 * @return Before-image tree node as observed by that child.
144 private Optional<TreeNode> findOriginalMetadata(@Nonnull final PathArgument child, final Version modVersion) {
147 // DELETE implies non-presence
148 return Optional.empty();
152 return metadataFromSnapshot(child);
154 // WRITE implies presence based on written data
155 return metadataFromData(child, modVersion);
157 throw new IllegalStateException("Unhandled node operation " + operation);
162 * Returns child modification if child was modified, creates {@link ModifiedNode}
163 * for child otherwise. If this node's {@link ModificationType} is {@link ModificationType#UNMODIFIED}
164 * changes modification type to {@link ModificationType#SUBTREE_MODIFIED}.
166 * @param child child identifier, may not be null
167 * @param childOper Child operation
168 * @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
169 * @return {@link ModifiedNode} for specified child, with {@link #getOriginal()}
170 * containing child metadata if child was present in original data.
172 ModifiedNode modifyChild(@Nonnull final PathArgument child, @Nonnull final ModificationApplyOperation childOper,
173 @Nonnull final Version modVersion) {
175 if (operation == LogicalOperation.NONE) {
176 updateOperationType(LogicalOperation.TOUCH);
178 final ModifiedNode potential = children.get(child);
179 if (potential != null) {
183 final Optional<TreeNode> currentMetadata = findOriginalMetadata(child, modVersion);
186 final ModifiedNode newlyCreated = new ModifiedNode(child, currentMetadata, childOper.getChildPolicy());
187 if (operation == LogicalOperation.MERGE && value != null) {
189 * We are attempting to modify a previously-unmodified part of a MERGE node. If the
190 * value contains this component, we need to materialize it as a MERGE modification.
192 @SuppressWarnings({ "rawtypes", "unchecked" })
193 final Optional<NormalizedNode<?, ?>> childData = ((NormalizedNodeContainer)value).getChild(child);
194 if (childData.isPresent()) {
195 childOper.mergeIntoModifiedNode(newlyCreated, childData.get(), modVersion);
199 children.put(child, newlyCreated);
204 * Returns all recorded direct child modifications.
206 * @return all recorded direct child modifications
209 Collection<ModifiedNode> getChildren() {
210 return children.values();
214 * Records a delete for associated node.
217 final LogicalOperation newType;
222 // We need to record this delete.
223 newType = LogicalOperation.DELETE;
226 // In case of merge - delete needs to be recored and must not to be changed into NONE, because lazy
227 // expansion of parent MERGE node would reintroduce it again.
228 newType = LogicalOperation.DELETE;
233 * We are canceling a previous modification. This is a bit tricky, as the original write may have just
234 * introduced the data, or it may have modified it.
236 * As documented in BUG-2470, a delete of data introduced in this transaction needs to be turned into
239 newType = original.isPresent() ? LogicalOperation.DELETE : LogicalOperation.NONE;
242 throw new IllegalStateException("Unhandled deletion of node with " + operation);
248 updateOperationType(newType);
252 * Records a write for associated node.
254 * @param newValue new value
256 void write(final NormalizedNode<?, ?> newValue) {
257 updateValue(LogicalOperation.WRITE, newValue);
262 * Seal the modification node and prune any children which has not been modified.
264 * @param schema associated apply operation
265 * @param version target version
267 void seal(final ModificationApplyOperation schema, final Version version) {
269 writtenOriginal = null;
273 // A TOUCH node without any children is a no-op
274 if (children.isEmpty()) {
275 updateOperationType(LogicalOperation.NONE);
279 // A WRITE can collapse all of its children
280 if (!children.isEmpty()) {
281 value = schema.apply(this, getOriginal(), version).map(TreeNode::getData).orElse(null);
286 // The write has ended up being empty, such as a write of an empty list.
287 updateOperationType(LogicalOperation.DELETE);
289 schema.verifyStructure(value, true);
297 private void clearSnapshot() {
298 snapshotCache = null;
301 Optional<TreeNode> getSnapshot() {
302 return snapshotCache;
305 Optional<TreeNode> setSnapshot(final Optional<TreeNode> snapshot) {
306 snapshotCache = requireNonNull(snapshot);
310 void updateOperationType(final LogicalOperation type) {
314 // Make sure we do not reuse previously-instantiated data-derived metadata
315 writtenOriginal = null;
320 public String toString() {
321 final ToStringHelper helper = MoreObjects.toStringHelper(this).omitNullValues()
322 .add("identifier", identifier).add("operation", operation).add("modificationType", modType);
323 if (!children.isEmpty()) {
324 helper.add("childModification", children);
326 return helper.toString();
329 void resolveModificationType(@Nonnull final ModificationType type) {
334 * Update this node's value and operation type without disturbing any of its child modifications.
336 * @param type New operation type
337 * @param newValue New node value
339 void updateValue(final LogicalOperation type, final NormalizedNode<?, ?> newValue) {
340 this.value = requireNonNull(newValue);
341 updateOperationType(type);
345 * Return the physical modification done to data. May return null if the
346 * operation has not been applied to the underlying tree. This is different
347 * from the logical operation in that it can actually be a no-op if the
348 * operation has no side-effects (like an empty merge on a container).
350 * @return Modification type.
352 ModificationType getModificationType() {
356 public static ModifiedNode createUnmodified(final TreeNode metadataTree, final ChildTrackingPolicy childPolicy) {
357 return new ModifiedNode(metadataTree.getIdentifier(), Optional.of(metadataTree), childPolicy);
360 void setValidatedNode(final ModificationApplyOperation op, final Optional<TreeNode> current,
361 final Optional<TreeNode> node) {
362 this.validatedOp = requireNonNull(op);
363 this.validatedCurrent = requireNonNull(current);
364 this.validatedNode = requireNonNull(node);
367 Optional<TreeNode> getValidatedNode(final ModificationApplyOperation op, final Optional<TreeNode> current) {
368 return op.equals(validatedOp) && current.equals(validatedCurrent) ? validatedNode : null;