/*
* 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.yangtools.yang.data.impl.schema.tree;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import java.util.Collection;
import java.util.Map;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.NotThreadSafe;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
import org.opendaylight.yangtools.yang.data.api.schema.tree.StoreTreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
/**
* Node Modification Node and Tree
*
* Tree which structurally resembles data tree and captures client modifications to the data store tree. This tree is
* lazily created and populated via {@link #modifyChild(PathArgument, ModificationApplyOperation, Version)} and
* {@link TreeNode} which represents original state as tracked by {@link #getOriginal()}.
*
* The contract is that the state information exposed here preserves the temporal ordering of whatever modifications
* were executed. A child's effects pertain to data node as modified by its ancestors. This means that in order to
* reconstruct the effective data node presentation, it is sufficient to perform a depth-first pre-order traversal of
* the tree.
*/
@NotThreadSafe
final class ModifiedNode extends NodeModification implements StoreTreeNode<ModifiedNode> {
static final Predicate<ModifiedNode> IS_TERMINAL_PREDICATE = input -> {
Preconditions.checkNotNull(input);
switch (input.getOperation()) {
case DELETE:
case MERGE:
case WRITE:
return true;
case TOUCH:
case NONE:
return false;
}
throw new IllegalArgumentException(String.format("Unhandled modification type %s", input.getOperation()));
};
private final Map<PathArgument, ModifiedNode> children;
private final Optional<TreeNode> original;
private final PathArgument identifier;
private LogicalOperation operation = LogicalOperation.NONE;
private Optional<TreeNode> snapshotCache;
private NormalizedNode<?, ?> value;
private ModificationType modType;
// Alternative history introduced in WRITE nodes. Instantiated when we touch any child underneath such a node.
private TreeNode writtenOriginal;
// Internal cache for TreeNodes created as part of validation
private SchemaAwareApplyOperation validatedOp;
private Optional<TreeNode> validatedCurrent;
private TreeNode validatedNode;
private ModifiedNode(final PathArgument identifier, final Optional<TreeNode> original, final ChildTrackingPolicy childPolicy) {
this.identifier = identifier;
this.original = original;
this.children = childPolicy.createMap();
}
@Override
public PathArgument getIdentifier() {
return identifier;
}
@Override
LogicalOperation getOperation() {
return operation;
}
@Override
Optional<TreeNode> getOriginal() {
return original;
}
/**
* Return the value which was written to this node. The returned object is only valid for
* {@link LogicalOperation#MERGE} and {@link LogicalOperation#WRITE}.
* operations. It should only be consulted when this modification is going to end up being
* {@link ModificationType#WRITE}.
*
* @return Currently-written value
*/
NormalizedNode<?, ?> getWrittenValue() {
return value;
}
/**
*
* Returns child modification if child was modified
*
* @return Child modification if direct child or it's subtree
* was modified.
*
*/
@Override
public Optional<ModifiedNode> getChild(final PathArgument child) {
return Optional.fromNullable(children.get(child));
}
private Optional<TreeNode> metadataFromSnapshot(@Nonnull final PathArgument child) {
return original.isPresent() ? original.get().getChild(child) : Optional.absent();
}
private Optional<TreeNode> metadataFromData(@Nonnull final PathArgument child, final Version modVersion) {
if (writtenOriginal == null) {
// Lazy instantiation, as we do not want do this for all writes. We are using the modification's version
// here, as that version is what the SchemaAwareApplyOperation will see when dealing with the resulting
// modifications.
writtenOriginal = TreeNodeFactory.createTreeNode(value, modVersion);
}
return writtenOriginal.getChild(child);
}
/**
* Determine the base tree node we are going to apply the operation to. This is not entirely trivial because
* both DELETE and WRITE operations unconditionally detach their descendants from the original snapshot, so we need
* to take the current node's operation into account.
*
* @param child Child we are looking to modify
* @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
* @return Before-image tree node as observed by that child.
*/
private Optional<TreeNode> findOriginalMetadata(@Nonnull final PathArgument child, final Version modVersion) {
switch (operation) {
case DELETE:
// DELETE implies non-presence
return Optional.absent();
case NONE:
case TOUCH:
case MERGE:
return metadataFromSnapshot(child);
case WRITE:
// WRITE implies presence based on written data
return metadataFromData(child, modVersion);
}
throw new IllegalStateException("Unhandled node operation " + operation);
}
/**
*
* Returns child modification if child was modified, creates {@link ModifiedNode}
* for child otherwise.
*
* If this node's {@link ModificationType} is {@link ModificationType#UNMODIFIED}
* changes modification type to {@link ModificationType#SUBTREE_MODIFIED}
*
* @param child child identifier, may not be null
* @param childOper Child operation
* @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
* @return {@link ModifiedNode} for specified child, with {@link #getOriginal()}
* containing child metadata if child was present in original data.
*/
ModifiedNode modifyChild(@Nonnull final PathArgument child, @Nonnull final ModificationApplyOperation childOper,
@Nonnull final Version modVersion) {
clearSnapshot();
if (operation == LogicalOperation.NONE) {
updateOperationType(LogicalOperation.TOUCH);
}
final ModifiedNode potential = children.get(child);
if (potential != null) {
return potential;
}
final Optional<TreeNode> currentMetadata = findOriginalMetadata(child, modVersion);
final ModifiedNode newlyCreated = new ModifiedNode(child, currentMetadata, childOper.getChildPolicy());
if (operation == LogicalOperation.MERGE && value != null) {
/*
* We are attempting to modify a previously-unmodified part of a MERGE node. If the
* value contains this component, we need to materialize it as a MERGE modification.
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
final Optional<NormalizedNode<?, ?>> childData = ((NormalizedNodeContainer)value).getChild(child);
if (childData.isPresent()) {
childOper.mergeIntoModifiedNode(newlyCreated, childData.get(), modVersion);
}
}
children.put(child, newlyCreated);
return newlyCreated;
}
/**
* Returns all recorded direct child modification
*
* @return all recorded direct child modifications
*/
@Override
Collection<ModifiedNode> getChildren() {
return children.values();
}
/**
* Records a delete for associated node.
*/
void delete() {
final LogicalOperation newType;
switch (operation) {
case DELETE:
case NONE:
// We need to record this delete.
newType = LogicalOperation.DELETE;
break;
case MERGE:
// In case of merge - delete needs to be recored and must not to be changed into
// NONE, because lazy expansion of parent MERGE node would reintroduce it
// again.
newType = LogicalOperation.DELETE;
break;
case TOUCH:
case WRITE:
/*
* We are canceling a previous modification. This is a bit tricky,
* as the original write may have just introduced the data, or it
* may have modified it.
*
* As documented in BUG-2470, a delete of data introduced in this
* transaction needs to be turned into a no-op.
*/
newType = original.isPresent() ? LogicalOperation.DELETE : LogicalOperation.NONE;
break;
default:
throw new IllegalStateException("Unhandled deletion of node with " + operation);
}
clearSnapshot();
children.clear();
this.value = null;
updateOperationType(newType);
}
/**
* Records a write for associated node.
*
* @param value
*/
void write(final NormalizedNode<?, ?> value) {
updateValue(LogicalOperation.WRITE, value);
children.clear();
}
/**
* Seal the modification node and prune any children which has not been modified.
*
* @param schema
*/
void seal(final ModificationApplyOperation schema, final Version version) {
clearSnapshot();
writtenOriginal = null;
switch (operation) {
case TOUCH:
// A TOUCH node without any children is a no-op
if (children.isEmpty()) {
updateOperationType(LogicalOperation.NONE);
}
break;
case WRITE:
// A WRITE can collapse all of its children
if (!children.isEmpty()) {
value = schema.apply(this, getOriginal(), version).get().getData();
children.clear();
}
schema.verifyStructure(value, true);
break;
default:
break;
}
}
private void clearSnapshot() {
snapshotCache = null;
}
Optional<TreeNode> getSnapshot() {
return snapshotCache;
}
Optional<TreeNode> setSnapshot(final Optional<TreeNode> snapshot) {
snapshotCache = Preconditions.checkNotNull(snapshot);
return snapshot;
}
void updateOperationType(final LogicalOperation type) {
operation = type;
modType = null;
// Make sure we do not reuse previously-instantiated data-derived metadata
writtenOriginal = null;
clearSnapshot();
}
@Override
public String toString() {
return "NodeModification [identifier=" + identifier + ", modificationType="
+ operation + ", childModification=" + children + "]";
}
void resolveModificationType(@Nonnull final ModificationType type) {
modType = type;
}
/**
* Update this node's value and operation type without disturbing any of its child modifications.
*
* @param type New operation type
* @param value New node value
*/
void updateValue(final LogicalOperation type, final NormalizedNode<?, ?> value) {
this.value = Preconditions.checkNotNull(value);
updateOperationType(type);
}
/**
* Return the physical modification done to data. May return null if the
* operation has not been applied to the underlying tree. This is different
* from the logical operation in that it can actually be a no-op if the
* operation has no side-effects (like an empty merge on a container).
*
* @return Modification type.
*/
ModificationType getModificationType() {
return modType;
}
public static ModifiedNode createUnmodified(final TreeNode metadataTree, final ChildTrackingPolicy childPolicy) {
return new ModifiedNode(metadataTree.getIdentifier(), Optional.of(metadataTree), childPolicy);
}
void setValidatedNode(final SchemaAwareApplyOperation op, final Optional<TreeNode> current, final TreeNode node) {
this.validatedOp = Preconditions.checkNotNull(op);
this.validatedCurrent = Preconditions.checkNotNull(current);
this.validatedNode = Preconditions.checkNotNull(node);
}
TreeNode getValidatedNode(final SchemaAwareApplyOperation op, final Optional<TreeNode> current) {
return op.equals(validatedOp) && current.equals(validatedCurrent) ? validatedNode : null;
}
}