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.schema.ContainerNode;
12 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
13 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
14 import org.opendaylight.yangtools.yang.data.api.schema.OrderedNodeContainer;
15 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeConfiguration;
16 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
17 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
18 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
19 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
20 import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
21 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
22 import org.opendaylight.yangtools.yang.model.api.ContainerSchemaNode;
25 * Structural containers are special in that they appear when implied by child nodes and disappear whenever they are
26 * empty. We could implement this as a subclass of {@link SchemaAwareApplyOperation}, but the automatic semantic
27 * is quite different from all the other strategies. We create a {@link ContainerModificationStrategy} to tap into that
28 * logic, but wrap it so we only call out into it. We do not use {@link PresenceContainerModificationStrategy} because
29 * it enforces presence of mandatory leaves, which is not something we want here, as structural containers are not
30 * root anchors for that validation.
32 final class StructuralContainerModificationStrategy extends DelegatingModificationApplyOperation {
34 * Fake TreeNode version used in
35 * {@link #checkApplicable(ModificationPath, NodeModification, Optional, Version)}.
36 * It is okay to use a global constant, as the delegate will ignore it anyway. For
37 * {@link #apply(ModifiedNode, Optional, Version)} we will use the appropriate version as provided to us.
39 private static final Version FAKE_VERSION = Version.initial();
41 private final ContainerModificationStrategy delegate;
42 private final ContainerNode emptyNode;
44 StructuralContainerModificationStrategy(final ContainerSchemaNode schemaNode,
45 final DataTreeConfiguration treeConfig) {
46 this.delegate = new ContainerModificationStrategy(schemaNode, treeConfig);
47 this.emptyNode = ImmutableNodes.containerNode(schemaNode.getQName());
51 ModificationApplyOperation delegate() {
56 void fullVerifyStructure(final NormalizedNode<?, ?> modification) {
57 delegate.fullVerifyStructure(modification);
61 Optional<TreeNode> apply(final ModifiedNode modification, final Optional<TreeNode> storeMeta,
62 final Version version) {
63 // The only way a tree node can disappear is through delete (which we handle here explicitly) or through
64 // actions of disappearResult(). It is therefore safe to perform Optional.get() on the results of
67 if (modification.getOperation() == LogicalOperation.DELETE) {
68 if (modification.getChildren().isEmpty()) {
69 return delegate.apply(modification, storeMeta, version);
71 // Delete with children, implies it really is an empty write
72 ret = delegate.applyWrite(modification, emptyNode, storeMeta, version);
73 } else if (modification.getOperation() == LogicalOperation.TOUCH && !storeMeta.isPresent()) {
74 ret = applyTouch(modification, storeMeta, version);
76 // No special handling required here, run normal apply operation
77 ret = delegate.apply(modification, storeMeta, version).get();
80 return disappearResult(modification, ret, storeMeta);
84 void checkApplicable(final ModificationPath path, final NodeModification modification,
85 final Optional<TreeNode> current, final Version version) throws DataValidationFailedException {
86 if (modification.getOperation() == LogicalOperation.TOUCH && !current.isPresent()) {
87 // Structural containers are created as needed, so we pretend this container is here
88 delegate.checkApplicable(path, modification, fakeMeta(FAKE_VERSION), version);
90 delegate.checkApplicable(path, modification, current, version);
94 private Optional<TreeNode> fakeMeta(final Version version) {
95 return Optional.of(TreeNodeFactory.createTreeNode(emptyNode, version));
98 private TreeNode applyTouch(final ModifiedNode modification, final Optional<TreeNode> storeMeta,
99 final Version version) {
100 // Container is not present, let's take care of the 'magically appear' part of our job
101 final Optional<TreeNode> ret = delegate.apply(modification, fakeMeta(version), version);
103 // If the delegate indicated SUBTREE_MODIFIED, account for the fake and report APPEARED
104 if (modification.getModificationType() == ModificationType.SUBTREE_MODIFIED) {
105 modification.resolveModificationType(ModificationType.APPEARED);
110 private static Optional<TreeNode> disappearResult(final ModifiedNode modification, final TreeNode result,
111 final Optional<TreeNode> storeMeta) {
112 // Check if the result is in fact empty before pulling any tricks
113 if (!isEmpty(result)) {
114 return Optional.of(result);
117 // We are pulling the 'disappear' trick, but what we report can be three different things
118 final ModificationType finalType;
119 if (!storeMeta.isPresent()) {
120 // ... there was nothing in the datastore, no change
121 finalType = ModificationType.UNMODIFIED;
122 } else if (modification.getModificationType() == ModificationType.WRITE) {
123 // ... this was an empty write, possibly originally a delete
124 finalType = ModificationType.DELETE;
126 // ... it really disappeared
127 finalType = ModificationType.DISAPPEARED;
129 modification.resolveModificationType(finalType);
130 return Optional.empty();
133 private static boolean isEmpty(final TreeNode treeNode) {
134 final NormalizedNode<?, ?> data = treeNode.getData();
135 if (data instanceof NormalizedNodeContainer) {
136 return ((NormalizedNodeContainer<?, ?, ?>) data).getValue().isEmpty();
138 if (data instanceof OrderedNodeContainer) {
139 return ((OrderedNodeContainer<?>) data).getSize() == 0;
141 throw new IllegalStateException("Unhandled data " + data);