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.yangtools.yang.parser.stmt.reactor;
10 import static com.google.common.base.Verify.verify;
11 import static java.util.Objects.requireNonNull;
13 import com.google.common.base.VerifyException;
14 import com.google.common.collect.ImmutableList;
15 import com.google.common.collect.Streams;
16 import java.util.ArrayList;
17 import java.util.Collection;
18 import java.util.Collections;
19 import java.util.HashMap;
20 import java.util.Iterator;
21 import java.util.List;
23 import java.util.Objects;
24 import java.util.Optional;
25 import java.util.stream.Collectors;
26 import java.util.stream.Stream;
27 import org.eclipse.jdt.annotation.NonNull;
28 import org.eclipse.jdt.annotation.Nullable;
29 import org.opendaylight.yangtools.concepts.Immutable;
30 import org.opendaylight.yangtools.yang.common.QName;
31 import org.opendaylight.yangtools.yang.common.QNameModule;
32 import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
33 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
34 import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
35 import org.opendaylight.yangtools.yang.model.api.stmt.SchemaTreeEffectiveStatement;
36 import org.opendaylight.yangtools.yang.parser.spi.SchemaTreeNamespace;
37 import org.opendaylight.yangtools.yang.parser.spi.meta.CopyType;
38 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStatementState;
39 import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
40 import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.OnDemandSchemaTreeStorageNode;
41 import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.StorageNodeType;
42 import org.opendaylight.yangtools.yang.parser.spi.meta.StatementFactory;
43 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
44 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
45 import org.opendaylight.yangtools.yang.parser.spi.source.StatementSourceReference;
46 import org.slf4j.Logger;
47 import org.slf4j.LoggerFactory;
50 * A statement which has been inferred to exist. Functionally it is equivalent to a SubstatementContext, but it is not
51 * backed by a declaration (and declared statements). It is backed by a prototype StatementContextBase and has only
52 * effective substatements, which are either transformed from that prototype or added by inference.
54 final class InferredStatementContext<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
55 extends StatementContextBase<A, D, E> implements OnDemandSchemaTreeStorageNode {
56 // An effective copy view, with enough information to decide what to do next
57 private static final class EffectiveCopy implements Immutable {
59 private final ReactorStmtCtx<?, ?, ?> orig;
60 // Effective view, if the statement is to be reused it equals to orig
61 private final ReactorStmtCtx<?, ?, ?> copy;
63 EffectiveCopy(final ReactorStmtCtx<?, ?, ?> orig, final ReactorStmtCtx<?, ?, ?> copy) {
64 this.orig = requireNonNull(orig);
65 this.copy = requireNonNull(copy);
72 ReactorStmtCtx<?, ?, ?> toChildContext(final @NonNull InferredStatementContext<?, ?, ?> parent) {
73 return isReused() ? orig.replicaAsChildOf(parent) : copy;
76 ReactorStmtCtx<?, ?, ?> toReusedChild(final @NonNull InferredStatementContext<?, ?, ?> parent) {
77 verify(isReused(), "Attempted to discard copy %s", copy);
78 return orig.replicaAsChildOf(parent);
82 private static final Logger LOG = LoggerFactory.getLogger(InferredStatementContext.class);
84 // Sentinel objects for 'substatements', String is a good enough type
85 private static final @NonNull String REUSED_SUBSTATEMENTS = "reused";
86 private static final @NonNull String SWEPT_SUBSTATEMENTS = "swept";
88 private final @NonNull StatementContextBase<A, D, E> prototype;
89 private final @NonNull StatementContextBase<?, ?, ?> parent;
90 private final @NonNull StmtContext<A, D, E> originalCtx;
91 private final QNameModule targetModule;
92 private final A argument;
95 * Effective substatements, lazily materialized. This field can have four states:
97 * <li>it can be {@code null}, in which case no materialization has taken place</li>
98 * <li>it can be a {@link HashMap}, in which case partial materialization has taken place</li>
99 * <li>it can be a {@link List}, in which case full materialization has taken place</li>
100 * <li>it can be {@link SWEPT_SUBSTATEMENTS}, in which case materialized state is no longer available</li>
103 private Object substatements;
105 private InferredStatementContext(final InferredStatementContext<A, D, E> original,
106 final StatementContextBase<?, ?, ?> parent) {
108 this.parent = requireNonNull(parent);
109 this.targetModule = original.targetModule;
110 this.prototype = original.prototype;
111 this.originalCtx = original.originalCtx;
112 this.argument = original.argument;
113 // Substatements are initialized here
114 this.substatements = ImmutableList.of();
117 InferredStatementContext(final StatementContextBase<?, ?, ?> parent, final StatementContextBase<A, D, E> prototype,
118 final CopyType myCopyType, final CopyType childCopyType, final QNameModule targetModule) {
119 super(prototype, myCopyType, childCopyType);
120 this.parent = requireNonNull(parent);
121 this.prototype = requireNonNull(prototype);
122 this.argument = targetModule == null ? prototype.argument()
123 : prototype.definition().adaptArgumentValue(prototype, targetModule);
124 this.targetModule = targetModule;
125 this.originalCtx = prototype.getOriginalCtx().orElse(prototype);
127 // Mark prototype as blocking statement cleanup
132 public Collection<? extends StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements() {
133 return ImmutableList.of();
137 public Collection<? extends Mutable<?, ?, ?>> mutableEffectiveSubstatements() {
138 return mutableEffectiveSubstatements(ensureEffectiveSubstatements());
142 public Iterable<? extends StmtContext<?, ?, ?>> allSubstatements() {
143 // No need to concat with declared
144 return effectiveSubstatements();
148 public Stream<? extends StmtContext<?, ?, ?>> allSubstatementsStream() {
149 // No need to concat with declared
150 return effectiveSubstatements().stream();
154 public StatementSourceReference sourceReference() {
155 return originalCtx.sourceReference();
159 public String rawArgument() {
160 return originalCtx.rawArgument();
164 public Optional<StmtContext<A, D, E>> getOriginalCtx() {
165 return Optional.of(originalCtx);
169 public Optional<StmtContext<A, D, E>> getPreviousCopyCtx() {
170 return Optional.of(prototype);
174 public D declared() {
176 * Share original instance of declared statement between all effective statements which have been copied or
177 * derived from this original declared statement.
179 return originalCtx.declared();
183 public void removeStatementFromEffectiveSubstatements(final StatementDefinition statementDef) {
184 substatements = removeStatementFromEffectiveSubstatements(ensureEffectiveSubstatements(), statementDef);
188 public void removeStatementFromEffectiveSubstatements(final StatementDefinition statementDef,
189 final String statementArg) {
190 substatements = removeStatementFromEffectiveSubstatements(ensureEffectiveSubstatements(), statementDef,
195 public void addEffectiveSubstatement(final Mutable<?, ?, ?> substatement) {
196 substatements = addEffectiveSubstatement(ensureEffectiveSubstatements(), substatement);
200 void addEffectiveSubstatementsImpl(final Collection<? extends Mutable<?, ?, ?>> statements) {
201 substatements = addEffectiveSubstatementsImpl(ensureEffectiveSubstatements(), statements);
205 InferredStatementContext<A, D, E> reparent(final StatementContextBase<?, ?, ?> newParent) {
206 return new InferredStatementContext<>(this, newParent);
210 E createEffective(final StatementFactory<A, D, E> factory) {
211 // If we have not materialized we do not have a difference in effective substatements, hence we can forward
212 // towards the source of the statement.
213 accessSubstatements();
214 return substatements == null ? tryToReusePrototype(factory) : super.createEffective(factory);
217 private @NonNull E tryToReusePrototype(final StatementFactory<A, D, E> factory) {
218 final E origEffective = prototype.buildEffective();
219 final Collection<? extends @NonNull EffectiveStatement<?, ?>> origSubstatements =
220 origEffective.effectiveSubstatements();
222 // First check if we can reuse the entire prototype
223 if (!factory.canReuseCurrent(this, prototype, origSubstatements)) {
224 return internAlongCopyAxis(factory, tryToReuseSubstatements(factory, origEffective));
227 // We can reuse this statement let's see if all statements agree...
228 // ... no substatements to deal with, we can freely reuse the original
229 if (origSubstatements.isEmpty()) {
230 LOG.debug("Reusing empty: {}", origEffective);
231 substatements = ImmutableList.of();
233 return origEffective;
236 // ... all are context independent, reuse the original
237 if (allSubstatementsContextIndependent()) {
238 LOG.debug("Reusing context-independent: {}", origEffective);
239 substatements = noRefs() ? REUSED_SUBSTATEMENTS : reusePrototypeReplicas();
241 return origEffective;
244 // ... copy-sensitive check
245 final List<EffectiveCopy> declCopy = prototype.streamDeclared()
246 .map(sub -> effectiveCopy((ReactorStmtCtx<?, ?, ?>) sub))
247 .filter(Objects::nonNull)
248 .collect(Collectors.toUnmodifiableList());
249 final List<EffectiveCopy> effCopy = prototype.streamEffective()
250 .map(sub -> effectiveCopy((ReactorStmtCtx<?, ?, ?>) sub))
251 .filter(Objects::nonNull)
252 .collect(Collectors.toUnmodifiableList());
254 // ... are any copy-sensitive?
255 if (allReused(declCopy) && allReused(effCopy)) {
256 LOG.debug("Reusing after substatement check: {}", origEffective);
257 substatements = noRefs() ? REUSED_SUBSTATEMENTS
258 : reusePrototypeReplicas(Streams.concat(declCopy.stream(), effCopy.stream())
259 .map(copy -> copy.toReusedChild(this)));
261 return origEffective;
264 // *sigh*, ok, heavy lifting through a shallow copy
265 final List<ReactorStmtCtx<?, ?, ?>> declared = declCopy.stream()
266 .map(copy -> copy.toChildContext(this))
267 .collect(ImmutableList.toImmutableList());
268 final List<ReactorStmtCtx<?, ?, ?>> effective = effCopy.stream()
269 .map(copy -> copy.toChildContext(this))
270 .collect(ImmutableList.toImmutableList());
271 substatements = declared.isEmpty() ? effective
272 : Streams.concat(declared.stream(), effective.stream()).collect(ImmutableList.toImmutableList());
275 // Values are the effective copies, hence this efficiently deals with recursion.
276 return internAlongCopyAxis(factory, factory.createEffective(this, declared.stream(), effective.stream()));
279 private @NonNull E tryToReuseSubstatements(final StatementFactory<A, D, E> factory, final @NonNull E original) {
280 if (allSubstatementsContextIndependent()) {
281 LOG.debug("Reusing substatements of: {}", prototype);
282 substatements = noRefs() ? REUSED_SUBSTATEMENTS : reusePrototypeReplicas();
284 return factory.copyEffective(this, original);
287 // Fall back to full instantiation, which populates our substatements. Then check if we should be reusing
288 // the substatement list, as this operation turned out to not affect them.
289 final E effective = super.createEffective(factory);
290 // Since we have forced instantiation to deal with this case, we also need to reset the 'modified' flag
293 if (sameSubstatements(original.effectiveSubstatements(), effective)) {
294 LOG.debug("Reusing unchanged substatements of: {}", prototype);
295 return factory.copyEffective(this, original);
300 private @NonNull E internAlongCopyAxis(final StatementFactory<A, D, E> factory, final @NonNull E stmt) {
302 final EffectiveStatementState state = factory.extractEffectiveState(stmt);
304 return prototype.unmodifiedEffectiveSource().attachEffectiveCopy(state, stmt);
310 private List<ReactorStmtCtx<?, ?, ?>> reusePrototypeReplicas() {
311 return reusePrototypeReplicas(Streams.concat(prototype.streamDeclared(), prototype.streamEffective()));
314 private List<ReactorStmtCtx<?, ?, ?>> reusePrototypeReplicas(final Stream<StmtContext<?, ?, ?>> stream) {
317 final ReplicaStatementContext<?, ?, ?> ret = ((ReactorStmtCtx<?, ?, ?>) stmt).replicaAsChildOf(this);
318 ret.buildEffective();
321 .collect(Collectors.toUnmodifiableList());
324 private static boolean sameSubstatements(final Collection<?> original, final EffectiveStatement<?, ?> effective) {
325 final Collection<?> copied = effective.effectiveSubstatements();
326 if (copied != effective.effectiveSubstatements() || original.size() != copied.size()) {
327 // Do not bother if result is treating substatements as transient
331 final Iterator<?> oit = original.iterator();
332 final Iterator<?> cit = copied.iterator();
333 while (oit.hasNext()) {
334 verify(cit.hasNext());
335 // Identity comparison on purpose to side-step whatever equality there might be. We want to reuse instances
337 if (oit.next() != cit.next()) {
341 verify(!cit.hasNext());
345 private static boolean allReused(final List<EffectiveCopy> entries) {
346 return entries.stream().allMatch(EffectiveCopy::isReused);
350 ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource() {
351 return isModified() ? this : prototype.unmodifiedEffectiveSource();
355 boolean hasEmptySubstatements() {
356 if (substatements == null) {
357 return prototype.hasEmptySubstatements();
359 return substatements instanceof HashMap ? false : ((List<?>) substatements).isEmpty();
363 boolean noSensitiveSubstatements() {
364 accessSubstatements();
365 if (substatements == null) {
366 // No difference, defer to prototype
367 return prototype.allSubstatementsContextIndependent();
369 if (substatements instanceof List) {
370 // Fully materialized, walk all statements
371 return noSensitiveSubstatements(castEffective(substatements));
374 // Partially-materialized. This case has three distinct outcomes:
375 // - prototype does not have a sensitive statement (1)
376 // - protype has a sensitive substatement, and
377 // - we have not marked is as unsupported (2)
378 // - we have marked it as unsupported (3)
380 // Determining the outcome between (2) and (3) is a bother, this check errs on the side of false negative side
381 // and treats (3) as (2) -- i.e. even if we marked a sensitive statement as unsupported, we still consider it
382 // as affecting the result.
383 return prototype.allSubstatementsContextIndependent()
384 && noSensitiveSubstatements(castMaterialized(substatements).values());
388 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
389 final @NonNull Class<Z> type) {
390 if (substatements instanceof List) {
391 return super.findSubstatementArgumentImpl(type);
394 final Optional<X> templateArg = prototype.findSubstatementArgument(type);
395 if (templateArg.isEmpty()) {
398 if (SchemaTreeEffectiveStatement.class.isAssignableFrom(type)) {
399 // X is known to be QName
400 return (Optional<X>) templateArg.map(template -> ((QName) template).bindTo(targetModule));
406 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
407 return substatements instanceof List ? super.hasSubstatementImpl(type)
408 // We do not allow deletion of partially-materialized statements, hence this is accurate
409 : prototype.hasSubstatement(type);
413 public <Y extends DeclaredStatement<QName>, Z extends SchemaTreeEffectiveStatement<Y>>
414 StmtContext<QName, Y, Z> requestSchemaTreeChild(final QName qname) {
415 if (substatements instanceof List) {
416 // We have performed materialization, hence we have triggered creation of all our schema tree child
421 final QName templateQName = qname.bindTo(StmtContextUtils.getRootModuleQName(prototype));
422 LOG.debug("Materializing child {} from {}", qname, templateQName);
424 final StmtContext<?, ?, ?> template;
425 if (prototype instanceof InferredStatementContext) {
426 // Note: we need to access namespace here, as the target statement may have already been populated, in which
427 // case we want to obtain the statement in local namespace storage.
428 template = (StmtContext) ((InferredStatementContext<?, ?, ?>) prototype).getFromNamespace(
429 SchemaTreeNamespace.class, templateQName);
431 template = prototype.allSubstatementsStream()
432 .filter(stmt -> stmt.producesEffective(SchemaTreeEffectiveStatement.class)
433 && templateQName.equals(stmt.argument()))
438 if (template == null) {
439 // We do not have a template, this child does not exist. It may be added later, but that is someone else's
441 LOG.debug("Child {} does not have a template", qname);
445 @SuppressWarnings("unchecked")
446 final Mutable<QName, Y, Z> ret = (Mutable<QName, Y, Z>) copySubstatement((Mutable<?, ?, ?>) template)
448 () -> new InferenceException(this, "Failed to materialize child %s template %s", qname, template));
449 ensureCompletedPhase(ret);
450 addMaterialized(template, ret);
452 LOG.debug("Child {} materialized", qname);
456 // Instantiate this statement's effective substatements. Note this method has side-effects in namespaces and overall
457 // BuildGlobalContext, hence it must be called at most once.
458 private List<ReactorStmtCtx<?, ?, ?>> ensureEffectiveSubstatements() {
459 accessSubstatements();
460 return substatements instanceof List ? castEffective(substatements)
461 : initializeSubstatements(castMaterialized(substatements));
465 Iterator<ReactorStmtCtx<?, ?, ?>> effectiveChildrenToComplete() {
466 // When we have not initialized, there are no statements to catch up: we will catch up when we are copying
467 // from prototype (which is already at ModelProcessingPhase.EFFECTIVE_MODEL).
468 if (substatements == null) {
469 return Collections.emptyIterator();
471 accessSubstatements();
472 if (substatements instanceof HashMap) {
473 return castMaterialized(substatements).values().iterator();
475 return castEffective(substatements).iterator();
480 Stream<? extends @NonNull StmtContext<?, ?, ?>> streamDeclared() {
481 return Stream.empty();
485 Stream<? extends @NonNull StmtContext<?, ?, ?>> streamEffective() {
486 return ensureEffectiveSubstatements().stream().filter(StmtContext::isSupportedToBuildEffective);
489 private void accessSubstatements() {
490 if (substatements instanceof String) {
491 throw new VerifyException("Access to " + substatements + " substatements of " + this);
496 void markNoParentRef() {
497 final Object local = substatements;
499 markNoParentRef(castEffective(local));
504 int sweepSubstatements() {
505 final Object local = substatements;
506 substatements = SWEPT_SUBSTATEMENTS;
508 if (local instanceof List) {
509 final List<ReactorStmtCtx<?, ?, ?>> list = castEffective(local);
511 count = countUnswept(list);
516 private List<ReactorStmtCtx<?, ?, ?>> initializeSubstatements(
517 final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree) {
518 final Collection<? extends StatementContextBase<?, ?, ?>> declared = prototype.mutableDeclaredSubstatements();
519 final Collection<? extends Mutable<?, ?, ?>> effective = prototype.mutableEffectiveSubstatements();
521 final List<Mutable<?, ?, ?>> buffer = new ArrayList<>(declared.size() + effective.size());
522 for (final Mutable<?, ?, ?> stmtContext : declared) {
523 if (stmtContext.isSupportedByFeatures()) {
524 copySubstatement(stmtContext, buffer, materializedSchemaTree);
527 for (final Mutable<?, ?, ?> stmtContext : effective) {
528 copySubstatement(stmtContext, buffer, materializedSchemaTree);
531 final List<ReactorStmtCtx<?, ?, ?>> ret = beforeAddEffectiveStatementUnsafe(ImmutableList.of(), buffer.size());
532 ret.addAll((Collection) buffer);
541 // Statement copy mess starts here. As it turns out, it's not that much of a mess, but it does make your head spin
542 // sometimes. Tread softly because you tread on my dreams.
545 private EffectiveCopy effectiveCopy(final ReactorStmtCtx<?, ?, ?> stmt) {
546 final ReactorStmtCtx<?, ?, ?> effective = stmt.asEffectiveChildOf(this, childCopyType(), targetModule);
547 return effective == null ? null : new EffectiveCopy(stmt, effective);
550 private void copySubstatement(final Mutable<?, ?, ?> substatement, final Collection<Mutable<?, ?, ?>> buffer,
551 final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree) {
552 // Consult materialized substatements. We are in a copy operation and will end up throwing materialized
553 // statements away -- hence we do not perform Map.remove() to save ourselves a mutation operation.
555 // We could also perform a Map.containsKey() and perform a bulk add, but that would mean the statement order
556 // against parent would change -- and we certainly do not want that to happen.
557 final ReactorStmtCtx<?, ?, ?> materialized = findMaterialized(materializedSchemaTree, substatement);
558 if (materialized == null) {
559 copySubstatement(substatement).ifPresent(copy -> {
560 ensureCompletedPhase(copy);
564 buffer.add(materialized);
568 private Optional<? extends Mutable<?, ?, ?>> copySubstatement(final Mutable<?, ?, ?> substatement) {
569 return substatement.copyAsChildOf(this, childCopyType(), targetModule);
572 private void addMaterialized(final StmtContext<?, ?, ?> template, final Mutable<?, ?, ?> copy) {
573 final HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree;
574 if (substatements == null) {
575 // Lazy initialization of backing map. We do not expect this to be used often or multiple times -- each hit
576 // here means an inference along schema tree, such as deviate/augment. HashMap requires power-of-two and
577 // defaults to 0.75 load factor -- we therefore size it to 4, i.e. next two inserts will not cause a
578 // resizing operation.
579 materializedSchemaTree = new HashMap<>(4);
580 substatements = materializedSchemaTree;
583 verify(substatements instanceof HashMap, "Unexpected substatements %s", substatements);
584 materializedSchemaTree = castMaterialized(substatements);
587 final StmtContext<?, ?, ?> existing = materializedSchemaTree.put(template,
588 (StatementContextBase<?, ?, ?>) copy);
589 if (existing != null) {
590 throw new VerifyException(
591 "Unexpected duplicate request for " + copy.argument() + " previous result was " + existing);
595 private static @Nullable ReactorStmtCtx<?, ?, ?> findMaterialized(
596 final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree,
597 final StmtContext<?, ?, ?> template) {
598 return materializedSchemaTree == null ? null : materializedSchemaTree.get(template);
601 @SuppressWarnings("unchecked")
602 private static List<ReactorStmtCtx<?, ?, ?>> castEffective(final Object substatements) {
603 return (List<ReactorStmtCtx<?, ?, ?>>) substatements;
606 @SuppressWarnings("unchecked")
607 private static HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> castMaterialized(final Object substatements) {
608 return (HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>>) substatements;
611 // Statement copy mess ends here
614 * KEEP THINGS ORGANIZED!
616 * below methods exist in the same form in SubstatementContext. If any adjustment is made here, make sure it is
617 * properly updated there.
620 public A argument() {
625 public StatementContextBase<?, ?, ?> getParentContext() {
630 public StorageNodeType getStorageNodeType() {
631 return StorageNodeType.STATEMENT_LOCAL;
635 public StatementContextBase<?, ?, ?> getParentNamespaceStorage() {
640 public RootStatementContext<?, ?, ?> getRoot() {
641 return parent.getRoot();
645 public EffectiveConfig effectiveConfig() {
646 return effectiveConfig(parent);
650 protected boolean isIgnoringIfFeatures() {
651 return isIgnoringIfFeatures(parent);
655 protected boolean isIgnoringConfig() {
656 return isIgnoringConfig(parent);
660 protected boolean isParentSupportedByFeatures() {
661 return parent.isSupportedByFeatures();