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.parser.spi.meta;
10 import static com.google.common.base.Preconditions.checkArgument;
11 import static java.util.Objects.requireNonNull;
13 import com.google.common.annotations.Beta;
14 import com.google.common.base.VerifyException;
15 import java.util.Collection;
16 import java.util.Optional;
17 import org.eclipse.jdt.annotation.NonNull;
18 import org.eclipse.jdt.annotation.Nullable;
19 import org.opendaylight.yangtools.concepts.Immutable;
20 import org.opendaylight.yangtools.yang.common.QName;
21 import org.opendaylight.yangtools.yang.common.QNameModule;
22 import org.opendaylight.yangtools.yang.model.api.meta.ArgumentDefinition;
23 import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
24 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
25 import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
26 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;
27 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
28 import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
31 * Support for processing concrete YANG statement.
34 * This interface is intended to be implemented by developers, which want to introduce support of statement to parser.
35 * Consider subclassing {@link AbstractStatementSupport} for easier implementation of this interface.
37 * @param <A> Argument type
38 * @param <D> Declared Statement representation
39 * @param <E> Effective Statement representation
41 public abstract class StatementSupport<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
42 implements StatementDefinition, StatementFactory<A, D, E> {
44 * A baseline class for implementing the {@link StatementFactory#canReuseCurrent(Current, Current, Collection)}
45 * contract in a manner which is consistent with a statement's {@link CopyPolicy}.
47 * @param <A> Argument type
48 * @param <D> Declared Statement representation
50 public abstract static class StatementPolicy<A, D extends DeclaredStatement<A>> implements Immutable {
51 final @NonNull CopyPolicy copyPolicy;
53 StatementPolicy(final CopyPolicy copyPolicy) {
54 this.copyPolicy = requireNonNull(copyPolicy);
58 * Return a {@link StatementPolicy} for {@link CopyPolicy#CONTEXT_INDEPENDENT}.
60 * @param <A> Argument type
61 * @param <D> Declared Statement representation
62 * @return Context-independent policy
64 @SuppressWarnings("unchecked")
65 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> contextIndependent() {
66 return (StatementPolicy<A, D>) EqualSemantics.CONTEXT_INDEPENDENT;
70 * Return a {@link StatementPolicy} for {@link CopyPolicy#EXACT_REPLICA}.
72 * @param <A> Argument type
73 * @param <D> Declared Statement representation
74 * @return Exact-replica policy
76 @SuppressWarnings("unchecked")
77 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> exactReplica() {
78 return (StatementPolicy<A, D>) EqualSemantics.EXACT_REPLICA;
82 * Return a {@link StatementPolicy} for {@link CopyPolicy#IGNORE}.
84 * @param <A> Argument type
85 * @param <D> Declared Statement representation
86 * @return Ignoring policy
88 @SuppressWarnings("unchecked")
89 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> ignore() {
90 return (StatementPolicy<A, D>) AlwaysFail.IGNORE;
94 * Return a {@link StatementPolicy} for {@link CopyPolicy#REJECT}.
96 * @param <A> Argument type
97 * @param <D> Declared Statement representation
98 * @return Rejecting statement policy
100 @SuppressWarnings("unchecked")
101 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> reject() {
102 return (StatementPolicy<A, D>) AlwaysFail.REJECT;
106 * Return a {@link StatementPolicy} for {@link CopyPolicy#DECLARED_COPY}, deferring to a
107 * {@link StatementEquality} for individual decisions.
109 * @param <A> Argument type
110 * @param <D> Declared Statement representation
111 * @param equality {@link StatementEquality} to apply to effective statements
112 * @return Equality-based statement policy
114 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> copyDeclared(
115 final @NonNull StatementEquality<A, D> equality) {
116 return new EqualSemantics<>(equality);
120 * Return a {@link StatementPolicy} for {@link CopyPolicy#DECLARED_COPY}, always performing a copy operation.
122 * @param <A> Argument type
123 * @param <D> Declared Statement representation
124 * @return Rejecting statement policy
126 @SuppressWarnings("unchecked")
127 public static final <A, D extends DeclaredStatement<A>> @NonNull StatementPolicy<A, D> alwaysCopyDeclared() {
128 return (StatementPolicy<A, D>) EqualSemantics.ALWAYS_COPY;
131 abstract boolean canReuseCurrent(@NonNull Current<A, D> copy, @NonNull Current<A, D> current,
132 @NonNull Collection<? extends EffectiveStatement<?, ?>> substatements);
134 private static final class AlwaysFail<A, D extends DeclaredStatement<A>> extends StatementPolicy<A, D> {
135 static final @NonNull AlwaysFail<?, ?> IGNORE = new AlwaysFail<>(CopyPolicy.IGNORE);
136 static final @NonNull AlwaysFail<?, ?> REJECT = new AlwaysFail<>(CopyPolicy.REJECT);
138 private AlwaysFail(final CopyPolicy copyPolicy) {
143 boolean canReuseCurrent(final Current<A, D> copy, final Current<A, D> current,
144 final Collection<? extends EffectiveStatement<?, ?>> substatements) {
145 throw new VerifyException("This implementation should never be invoked");
149 private static final class EqualSemantics<A, D extends DeclaredStatement<A>> extends StatementPolicy<A, D> {
150 static final @NonNull EqualSemantics<?, ?> ALWAYS_COPY =
151 new EqualSemantics<>((copy, stmt, substatements) -> false);
152 static final @NonNull EqualSemantics<?, ?> CONTEXT_INDEPENDENT =
153 new EqualSemantics<>(CopyPolicy.CONTEXT_INDEPENDENT, (copy, stmt, substatements) -> true);
154 static final @NonNull EqualSemantics<?, ?> EXACT_REPLICA =
155 new EqualSemantics<>(CopyPolicy.EXACT_REPLICA, (copy, stmt, substatements) -> true);
157 private final @NonNull StatementEquality<A, D> equality;
159 private EqualSemantics(final CopyPolicy copyPolicy, final StatementEquality<A, D> equality) {
161 this.equality = requireNonNull(equality);
164 EqualSemantics(final StatementEquality<A, D> equality) {
165 this(CopyPolicy.DECLARED_COPY, equality);
169 boolean canReuseCurrent(final Current<A, D> copy, final Current<A, D> current,
170 final Collection<? extends EffectiveStatement<?, ?>> substatements) {
171 return equality.canReuseCurrent(copy, current, substatements);
177 * Abstract base class for comparators associated with statements with a {@link CopyPolicy#DECLARED_COPY} copy
180 * @param <A> Argument type
181 * @param <D> Declared Statement representation
184 public interface StatementEquality<A, D extends DeclaredStatement<A>> {
186 * Determine whether {@code current} statement has the same semantics as the provided copy. See the contract
187 * specification of {@link StatementFactory#canReuseCurrent(Current, Current, Collection)}.
189 * @param copy Copy of current effective context
190 * @param current Current effective context
191 * @param substatements Current effective substatements
192 * @return True if {@code current} can be reused in place of {@code copy}, false if the copy needs to be used.
194 boolean canReuseCurrent(@NonNull Current<A, D> copy, @NonNull Current<A, D> current,
195 @NonNull Collection<? extends EffectiveStatement<?, ?>> substatements);
198 private final @NonNull StatementPolicy<A, D> policy;
199 private final @NonNull StatementDefinition def;
200 private final @NonNull CopyPolicy copyPolicy;
203 protected StatementSupport(final StatementSupport<A, D, E> delegate) {
204 checkArgument(delegate != this);
205 this.def = delegate.def;
206 this.policy = delegate.policy;
207 this.copyPolicy = delegate.copyPolicy;
211 protected StatementSupport(final StatementDefinition publicDefinition, final StatementPolicy<A, D> policy) {
212 checkArgument(publicDefinition != this);
213 this.def = requireNonNull(publicDefinition);
214 this.policy = requireNonNull(policy);
215 this.copyPolicy = policy.copyPolicy;
219 * Returns public statement definition, which will be present in built statements.
222 * Public statement definition may be used to provide different implementation of statement definition,
223 * which will not retain any build specific data or context.
225 * @return public statement definition, which will be present in built statements.
227 public final @NonNull StatementDefinition getPublicView() {
232 * Return this statement's {@link CopyPolicy}. This is a static value, reflecting how this statement reacts to being
233 * replicated to a different context, without reflecting on behaviour of potential substatements, which would come
234 * into play in something like:
248 * description "Can be used in description/reference statements to attach additional notes";
251 * description "A nice module extending description statement semantics" {
252 * foo:note "We can now attach description/reference a note.";
253 * foo:note "Also another note";
260 * In this scenario, it is the reactor's job to figure out what to do (like talking to substatements).
262 * @return This statement's copy policy
264 public final @NonNull CopyPolicy copyPolicy() {
269 public final boolean canReuseCurrent(final Current<A, D> copy, final Current<A, D> current,
270 final Collection<? extends EffectiveStatement<?, ?>> substatements) {
271 return policy.canReuseCurrent(copy, current, substatements);
275 * Parses textual representation of argument in object representation.
277 * @param ctx Context, which may be used to access source-specific namespaces required for parsing.
278 * @param value String representation of value, as was present in text source.
279 * @return Parsed value
280 * @throws SourceException when an inconsistency is detected.
282 public abstract A parseArgumentValue(StmtContext<?, ?, ?> ctx, String value);
285 * Adapts the argument value to match a new module. Default implementation returns original value stored in context,
286 * which is appropriate for most implementations.
288 * @param ctx Context, which may be used to access source-specific namespaces required for parsing.
289 * @param targetModule Target module, may not be null.
290 * @return Adapted argument value.
292 public A adaptArgumentValue(final @NonNull StmtContext<A, D, E> ctx, final @NonNull QNameModule targetModule) {
293 return ctx.argument();
297 * Invoked when a statement supported by this instance is added to build context. This allows implementations
298 * of this interface to start tracking the statement and perform any modifications to the build context hierarchy,
299 * accessible via {@link StmtContext#getParentContext()}. One such use is populating the parent's namespaces to
300 * allow it to locate this child statement.
302 * @param stmt Context of added statement. No substatements are available.
304 public void onStatementAdded(final @NonNull Mutable<A, D, E> stmt) {
305 // NOOP for most implementations
309 * Invoked when statement is closed during {@link ModelProcessingPhase#SOURCE_PRE_LINKAGE} phase, only substatements
310 * from this and previous phase are available.
313 * Implementation may use method to perform actions on this event or register modification action using
314 * {@link Mutable#newInferenceAction(ModelProcessingPhase)}.
316 * @param stmt Context of added statement.
318 public void onPreLinkageDeclared(final @NonNull Mutable<A, D, E> stmt) {
319 // NOOP for most implementations
323 * Invoked when statement is closed during {@link ModelProcessingPhase#SOURCE_LINKAGE} phase, only substatements
324 * from this and previous phase are available.
327 * Implementation may use method to perform actions on this event or register modification action using
328 * {@link StmtContext.Mutable#newInferenceAction(ModelProcessingPhase)}.
330 * @param stmt Context of added statement.
331 * @throws SourceException when an inconsistency is detected.
333 public void onLinkageDeclared(final @NonNull Mutable<A, D, E> stmt) {
334 // NOOP for most implementations
338 * Invoked when statement is closed during {@link ModelProcessingPhase#STATEMENT_DEFINITION} phase,
339 * only substatements from this phase are available.
342 * Implementation may use method to perform actions on this event or register modification action using
343 * {@link StmtContext.Mutable#newInferenceAction(ModelProcessingPhase)}.
345 * @param stmt Context of added statement. Argument and statement parent is accessible.
346 * @throws SourceException when an inconsistency is detected.
348 public void onStatementDefinitionDeclared(final Mutable<A, D, E> stmt) {
349 // NOOP for most implementations
353 * Invoked when statement is closed during {@link ModelProcessingPhase#FULL_DECLARATION} phase,
354 * only substatements from this phase are available.
357 * Implementation may use method to perform actions on this event or register modification action using
358 * {@link StmtContext.Mutable#newInferenceAction(ModelProcessingPhase)}.
360 * @param stmt Context of added statement. Argument and statement parent is accessible.
361 * @throws SourceException when an inconsistency is detected.
363 public void onFullDefinitionDeclared(final StmtContext.Mutable<A, D, E> stmt) {
364 final SubstatementValidator validator = getSubstatementValidator();
365 if (validator != null) {
366 validator.validate(stmt);
371 * Returns corresponding substatement validator of a statement support.
373 * @return substatement validator or null, if substatement validator is not defined
375 // FIXME: rename to 'substatementValidator' and perhaps let it be passed in?
376 protected abstract @Nullable SubstatementValidator getSubstatementValidator();
379 * Returns true if this support has argument specific supports.
381 * @return true if this support has argument specific supports.
383 public boolean hasArgumentSpecificSupports() {
384 // Most of statement supports don't have any argument specific supports, so return 'false'.
389 * If this support has argument specific supports, the method returns support specific for given argument
390 * (e.g. type statement support need to be specialized based on its argument), otherwise returns null.
392 * @param argument argument of statement
393 * @return statement support specific for supplied argument or null
395 public @Nullable StatementSupport<?, ?, ?> getSupportSpecificForArgument(final String argument) {
396 // Most of statement supports don't have any argument specific supports, so return null.
401 * Given a raw string representation of an argument, try to use a shared representation. Default implementation
404 * @param rawArgument Argument string
405 * @return A potentially-shard instance
407 public String internArgument(final String rawArgument) {
412 * Returns true if this statement support and all its substatements ignore if-feature statements (e.g. yang-data
413 * extension defined in <a href="https://tools.ietf.org/html/rfc8040#section-8">RFC 8040</a>). Default
414 * implementation returns false.
416 * @return true if this statement support ignores if-feature statements, otherwise false.
419 public boolean isIgnoringIfFeatures() {
424 * Returns true if this statement support and all its substatements ignore config statements (e.g. yang-data
425 * extension defined in <a href="https://tools.ietf.org/html/rfc8040#section-8">RFC 8040</a>). Default
426 * implementation returns false.
428 * @return true if this statement support ignores config statements,
432 public boolean isIgnoringConfig() {
437 public final QName getStatementName() {
438 return def.getStatementName();
442 public final Optional<ArgumentDefinition> getArgumentDefinition() {
443 return def.getArgumentDefinition();
447 // Non-final for compatible extensions
448 public Class<? extends DeclaredStatement<?>> getDeclaredRepresentationClass() {
449 return def.getDeclaredRepresentationClass();
453 // Non-final for compatible extensions
454 public Class<? extends EffectiveStatement<?,?>> getEffectiveRepresentationClass() {
455 return def.getEffectiveRepresentationClass();
459 * Statement context copy policy, indicating how should reactor handle statement copy operations. Every statement
460 * copied by the reactor is subject to this policy.
462 public enum CopyPolicy {
464 * Reuse the source statement context in the new place, as it cannot be affected by any further operations. This
465 * implies that the semantics of the effective statement are not affected by any of its substatements. Each
466 * of the substatements is free to make its own policy.
469 * This policy is typically used by static constant statements such as {@code description} or {@code length},
470 * where the baseline RFC7950 does not allow any impact. A {@code description} could hold an extension statement
471 * in which case this interaction would come into play. Normal YANG will see empty substatements, so the reactor
472 * will be free to complete reuse the context.
475 * In case any substatement is of stronger policy, it is up to the reactor to handle correct handling of
476 * resulting subobjects.
478 // TODO: does this mean source must have transitioned to ModelProcessingPhase.EFFECTIVE_MODEL?
481 * Reuse the source statement context in the new place completely. This policy is more stringent than
482 * {@link #CONTEXT_INDEPENDENT} in that the statement is dependent on circumstances of its original definition
483 * and any copy operation must replicate it exactly as is. This implies ignoring the usual policy of its
484 * substatements. A typical example of such a statement is {@code type}.
488 * Create a copy sharing declared instance, but otherwise having a separate disconnected lifecycle.
490 // TODO: will the copy transition to ModelProcessingPhase.FULL_DECLARATION or which phase?
493 * Reject any attempt to copy this statement. This is useful for statements that are defined as top-level
494 * constructs, such as {@code contact}, {@code deviation} and similar.
498 * Ignore this statement's existence for the purposes of the new place -- it is not impacted. This guidance
499 * is left here for completeness, as it can have justifiable uses (but I can't think of any). Any substatements
500 * need to be ignored, too.