2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
3 * This program and the accompanying materials are made available under the
4 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
5 * and is available at http://www.eclipse.org/legal/epl-v10.html
7 package org.opendaylight.yangtools.yang.data.api;
9 import com.google.common.base.Optional;
10 import com.google.common.base.Preconditions;
11 import com.google.common.collect.ImmutableList;
12 import com.google.common.collect.ImmutableMap;
13 import com.google.common.collect.ImmutableSet;
14 import com.google.common.collect.Iterables;
15 import java.io.IOException;
16 import java.io.ObjectInputStream;
17 import java.io.ObjectOutputStream;
18 import java.io.ObjectStreamException;
19 import java.io.Serializable;
20 import java.lang.reflect.Array;
21 import java.lang.reflect.Field;
22 import java.util.Arrays;
23 import java.util.Collection;
24 import java.util.Collections;
25 import java.util.Iterator;
26 import java.util.List;
28 import java.util.Map.Entry;
29 import java.util.Objects;
31 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
32 import org.opendaylight.yangtools.concepts.Builder;
33 import org.opendaylight.yangtools.concepts.Immutable;
34 import org.opendaylight.yangtools.concepts.Path;
35 import org.opendaylight.yangtools.util.HashCodeBuilder;
36 import org.opendaylight.yangtools.yang.common.QName;
37 import org.opendaylight.yangtools.yang.common.QNameModule;
38 import org.opendaylight.yangtools.yang.data.api.schema.LeafSetEntryNode;
41 * Unique identifier of a particular node instance in the data tree.
44 * Java representation of YANG Built-in type <code>instance-identifier</code>,
45 * which conceptually is XPath expression minimized to uniquely identify element
46 * in data tree which conforms to constraints maintained by YANG Model,
47 * effectively this makes Instance Identifier a path to element in data tree.
49 * Constraints put in YANG specification on instance-identifier allowed it to be
50 * effectively represented in Java and it's evaluation does not require
51 * full-blown XPath processor.
53 * <h3>Path Arguments</h3>
54 * Path to the node represented in instance identifier consists of
55 * {@link PathArgument} which carries necessary information to uniquely identify
56 * node on particular level in the subtree.
59 * <li>{@link NodeIdentifier} - Identifier of node, which has cardinality
60 * <code>0..1</code> in particular subtree in data tree.</li>
61 * <li>{@link NodeIdentifierWithPredicates} - Identifier of node (list item),
62 * which has cardinality <code>0..n</code>.</li>
63 * <li>{@link NodeWithValue} - Identifier of instance <code>leaf</code> node or
64 * <code>leaf-list</code> node.</li>
65 * <li>{@link AugmentationIdentifier} - Identifier of instance of
66 * <code>augmentation</code> node.</li>
70 * @see <a href="http://tools.ietf.org/html/rfc6020#section-9.13">RFC6020</a>
72 public final class YangInstanceIdentifier implements Path<YangInstanceIdentifier>, Immutable, Serializable {
74 * An empty {@link YangInstanceIdentifier}. It corresponds to the path of the conceptual
75 * root of the YANG namespace.
77 public static final YangInstanceIdentifier EMPTY = trustedCreate(Collections.<PathArgument>emptyList());
78 @SuppressWarnings("rawtypes")
79 private static final AtomicReferenceFieldUpdater<YangInstanceIdentifier, ImmutableList> LEGACYPATH_UPDATER =
80 AtomicReferenceFieldUpdater.newUpdater(YangInstanceIdentifier.class, ImmutableList.class, "legacyPath");
81 private static final AtomicReferenceFieldUpdater<YangInstanceIdentifier, String> TOSTRINGCACHE_UPDATER =
82 AtomicReferenceFieldUpdater.newUpdater(YangInstanceIdentifier.class, String.class, "toStringCache");
83 private static final Field PATHARGUMENTS_FIELD;
85 private static final long serialVersionUID = 3L;
86 private final transient Iterable<PathArgument> pathArguments;
87 private final int hash;
89 private transient volatile ImmutableList<PathArgument> legacyPath = null;
90 private transient volatile String toStringCache = null;
95 f = YangInstanceIdentifier.class.getDeclaredField("pathArguments");
96 } catch (NoSuchFieldException | SecurityException e) {
97 throw new ExceptionInInitializerError(e);
99 f.setAccessible(true);
101 PATHARGUMENTS_FIELD = f;
104 private ImmutableList<PathArgument> getLegacyPath() {
105 // Temporary variable saves a volatile read
106 ImmutableList<PathArgument> ret = legacyPath;
108 // We could have used a synchronized block, but the window is quite
109 // small and worst that can happen is duplicate object construction.
110 ret = ImmutableList.copyOf(pathArguments);
111 LEGACYPATH_UPDATER.lazySet(this, ret);
118 * Returns a list of path arguments.
120 * @deprecated Use {@link #getPathArguments()} instead.
121 * @return Immutable list of path arguments.
124 public List<PathArgument> getPath() {
125 return getLegacyPath();
129 * Returns an ordered iteration of path arguments.
131 * @return Immutable iteration of path arguments.
133 public Iterable<PathArgument> getPathArguments() {
134 return pathArguments;
138 * Returns an iterable of path arguments in reverse order. This is useful
139 * when walking up a tree organized this way.
141 * @return Immutable iterable of path arguments in reverse order.
143 public Iterable<PathArgument> getReversePathArguments() {
144 return getLegacyPath().reverse();
148 * Returns the last PathArgument. This is equivalent of iterating
149 * to the last element of the iterable returned by {@link #getPathArguments()}.
151 * @return The last past argument, or null if there are no PathArguments.
153 public PathArgument getLastPathArgument() {
154 return Iterables.getFirst(getReversePathArguments(), null);
157 YangInstanceIdentifier(final Iterable<PathArgument> path, final int hash) {
158 this.pathArguments = Preconditions.checkNotNull(path, "path must not be null.");
162 private static YangInstanceIdentifier trustedCreate(final Iterable<PathArgument> path) {
163 final HashCodeBuilder<PathArgument> hash = new HashCodeBuilder<>();
164 for (PathArgument a : path) {
168 return new YangInstanceIdentifier(path, hash.build());
171 public static YangInstanceIdentifier create(final Iterable<? extends PathArgument> path) {
172 if (Iterables.isEmpty(path)) {
176 return trustedCreate(ImmutableList.copyOf(path));
179 public static YangInstanceIdentifier create(final PathArgument... path) {
180 // We are forcing a copy, since we cannot trust the user
181 return create(Arrays.asList(path));
185 public int hashCode() {
187 * The caching is safe, since the object contract requires
188 * immutability of the object and all objects referenced from this
190 * Used lists, maps are immutable. Path Arguments (elements) are also
191 * immutable, since the PathArgument contract requires immutability.
197 public boolean equals(final Object obj) {
204 if (getClass() != obj.getClass()) {
207 YangInstanceIdentifier other = (YangInstanceIdentifier) obj;
208 if (this.hashCode() != obj.hashCode()) {
211 return Iterables.elementsEqual(pathArguments, other.pathArguments);
215 * Constructs a new Instance Identifier with new {@link NodeIdentifier} added to the end of path arguments
217 * @param name QName of {@link NodeIdentifier}
218 * @return Instance Identifier with additional path argument added to the end.
220 public YangInstanceIdentifier node(final QName name) {
221 return node(new NodeIdentifier(name));
226 * Constructs a new Instance Identifier with new {@link PathArgument} added to the end of path arguments
228 * @param arg Path argument which should be added to the end
229 * @return Instance Identifier with additional path argument added to the end.
231 public YangInstanceIdentifier node(final PathArgument arg) {
232 return new YangInstanceIdentifier(Iterables.concat(pathArguments, Collections.singleton(arg)), HashCodeBuilder.nextHashCode(hash, arg));
236 * Get the relative path from an ancestor. This method attempts to perform
237 * the reverse of concatenating a base (ancestor) and a path.
240 * Ancestor against which the relative path should be calculated
241 * @return This object's relative path from parent, or Optional.absent() if
242 * the specified parent is not in fact an ancestor of this object.
244 public Optional<YangInstanceIdentifier> relativeTo(final YangInstanceIdentifier ancestor) {
245 final Iterator<?> lit = pathArguments.iterator();
246 final Iterator<?> oit = ancestor.pathArguments.iterator();
249 while (oit.hasNext()) {
250 // Ancestor is not really an ancestor
251 if (!lit.hasNext() || !lit.next().equals(oit.next())) {
252 return Optional.absent();
259 return Optional.of(this);
261 if (!lit.hasNext()) {
262 return Optional.of(EMPTY);
264 return Optional.of(trustedCreate(Iterables.skip(pathArguments, common)));
267 private static int hashCode(final Object value) {
272 if (value.getClass().equals(byte[].class)) {
273 return Arrays.hashCode((byte[]) value);
276 if (value.getClass().isArray()) {
278 int length = Array.getLength(value);
279 for (int i = 0; i < length; i++) {
280 hash += Objects.hashCode(Array.get(value, i));
286 return Objects.hashCode(value);
289 // Static factories & helpers
293 * Returns a new InstanceIdentifier with only one path argument of type {@link NodeIdentifier} with supplied QName
295 * @param name QName of first node identifier
296 * @return Instance Identifier with only one path argument of type {@link NodeIdentifier}
298 public static YangInstanceIdentifier of(final QName name) {
299 return create(new NodeIdentifier(name));
304 * Returns new builder for InstanceIdentifier with empty path arguments.
306 * @return new builder for InstanceIdentifier with empty path arguments.
308 public static InstanceIdentifierBuilder builder() {
309 return new YangInstanceIdentifierBuilder();
314 * Returns new builder for InstanceIdentifier with path arguments copied from original instance identifier.
316 * @param origin Instace Identifier from which path arguments are copied.
317 * @return new builder for InstanceIdentifier with path arguments copied from original instance identifier.
319 public static InstanceIdentifierBuilder builder(final YangInstanceIdentifier origin) {
320 return new YangInstanceIdentifierBuilder(origin.getPathArguments(), origin.hashCode());
324 * Path argument / component of InstanceIdentifier
326 * Path argument uniquely identifies node in data tree on particular
329 * This interface itself is used as common parent for actual
330 * path arguments types and should not be implemented by user code.
332 * Path arguments SHOULD contain only minimum of information
333 * required to uniquely identify node on particular subtree level.
335 * For actual path arguments types see:
337 * <li>{@link NodeIdentifier} - Identifier of container or leaf
338 * <li>{@link NodeIdentifierWithPredicates} - Identifier of list entries, which have key defined
339 * <li>{@link AugmentationIdentifier} - Identifier of augmentation
340 * <li>{@link NodeWithValue} - Identifier of leaf-list entry
343 public interface PathArgument extends Comparable<PathArgument>, Immutable, Serializable {
345 * If applicable returns unique QName of data node as defined in YANG
348 * This method may return null, if the corresponding schema node, does
349 * not have QName associated, such as in cases of augmentations.
356 * Return the string representation of this object for use in context
357 * provided by a previous object. This method can be implemented in
358 * terms of {@link #toString()}, but implementations are encourage to
359 * reuse any context already emitted by the previous object.
361 * @param previous Previous path argument
362 * @return String representation
364 String toRelativeString(PathArgument previous);
367 private static abstract class AbstractPathArgument implements PathArgument {
368 private static final long serialVersionUID = -4546547994250849340L;
369 private final QName nodeType;
370 private transient int hashValue;
371 private volatile transient boolean hashGuard = false;
373 protected AbstractPathArgument(final QName nodeType) {
374 this.nodeType = Preconditions.checkNotNull(nodeType);
378 public final QName getNodeType() {
383 public int compareTo(final PathArgument o) {
384 return nodeType.compareTo(o.getNodeType());
387 protected int hashCodeImpl() {
388 return 31 + getNodeType().hashCode();
392 public final int hashCode() {
394 hashValue = hashCodeImpl();
402 public boolean equals(final Object obj) {
406 if (obj == null || this.getClass() != obj.getClass()) {
410 return getNodeType().equals(((AbstractPathArgument)obj).getNodeType());
414 public String toString() {
415 return getNodeType().toString();
419 public String toRelativeString(final PathArgument previous) {
420 if (previous instanceof AbstractPathArgument) {
421 final QNameModule mod = ((AbstractPathArgument)previous).getNodeType().getModule();
422 if (getNodeType().getModule().equals(mod)) {
423 return getNodeType().getLocalName();
427 return getNodeType().toString();
432 * Fluent Builder of Instance Identifier instances
434 public interface InstanceIdentifierBuilder extends Builder<YangInstanceIdentifier> {
436 * Adds {@link NodeIdentifier} with supplied QName to path arguments of resulting instance identifier.
438 * @param nodeType QName of {@link NodeIdentifier} which will be added
439 * @return this builder
441 InstanceIdentifierBuilder node(QName nodeType);
444 * Adds {@link NodeIdentifierWithPredicates} with supplied QName and key values to path arguments of resulting instance identifier.
446 * @param nodeType QName of {@link NodeIdentifierWithPredicates} which will be added
447 * @param keyValues Map of key components and their respective values for {@link NodeIdentifierWithPredicates}
448 * @return this builder
450 InstanceIdentifierBuilder nodeWithKey(QName nodeType, Map<QName, Object> keyValues);
453 * Adds {@link NodeIdentifierWithPredicates} with supplied QName and key, value.
455 * @param nodeType QName of {@link NodeIdentifierWithPredicates} which will be added
456 * @param key QName of key which will be added
457 * @param value value of key which will be added
458 * @return this builder
460 InstanceIdentifierBuilder nodeWithKey(QName nodeType, QName key, Object value);
464 * Builds an {@link YangInstanceIdentifier} with path arguments from this builder
466 * @return {@link YangInstanceIdentifier}
469 YangInstanceIdentifier build();
472 * @deprecated use #build()
475 YangInstanceIdentifier toInstance();
479 * Simple path argument identifying a {@link org.opendaylight.yangtools.yang.data.api.schema.ContainerNode} or
480 * {@link org.opendaylight.yangtools.yang.data.api.schema.LeafNode} leaf in particular subtree.
482 public static final class NodeIdentifier extends AbstractPathArgument {
483 private static final long serialVersionUID = -2255888212390871347L;
485 public NodeIdentifier(final QName node) {
491 * Composite path argument identifying a {@link org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode} leaf
494 public static final class NodeIdentifierWithPredicates extends AbstractPathArgument {
495 private static final long serialVersionUID = -4787195606494761540L;
497 private final Map<QName, Object> keyValues;
499 public NodeIdentifierWithPredicates(final QName node, final Map<QName, Object> keyValues) {
501 this.keyValues = ImmutableMap.copyOf(keyValues);
504 public NodeIdentifierWithPredicates(final QName node, final QName key, final Object value) {
505 this(node, ImmutableMap.of(key, value));
508 public Map<QName, Object> getKeyValues() {
513 protected int hashCodeImpl() {
514 final int prime = 31;
515 int result = super.hashCodeImpl();
516 result = prime * result;
518 for (Entry<QName, Object> entry : keyValues.entrySet()) {
519 result += Objects.hashCode(entry.getKey()) + YangInstanceIdentifier.hashCode(entry.getValue());
525 public boolean equals(final Object obj) {
526 if (!super.equals(obj)) {
530 final Map<QName, Object> otherKeyValues = ((NodeIdentifierWithPredicates) obj).keyValues;
531 if (keyValues.size() != otherKeyValues.size()) {
535 for (Entry<QName, Object> entry : keyValues.entrySet()) {
536 if (!otherKeyValues.containsKey(entry.getKey())
537 || !Objects.deepEquals(entry.getValue(), otherKeyValues.get(entry.getKey()))) {
547 public String toString() {
548 return super.toString() + '[' + keyValues + ']';
552 public String toRelativeString(final PathArgument previous) {
553 return super.toRelativeString(previous) + '[' + keyValues + ']';
558 * Simple path argument identifying a {@link LeafSetEntryNode} leaf
561 public static final class NodeWithValue extends AbstractPathArgument {
562 private static final long serialVersionUID = -3637456085341738431L;
564 private final Object value;
566 public NodeWithValue(final QName node, final Object value) {
571 public Object getValue() {
576 protected int hashCodeImpl() {
577 final int prime = 31;
578 int result = super.hashCodeImpl();
579 result = prime * result + ((value == null) ? 0 : YangInstanceIdentifier.hashCode(value));
584 public boolean equals(final Object obj) {
585 if (!super.equals(obj)) {
588 final NodeWithValue other = (NodeWithValue) obj;
589 return Objects.deepEquals(value, other.value);
593 public String toString() {
594 return super.toString() + '[' + value + ']';
598 public String toRelativeString(final PathArgument previous) {
599 return super.toRelativeString(previous) + '[' + value + ']';
604 * Composite path argument identifying a {@link org.opendaylight.yangtools.yang.data.api.schema.AugmentationNode} node in
605 * particular subtree.
607 * Augmentation is uniquely identified by set of all possible child nodes.
609 * to identify instance of augmentation,
610 * since RFC6020 states that <code>augment</code> that augment
611 * statement must not add multiple nodes from same namespace
612 * / module to the target node.
615 * @see <a href="http://tools.ietf.org/html/rfc6020#section-7.15">RFC6020</a>
617 public static final class AugmentationIdentifier implements PathArgument {
618 private static final long serialVersionUID = -8122335594681936939L;
619 private final ImmutableSet<QName> childNames;
622 public QName getNodeType() {
623 // This should rather throw exception than return always null
624 throw new UnsupportedOperationException("Augmentation node has no QName");
629 * Construct new augmentation identifier using supplied set of possible
633 * Set of possible child nodes.
635 public AugmentationIdentifier(final Set<QName> childNames) {
636 this.childNames = ImmutableSet.copyOf(childNames);
640 * Returns set of all possible child nodes
642 * @return set of all possible child nodes.
644 public Set<QName> getPossibleChildNames() {
649 public String toString() {
650 final StringBuilder sb = new StringBuilder("AugmentationIdentifier{");
651 sb.append("childNames=").append(childNames).append('}');
652 return sb.toString();
656 public String toRelativeString(final PathArgument previous) {
661 public boolean equals(final Object o) {
665 if (!(o instanceof AugmentationIdentifier)) {
669 AugmentationIdentifier that = (AugmentationIdentifier) o;
670 return childNames.equals(that.childNames);
674 public int hashCode() {
675 return childNames.hashCode();
679 public int compareTo(final PathArgument o) {
680 if (!(o instanceof AugmentationIdentifier)) {
683 AugmentationIdentifier other = (AugmentationIdentifier) o;
684 Set<QName> otherChildNames = other.getPossibleChildNames();
685 int thisSize = childNames.size();
686 int otherSize = otherChildNames.size();
687 if (thisSize == otherSize) {
688 Iterator<QName> otherIterator = otherChildNames.iterator();
689 for (QName name : childNames) {
690 int c = name.compareTo(otherIterator.next());
696 } else if (thisSize < otherSize) {
705 public boolean contains(final YangInstanceIdentifier other) {
706 Preconditions.checkArgument(other != null, "other should not be null");
708 final Iterator<?> lit = pathArguments.iterator();
709 final Iterator<?> oit = other.pathArguments.iterator();
711 while (lit.hasNext()) {
712 if (!oit.hasNext()) {
716 if (!lit.next().equals(oit.next())) {
725 public String toString() {
727 * The toStringCache is safe, since the object contract requires
728 * immutability of the object and all objects referenced from this
730 * Used lists, maps are immutable. Path Arguments (elements) are also
731 * immutable, since the PathArgument contract requires immutability.
732 * The cache is thread-safe - if multiple computations occurs at the
733 * same time, cache will be overwritten with same result.
735 String ret = toStringCache;
737 final StringBuilder builder = new StringBuilder("/");
738 PathArgument prev = null;
739 for (PathArgument argument : getPathArguments()) {
743 builder.append(argument.toRelativeString(prev));
747 ret = builder.toString();
748 TOSTRINGCACHE_UPDATER.lazySet(this, ret);
753 private void readObject(final ObjectInputStream inputStream) throws IOException, ClassNotFoundException {
754 inputStream.defaultReadObject();
755 legacyPath = ImmutableList.copyOf((Collection<PathArgument>)inputStream.readObject());
758 PATHARGUMENTS_FIELD.set(this, legacyPath);
759 } catch (IllegalArgumentException | IllegalAccessException e) {
760 throw new IOException(e);
764 private Object readResolve() throws ObjectStreamException {
765 return legacyPath.isEmpty() ? EMPTY : this;
768 private void writeObject(final ObjectOutputStream outputStream) throws IOException {
770 * This may look strange, but what we are doing here is side-stepping the fact
771 * that pathArguments is not generally serializable. We are forcing instantiation
772 * of the legacy path, which is an ImmutableList (thus Serializable) and write
773 * it out. The read path does the opposite -- it reads the legacyPath and then
774 * uses invocation API to set the field.
776 ImmutableList<PathArgument> pathArguments = getLegacyPath();
777 outputStream.defaultWriteObject();
778 outputStream.writeObject(pathArguments);