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 com.google.common.base.Optional;
11 import com.google.common.base.Preconditions;
12 import com.google.common.base.Predicate;
13 import java.util.Collection;
15 import javax.annotation.Nonnull;
16 import javax.annotation.Nullable;
17 import javax.annotation.concurrent.NotThreadSafe;
18 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
19 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
20 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
21 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
22 import org.opendaylight.yangtools.yang.data.api.schema.tree.StoreTreeNode;
23 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
24 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
25 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
28 * Node Modification Node and Tree
30 * Tree which structurally resembles data tree and captures client modifications to the data store tree. This tree is
31 * lazily created and populated via {@link #modifyChild(PathArgument, ModificationApplyOperation, Version)} and
32 * {@link TreeNode} which represents original state as tracked by {@link #getOriginal()}.
34 * The contract is that the state information exposed here preserves the temporal ordering of whatever modifications
35 * were executed. A child's effects pertain to data node as modified by its ancestors. This means that in order to
36 * reconstruct the effective data node presentation, it is sufficient to perform a depth-first pre-order traversal of
40 final class ModifiedNode extends NodeModification implements StoreTreeNode<ModifiedNode> {
41 static final Predicate<ModifiedNode> IS_TERMINAL_PREDICATE = new Predicate<ModifiedNode>() {
43 public boolean apply(@Nullable final ModifiedNode input) {
44 Preconditions.checkNotNull(input);
45 switch (input.getOperation()) {
55 throw new IllegalArgumentException(String.format("Unhandled modification type %s", input.getOperation()));
59 private final Map<PathArgument, ModifiedNode> children;
60 private final Optional<TreeNode> original;
61 private final PathArgument identifier;
62 private LogicalOperation operation = LogicalOperation.NONE;
63 private Optional<TreeNode> snapshotCache;
64 private NormalizedNode<?, ?> value;
65 private ModificationType modType;
67 // Alternative history introduced in WRITE nodes. Instantiated when we touch any child underneath such a node.
68 private TreeNode writtenOriginal;
70 // Internal cache for TreeNodes created as part of validation
71 private SchemaAwareApplyOperation validatedOp;
72 private Optional<TreeNode> validatedCurrent;
73 private TreeNode validatedNode;
75 private ModifiedNode(final PathArgument identifier, final Optional<TreeNode> original, final ChildTrackingPolicy childPolicy) {
76 this.identifier = identifier;
77 this.original = original;
78 this.children = childPolicy.createMap();
82 public PathArgument getIdentifier() {
87 LogicalOperation getOperation() {
92 Optional<TreeNode> getOriginal() {
97 * Return the value which was written to this node. The returned object is only valid for
98 * {@link LogicalOperation#MERGE} and {@link LogicalOperation#WRITE}.
99 * operations. It should only be consulted when this modification is going to end up being
100 * {@link ModificationType#WRITE}.
102 * @return Currently-written value
104 NormalizedNode<?, ?> getWrittenValue() {
110 * Returns child modification if child was modified
112 * @return Child modification if direct child or it's subtree
117 public Optional<ModifiedNode> getChild(final PathArgument child) {
118 return Optional.fromNullable(children.get(child));
121 private Optional<TreeNode> metadataFromSnapshot(@Nonnull final PathArgument child) {
122 return original.isPresent() ? original.get().getChild(child) : Optional.<TreeNode>absent();
125 private Optional<TreeNode> metadataFromData(@Nonnull final PathArgument child, final Version modVersion) {
126 if (writtenOriginal == null) {
127 // Lazy instantiation, as we do not want do this for all writes. We are using the modification's version
128 // here, as that version is what the SchemaAwareApplyOperation will see when dealing with the resulting
130 writtenOriginal = TreeNodeFactory.createTreeNode(value, modVersion);
133 return writtenOriginal.getChild(child);
137 * Determine the base tree node we are going to apply the operation to. This is not entirely trivial because
138 * both DELETE and WRITE operations unconditionally detach their descendants from the original snapshot, so we need
139 * to take the current node's operation into account.
141 * @param child Child we are looking to modify
142 * @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
143 * @return Before-image tree node as observed by that child.
145 private Optional<TreeNode> findOriginalMetadata(@Nonnull final PathArgument child, final Version modVersion) {
148 // DELETE implies non-presence
149 return Optional.absent();
153 return metadataFromSnapshot(child);
155 // WRITE implies presence based on written data
156 return metadataFromData(child, modVersion);
159 throw new IllegalStateException("Unhandled node operation " + operation);
164 * Returns child modification if child was modified, creates {@link ModifiedNode}
165 * for child otherwise.
167 * If this node's {@link ModificationType} is {@link ModificationType#UNMODIFIED}
168 * changes modification type to {@link ModificationType#SUBTREE_MODIFIED}
170 * @param child child identifier, may not be null
171 * @param childOper Child operation
172 * @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
173 * @return {@link ModifiedNode} for specified child, with {@link #getOriginal()}
174 * containing child metadata if child was present in original data.
176 ModifiedNode modifyChild(@Nonnull final PathArgument child, @Nonnull final ModificationApplyOperation childOper,
177 @Nonnull final Version modVersion) {
179 if (operation == LogicalOperation.NONE) {
180 updateOperationType(LogicalOperation.TOUCH);
182 final ModifiedNode potential = children.get(child);
183 if (potential != null) {
187 final Optional<TreeNode> currentMetadata = findOriginalMetadata(child, modVersion);
190 final ModifiedNode newlyCreated = new ModifiedNode(child, currentMetadata, childOper.getChildPolicy());
191 if (operation == LogicalOperation.MERGE && value != null) {
193 * We are attempting to modify a previously-unmodified part of a MERGE node. If the
194 * value contains this component, we need to materialize it as a MERGE modification.
196 @SuppressWarnings({ "rawtypes", "unchecked" })
197 final Optional<NormalizedNode<?, ?>> childData = ((NormalizedNodeContainer)value).getChild(child);
198 if (childData.isPresent()) {
199 childOper.mergeIntoModifiedNode(newlyCreated, childData.get(), modVersion);
203 children.put(child, newlyCreated);
208 * Returns all recorded direct child modification
210 * @return all recorded direct child modifications
213 Collection<ModifiedNode> getChildren() {
214 return children.values();
218 * Records a delete for associated node.
221 final LogicalOperation newType;
226 // We need to record this delete.
227 newType = LogicalOperation.DELETE;
230 // In case of merge - delete needs to be recored and must not to be changed into
231 // NONE, because lazy expansion of parent MERGE node would reintroduce it
233 newType = LogicalOperation.DELETE;
238 * We are canceling a previous modification. This is a bit tricky,
239 * as the original write may have just introduced the data, or it
240 * may have modified it.
242 * As documented in BUG-2470, a delete of data introduced in this
243 * transaction needs to be turned into a no-op.
245 newType = original.isPresent() ? LogicalOperation.DELETE : LogicalOperation.NONE;
248 throw new IllegalStateException("Unhandled deletion of node with " + operation);
254 updateOperationType(newType);
258 * Records a write for associated node.
262 void write(final NormalizedNode<?, ?> value) {
263 updateValue(LogicalOperation.WRITE, value);
268 * Seal the modification node and prune any children which has not been modified.
272 void seal(final ModificationApplyOperation schema, final Version version) {
274 writtenOriginal = null;
278 // A TOUCH node without any children is a no-op
279 if (children.isEmpty()) {
280 updateOperationType(LogicalOperation.NONE);
284 // A WRITE can collapse all of its children
285 if (!children.isEmpty()) {
286 value = schema.apply(this, getOriginal(), version).get().getData();
290 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 = Preconditions.checkNotNull(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 return "NodeModification [identifier=" + identifier + ", modificationType="
322 + operation + ", childModification=" + children + "]";
325 void resolveModificationType(@Nonnull final ModificationType type) {
330 * Update this node's value and operation type without disturbing any of its child modifications.
332 * @param type New operation type
333 * @param value New node value
335 void updateValue(final LogicalOperation type, final NormalizedNode<?, ?> value) {
336 this.value = Preconditions.checkNotNull(value);
337 updateOperationType(type);
341 * Return the physical modification done to data. May return null if the
342 * operation has not been applied to the underlying tree. This is different
343 * from the logical operation in that it can actually be a no-op if the
344 * operation has no side-effects (like an empty merge on a container).
346 * @return Modification type.
348 ModificationType getModificationType() {
352 public static ModifiedNode createUnmodified(final TreeNode metadataTree, final ChildTrackingPolicy childPolicy) {
353 return new ModifiedNode(metadataTree.getIdentifier(), Optional.of(metadataTree), childPolicy);
356 void setValidatedNode(final SchemaAwareApplyOperation op, final Optional<TreeNode> current, final TreeNode node) {
357 this.validatedOp = Preconditions.checkNotNull(op);
358 this.validatedCurrent = Preconditions.checkNotNull(current);
359 this.validatedNode = Preconditions.checkNotNull(node);
362 TreeNode getValidatedNode(final SchemaAwareApplyOperation op, final Optional<TreeNode> current) {
363 return op.equals(validatedOp) && current.equals(validatedCurrent) ? validatedNode : null;