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.yangtools.yang.data.impl.schema.tree;
10 import java.util.Optional;
11 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
12 import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
13 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
14 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
15 import org.opendaylight.yangtools.yang.data.api.schema.OrderedNodeContainer;
16 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeConfiguration;
17 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
18 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
19 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
20 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
21 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
22 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
23 import org.opendaylight.yangtools.yang.model.api.ContainerSchemaNode;
26 * Structural containers are special in that they appear when implied by child nodes and disappear whenever they are
27 * empty. We could implement this as a subclass of {@link SchemaAwareApplyOperation}, but the automatic semantic
28 * is quite different from all the other strategies. We create a {@link ContainerModificationStrategy} to tap into that
29 * logic, but wrap it so we only call out into it. We do not use {@link PresenceContainerModificationStrategy} because
30 * it enforces presence of mandatory leaves, which is not something we want here, as structural containers are not
31 * root anchors for that validation.
33 final class StructuralContainerModificationStrategy extends ModificationApplyOperation {
35 * Fake TreeNode version used in
36 * {@link #checkApplicable(ModificationPath, NodeModification, Optional, Version)}.
37 * It is okay to use a global constant, as the delegate will ignore it anyway. For
38 * {@link #apply(ModifiedNode, Optional, Version)} we will use the appropriate version as provided to us.
40 private static final Version FAKE_VERSION = Version.initial();
42 private final ContainerModificationStrategy delegate;
43 private final ContainerNode emptyNode;
45 StructuralContainerModificationStrategy(final ContainerSchemaNode schemaNode,
46 final DataTreeConfiguration treeConfig) {
47 this.delegate = new ContainerModificationStrategy(schemaNode, treeConfig);
48 this.emptyNode = ImmutableNodes.containerNode(schemaNode.getQName());
51 private Optional<TreeNode> fakeMeta(final Version version) {
52 return Optional.of(TreeNodeFactory.createTreeNode(emptyNode, version));
56 Optional<TreeNode> apply(final ModifiedNode modification, final Optional<TreeNode> storeMeta,
57 final Version version) {
58 // The only way a tree node can disappear is through delete (which we handle here explicitly) or through
59 // actions of disappearResult(). It is therefore safe to perform Optional.get() on the results of
62 if (modification.getOperation() == LogicalOperation.DELETE) {
63 if (modification.getChildren().isEmpty()) {
64 return delegate.apply(modification, storeMeta, version);
66 // Delete with children, implies it really is an empty write
67 ret = delegate.applyWrite(modification, emptyNode, storeMeta, version);
68 } else if (modification.getOperation() == LogicalOperation.TOUCH && !storeMeta.isPresent()) {
69 ret = applyTouch(modification, storeMeta, version);
71 // No special handling required here, run normal apply operation
72 ret = delegate.apply(modification, storeMeta, version).get();
75 return disappearResult(modification, ret, storeMeta);
79 void checkApplicable(final ModificationPath path, final NodeModification modification,
80 final Optional<TreeNode> current, final Version version) throws DataValidationFailedException {
81 if (modification.getOperation() == LogicalOperation.TOUCH && !current.isPresent()) {
82 // Structural containers are created as needed, so we pretend this container is here
83 delegate.checkApplicable(path, modification, fakeMeta(FAKE_VERSION), version);
85 delegate.checkApplicable(path, modification, current, version);
90 void verifyStructure(final NormalizedNode<?, ?> modification, final boolean verifyChildren) {
91 delegate.verifyStructure(modification, verifyChildren);
95 void recursivelyVerifyStructure(final NormalizedNode<?, ?> value) {
96 delegate.recursivelyVerifyStructure(value);
100 ChildTrackingPolicy getChildPolicy() {
101 return delegate.getChildPolicy();
105 void mergeIntoModifiedNode(final ModifiedNode modification, final NormalizedNode<?, ?> value,
106 final Version version) {
107 delegate.mergeIntoModifiedNode(modification, value, version);
111 public Optional<ModificationApplyOperation> getChild(final PathArgument child) {
112 return delegate.getChild(child);
115 private TreeNode applyTouch(final ModifiedNode modification, final Optional<TreeNode> storeMeta,
116 final Version version) {
117 // Container is not present, let's take care of the 'magically appear' part of our job
118 final Optional<TreeNode> ret = delegate.apply(modification, fakeMeta(version), version);
120 // If the delegate indicated SUBTREE_MODIFIED, account for the fake and report APPEARED
121 if (modification.getModificationType() == ModificationType.SUBTREE_MODIFIED) {
122 modification.resolveModificationType(ModificationType.APPEARED);
127 private static Optional<TreeNode> disappearResult(final ModifiedNode modification, final TreeNode result,
128 final Optional<TreeNode> storeMeta) {
129 // Check if the result is in fact empty before pulling any tricks
130 if (!isEmpty(result)) {
131 return Optional.of(result);
134 // We are pulling the 'disappear' trick, but what we report can be three different things
135 final ModificationType finalType;
136 if (!storeMeta.isPresent()) {
137 // ... there was nothing in the datastore, no change
138 finalType = ModificationType.UNMODIFIED;
139 } else if (modification.getModificationType() == ModificationType.WRITE) {
140 // ... this was an empty write, possibly originally a delete
141 finalType = ModificationType.DELETE;
143 // ... it really disappeared
144 finalType = ModificationType.DISAPPEARED;
146 modification.resolveModificationType(finalType);
147 return Optional.empty();
150 private static boolean isEmpty(final TreeNode treeNode) {
151 final NormalizedNode<?, ?> data = treeNode.getData();
152 if (data instanceof NormalizedNodeContainer) {
153 return ((NormalizedNodeContainer<?, ?, ?>) data).getValue().isEmpty();
155 if (data instanceof OrderedNodeContainer) {
156 return ((OrderedNodeContainer<?>) data).getSize() == 0;
158 throw new IllegalStateException("Unhandled data " + data);