2 * Copyright (c) 2020 PANTHEON.tech, s.r.o. 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.mdsal.dom.spi.query;
10 import static com.google.common.base.Preconditions.checkArgument;
12 import java.util.AbstractMap.SimpleImmutableEntry;
13 import java.util.ArrayDeque;
14 import java.util.ArrayList;
15 import java.util.Deque;
16 import java.util.List;
17 import java.util.Map.Entry;
18 import java.util.Optional;
19 import org.eclipse.jdt.annotation.NonNullByDefault;
20 import org.opendaylight.mdsal.dom.api.query.DOMQuery;
21 import org.opendaylight.mdsal.dom.api.query.DOMQueryPredicate;
22 import org.opendaylight.mdsal.dom.api.query.DOMQueryResult;
23 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
24 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
25 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
26 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
27 import org.opendaylight.yangtools.yang.data.api.schema.MapNode;
28 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
29 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodes;
32 public final class DOMQueryEvaluator {
33 private DOMQueryEvaluator() {
38 * Evaluate {@link DOMQuery} on its data element. The element is expected to correspond to
39 * {@link DOMQuery#getRoot()}.
41 * @param query Query to execute
42 * @param queryRoot Query root object
43 * @return Result of evaluation
44 * @throws NullPointerException if any argument is null
46 public static DOMQueryResult evaluateOn(final DOMQuery query, final NormalizedNode<?, ?> queryRoot) {
47 final YangInstanceIdentifier path = query.getSelect();
48 return path.isEmpty() ? evalSingle(queryRoot, query) : evalPath(queryRoot, query);
52 * Evaluate {@link DOMQuery} on a conceptual root. The element is expected to correspond to the conceptual data tree
53 * root. This method will first find the {@link DOMQuery#getRoot()} and then defer to
54 * {@link #evaluateOn(DOMQuery, NormalizedNode)}.
56 * @param query Query to execute
57 * @param root Conceptual root object
58 * @return Result of evaluation
59 * @throws NullPointerException if any argument is null
61 public static DOMQueryResult evaluateOnRoot(final DOMQuery query, final NormalizedNode<?, ?> root) {
62 NormalizedNode<?, ?> evalRoot = root;
63 for (PathArgument arg : query.getRoot().getPathArguments()) {
64 final Optional<NormalizedNode<?, ?>> next = NormalizedNodes.findNode(root, arg);
66 return DOMQueryResult.of();
68 evalRoot = next.orElseThrow();
70 return evaluateOn(query, evalRoot);
73 private static DOMQueryResult evalSingle(final NormalizedNode<?, ?> data, final DOMQuery query) {
74 return matches(data, query) ? DOMQueryResult.of()
75 : DOMQueryResult.of(new SimpleImmutableEntry<>(query.getRoot(), data));
78 private static DOMQueryResult evalPath(final NormalizedNode<?, ?> queryRoot, final DOMQuery query) {
79 // FIXME: this is eager evaluation, we should be doing lazy traversal
80 final List<Entry<YangInstanceIdentifier, NormalizedNode<?, ?>>> result = new ArrayList<>();
81 evalPath(result, new ArrayDeque<>(query.getRoot().getPathArguments()),
82 new ArrayDeque<>(query.getSelect().getPathArguments()), queryRoot, query);
83 return DOMQueryResult.of(result);
86 private static void evalPath(final List<Entry<YangInstanceIdentifier, NormalizedNode<?,?>>> result,
87 final Deque<PathArgument> path, final ArrayDeque<PathArgument> remaining,
88 final NormalizedNode<?, ?> data, final DOMQuery query) {
89 final PathArgument next = remaining.poll();
91 if (matches(data, query)) {
92 result.add(new SimpleImmutableEntry<>(YangInstanceIdentifier.create(path), data));
97 if (data instanceof MapNode && next instanceof NodeIdentifier) {
98 checkArgument(data.getIdentifier().equals(next), "Unexpected step %s", next);
99 for (MapEntryNode child : ((MapNode) data).getValue()) {
100 evalChild(result, path, remaining, query, child);
103 NormalizedNodes.getDirectChild(data, next).ifPresent(
104 child -> evalChild(result, path, remaining, query, child));
106 remaining.push(next);
109 private static void evalChild(final List<Entry<YangInstanceIdentifier, NormalizedNode<?,?>>> result,
110 final Deque<PathArgument> path, final ArrayDeque<PathArgument> remaining, final DOMQuery query,
111 final NormalizedNode<?, ?> child) {
112 path.addLast(child.getIdentifier());
113 evalPath(result, path, remaining, child, query);
117 private static boolean matches(final NormalizedNode<?, ?> data, final DOMQuery query) {
118 for (DOMQueryPredicate pred : query.getPredicates()) {
119 // Okay, now we need to deal with predicates, but do it in a smart fashion, so we do not end up iterating
120 // all over the place. Typically we will be matching just a leaf.
121 final YangInstanceIdentifier path = pred.getPath();
122 final Optional<NormalizedNode<?, ?>> node;
123 if (path.coerceParent().isEmpty()) {
124 node = NormalizedNodes.getDirectChild(data, path.getLastPathArgument());
126 node = NormalizedNodes.findNode(data, path);
129 if (!pred.test(node.orElse(null))) {