package org.opendaylight.yangtools.yang.parser.stmt.reactor;
import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
import com.google.common.collect.HashMultimap;
-import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableList;
import com.google.common.collect.Multimap;
+import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
+import java.util.List;
import java.util.Map;
import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
import javax.annotation.Nullable;
import org.opendaylight.yangtools.concepts.Mutable;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.common.QNameModule;
-import org.opendaylight.yangtools.yang.common.YangConstants;
+import org.opendaylight.yangtools.yang.common.YangVersion;
+import org.opendaylight.yangtools.yang.model.api.ModuleIdentifier;
import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
import org.opendaylight.yangtools.yang.model.api.meta.IdentifierNamespace;
-import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
-import org.opendaylight.yangtools.yang.parser.spi.ExtensionNamespace;
-import org.opendaylight.yangtools.yang.parser.spi.meta.ImportedNamespaceContext;
+import org.opendaylight.yangtools.yang.model.api.meta.StatementSource;
+import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder;
import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase;
+import org.opendaylight.yangtools.yang.parser.spi.meta.MutableStatement;
import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour;
import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.NamespaceStorageNode;
import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.StorageNodeType;
+import org.opendaylight.yangtools.yang.parser.spi.meta.StatementDefinitionNamespace;
import org.opendaylight.yangtools.yang.parser.spi.meta.StatementSupport;
+import org.opendaylight.yangtools.yang.parser.spi.meta.StatementSupportBundle;
+import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
+import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
+import org.opendaylight.yangtools.yang.parser.spi.source.BelongsToModuleContext;
+import org.opendaylight.yangtools.yang.parser.spi.source.BelongsToPrefixToModuleCtx;
+import org.opendaylight.yangtools.yang.parser.spi.source.ImpPrefixToNamespace;
+import org.opendaylight.yangtools.yang.parser.spi.source.ImportPrefixToModuleCtx;
+import org.opendaylight.yangtools.yang.parser.spi.source.ImportedModuleContext;
+import org.opendaylight.yangtools.yang.parser.spi.source.ModuleCtxToModuleQName;
import org.opendaylight.yangtools.yang.parser.spi.source.PrefixToModule;
import org.opendaylight.yangtools.yang.parser.spi.source.PrefixToModuleMap;
import org.opendaylight.yangtools.yang.parser.spi.source.QNameToStatementDefinition;
import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
import org.opendaylight.yangtools.yang.parser.spi.source.StatementSourceReference;
import org.opendaylight.yangtools.yang.parser.spi.source.StatementStreamSource;
-import org.opendaylight.yangtools.yang.parser.stmt.reactor.StatementContextBase.ContextBuilder;
-import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.UnknownStatementImpl;
-import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.Utils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
public class SourceSpecificContext implements NamespaceStorageNode, NamespaceBehaviour.Registry, Mutable {
FINISHED
}
- private final StatementStreamSource source;
- private final BuildGlobalContext currentContext;
- private final Collection<NamespaceStorageNode> importedNamespaces = new ArrayList<>();
- private final Multimap<ModelProcessingPhase, ModifierImpl> modifiers = HashMultimap.create();
+ private static final Logger LOG = LoggerFactory.getLogger(SourceSpecificContext.class);
- private RootStatementContext<?,?, ?> root;
+ private final Multimap<ModelProcessingPhase, ModifierImpl> modifiers = HashMultimap.create();
+ private final QNameToStatementDefinitionMap qnameToStmtDefMap = new QNameToStatementDefinitionMap();
+ private final PrefixToModuleMap prefixToModuleMap = new PrefixToModuleMap();
+ private final BuildGlobalContext currentContext;
+ private final StatementStreamSource source;
+ /*
+ * "imported" namespaces in this source -- this points to RootStatementContexts of
+ * - modules imported via 'import' statement
+ * - parent module, declared via 'belongs-to' statement
+ */
+ private Collection<RootStatementContext<?, ?, ?>> importedNamespaces = ImmutableList.of();
+ private ModelProcessingPhase finishedPhase = ModelProcessingPhase.INIT;
private ModelProcessingPhase inProgressPhase;
- private ModelProcessingPhase finishedPhase;
- private final QNameToStatementDefinitionMap qNameToStmtDefMap = new QNameToStatementDefinitionMap();
- private final PrefixToModuleMap prefixToModuleMap = new PrefixToModuleMap();
+ private RootStatementContext<?, ?, ?> root;
+ SourceSpecificContext(final BuildGlobalContext currentContext, final StatementStreamSource source) {
+ this.currentContext = Preconditions.checkNotNull(currentContext);
+ this.source = Preconditions.checkNotNull(source);
+ }
- SourceSpecificContext(final BuildGlobalContext currentContext,final StatementStreamSource source) {
- this.source = source;
- this.currentContext = currentContext;
+ boolean isEnabledSemanticVersioning() {
+ return currentContext.isEnabledSemanticVersioning();
}
- StatementDefinitionContext<?,?,?> getDefinition(final QName name) {
- return currentContext.getStatementDefinition(name);
+ ModelProcessingPhase getInProgressPhase() {
+ return inProgressPhase;
}
- ContextBuilder<?, ?, ?> createDeclaredChild(final StatementContextBase<?, ?, ?> current, final QName name, final StatementSourceReference ref) {
- StatementDefinitionContext<?,?,?> def = getDefinition(name);
+ StatementContextBase<?, ?, ?> createDeclaredChild(final StatementContextBase<?, ?, ?> current, final int childId,
+ final QName name, final String argument, final StatementSourceReference ref) {
+ if (current != null) {
+ // Fast path: we are entering a statement which was emitted in previous phase
+ StatementContextBase<?, ?, ?> existing = current.lookupSubstatement(childId);
+ while (existing != null && StatementSource.CONTEXT == existing.getStatementSource()) {
+ existing = existing.lookupSubstatement(childId);
+ }
+ if (existing != null) {
+ return existing;
+ }
+ }
- //extensions
+ StatementDefinitionContext<?, ?, ?> def = currentContext.getStatementDefinition(getRootVersion(), name);
if (def == null) {
- if (Utils.isValidStatementDefinition(prefixToModuleMap, qNameToStmtDefMap, name)) {
- def = new StatementDefinitionContext<>(new UnknownStatementImpl.Definition(qNameToStmtDefMap.get(Utils.trimPrefix(name))));
+ def = currentContext.getModelDefinedStatementDefinition(name);
+ if (def == null) {
+ final StatementSupport<?, ?, ?> extension = qnameToStmtDefMap.get(name);
+ if (extension != null) {
+ def = new StatementDefinitionContext<>(extension);
+ currentContext.putModelDefinedStatementDefinition(name, def);
+ }
}
+ } else if (current != null && StmtContextUtils.isUnrecognizedStatement(current)) {
+ /*
+ * This code wraps statements encountered inside an extension so
+ * they do not get confused with regular statements.
+ */
+ def = Preconditions.checkNotNull(current.definition().getAsUnknownStatementDefinition(def),
+ "Unable to create unknown statement definition of yang statement %s in unknown statement %s", def,
+ current);
}
- Preconditions.checkArgument(def != null, "Statement %s does not have type mapping defined.", name);
- if(current == null) {
- return createDeclaredRoot(def,ref);
+ InferenceException.throwIfNull(def, ref, "Statement %s does not have type mapping defined.", name);
+ if (def.hasArgument()) {
+ SourceException.throwIfNull(argument, ref, "Statement %s requires an argument", name);
+ } else {
+ SourceException.throwIf(argument != null, ref, "Statement %s does not take argument", name);
}
- return current.substatementBuilder(def, ref);
- }
- @SuppressWarnings({ "rawtypes", "unchecked" })
- private ContextBuilder<?,?, ?> createDeclaredRoot(final StatementDefinitionContext<?,?,?> def, final StatementSourceReference ref) {
- return new ContextBuilder(def,ref) {
+ /*
+ * If the current statement definition has argument specific
+ * sub-definitions, get argument specific sub-definition based on given
+ * argument (e.g. type statement need to be specialized based on its
+ * argument).
+ */
+ if (def.hasArgumentSpecificSubDefinitions()) {
+ def = def.getSubDefinitionSpecificForArgument(argument);
+ }
- @Override
- public StatementContextBase build() throws SourceException {
- if(root == null) {
- root = new RootStatementContext(this, SourceSpecificContext.this);
- } else {
- Preconditions.checkState(root.getIdentifier().equals(getIdentifier()), "Root statement was already defined as %s.", root.getIdentifier());
- }
- root.resetLists();
- return root;
- }
+ if (current != null) {
+ return current.createSubstatement(childId, def, ref, argument);
+ }
- };
+ /*
+ * If root is null or root version is other than default,
+ * we need to create new root.
+ */
+ if (root == null) {
+ root = new RootStatementContext<>(this, def, ref, argument);
+ } else if (!RootStatementContext.DEFAULT_VERSION.equals(root.getRootVersion())
+ && inProgressPhase == ModelProcessingPhase.SOURCE_LINKAGE) {
+ root = new RootStatementContext<>(this, def, ref, argument, root.getRootVersion(),
+ root.getRootIdentifier());
+ } else {
+ final QName rootStatement = root.definition().getStatementName();
+ final String rootArgument = root.rawStatementArgument();
+
+ Preconditions.checkState(Objects.equals(def.getStatementName(), rootStatement)
+ && Objects.equals(argument, rootArgument), "Root statement was already defined as '%s %s'.",
+ rootStatement, rootArgument);
+ }
+ return root;
}
- RootStatementContext<?,?,?> getRoot() {
+ RootStatementContext<?, ?, ?> getRoot() {
return root;
}
+ /**
+ * Return version of root statement context.
+ *
+ * @return version of root statement context
+ */
+ YangVersion getRootVersion() {
+ return root != null ? root.getRootVersion() : RootStatementContext.DEFAULT_VERSION;
+ }
+
DeclaredStatement<?> buildDeclared() {
return root.buildDeclared();
}
- EffectiveStatement<?,?> buildEffective() {
+ EffectiveStatement<?, ?> buildEffective() {
return root.buildEffective();
}
void startPhase(final ModelProcessingPhase phase) {
- @Nullable ModelProcessingPhase previousPhase = phase.getPreviousPhase();
- Preconditions.checkState(Objects.equals(previousPhase, finishedPhase));
- Preconditions.checkState(modifiers.get(previousPhase).isEmpty());
+ @Nullable final ModelProcessingPhase previousPhase = phase.getPreviousPhase();
+ Verify.verify(Objects.equals(previousPhase, finishedPhase),
+ "Phase sequencing violation: previous phase should be %s, source %s has %s", previousPhase, source,
+ finishedPhase);
+
+ final Collection<ModifierImpl> previousModifiers = modifiers.get(previousPhase);
+ Preconditions.checkState(previousModifiers.isEmpty(),
+ "Previous phase %s has unresolved modifiers %s in source %s", previousPhase, previousModifiers, source);
+
inProgressPhase = phase;
+ LOG.debug("Source {} started phase {}", source, phase);
+ }
+
+ private void updateImportedNamespaces(final Class<?> type, final Object value) {
+ if (BelongsToModuleContext.class.isAssignableFrom(type) || ImportedModuleContext.class.isAssignableFrom(type)) {
+ if (importedNamespaces.isEmpty()) {
+ importedNamespaces = new ArrayList<>(1);
+ }
+
+ Verify.verify(value instanceof RootStatementContext);
+ importedNamespaces.add((RootStatementContext<?, ?, ?>) value);
+ }
}
@Override
- public <K, V, N extends IdentifierNamespace<K, V>> void addToLocalStorage(final Class<N> type, final K key, final V value) {
- if(ImportedNamespaceContext.class.isAssignableFrom(type)) {
- importedNamespaces.add((NamespaceStorageNode) value);
+ public <K, V, N extends IdentifierNamespace<K, V>> V putToLocalStorage(final Class<N> type, final K key,
+ final V value) {
+ // RootStatementContext takes care of IncludedModuleContext and the rest...
+ final V ret = getRoot().putToLocalStorage(type, key, value);
+ // FIXME: what about duplicates?
+ updateImportedNamespaces(type, value);
+ return ret;
+ }
+
+ @Override
+ public <K, V, N extends IdentifierNamespace<K, V>> V putToLocalStorageIfAbsent(final Class<N> type, final K key,
+ final V value) {
+ // RootStatementContext takes care of IncludedModuleContext and the rest...
+ final V ret = getRoot().putToLocalStorageIfAbsent(type, key, value);
+ if (ret == null) {
+ updateImportedNamespaces(type, value);
}
- getRoot().addToLocalStorage(type, key, value);
+ return ret;
}
@Override
@Override
public <K, V, N extends IdentifierNamespace<K, V>> V getFromLocalStorage(final Class<N> type, final K key) {
final V potentialLocal = getRoot().getFromLocalStorage(type, key);
- if(potentialLocal != null) {
+ if (potentialLocal != null) {
+ return potentialLocal;
+ }
+
+ for (final NamespaceStorageNode importedSource : importedNamespaces) {
+ final V potential = importedSource.getFromLocalStorage(type, key);
+ if (potential != null) {
+ return potential;
+ }
+ }
+ return null;
+ }
+
+ @Nullable
+ @Override
+ public <K, V, N extends IdentifierNamespace<K, V>> Map<K, V> getAllFromLocalStorage(final Class<N> type) {
+ final Map<K, V> potentialLocal = getRoot().getAllFromLocalStorage(type);
+ if (potentialLocal != null) {
return potentialLocal;
}
- for(NamespaceStorageNode importedSource : importedNamespaces) {
- V potential = importedSource.getFromLocalStorage(type, key);
- if(potential != null) {
+
+ for (final NamespaceStorageNode importedSource : importedNamespaces) {
+ final Map<K, V> potential = importedSource.getAllFromLocalStorage(type);
+
+ if (potential != null) {
return potential;
}
}
}
@Override
- public <K, V, N extends IdentifierNamespace<K, V>> NamespaceBehaviour<K, V, N> getNamespaceBehaviour(final Class<N> type) {
+ public <K, V, N extends IdentifierNamespace<K, V>> NamespaceBehaviour<K, V, N> getNamespaceBehaviour(
+ final Class<N> type) {
return currentContext.getNamespaceBehaviour(type);
}
}
PhaseCompletionProgress tryToCompletePhase(final ModelProcessingPhase phase) throws SourceException {
- Collection<ModifierImpl> currentPhaseModifiers = modifiers.get(phase);
+ final Collection<ModifierImpl> currentPhaseModifiers = modifiers.get(phase);
- boolean hasProgressed = hasProgress(currentPhaseModifiers);
+ boolean hasProgressed = tryToProgress(currentPhaseModifiers);
- boolean phaseCompleted = root.tryToCompletePhase(phase);
+ Preconditions.checkNotNull(this.root, "Malformed source. Valid root element is missing.");
+ final boolean phaseCompleted = root.tryToCompletePhase(phase);
- hasProgressed = (hasProgress(currentPhaseModifiers) | hasProgressed);
+ hasProgressed |= tryToProgress(currentPhaseModifiers);
- if(phaseCompleted && (currentPhaseModifiers.isEmpty())) {
+ if (phaseCompleted && currentPhaseModifiers.isEmpty()) {
finishedPhase = phase;
+ LOG.debug("Source {} finished phase {}", source, phase);
return PhaseCompletionProgress.FINISHED;
}
- if(hasProgressed) {
- return PhaseCompletionProgress.PROGRESS;
- }
- return PhaseCompletionProgress.NO_PROGRESS;
- }
-
- private static boolean hasProgress(final Collection<ModifierImpl> currentPhaseModifiers) {
+ return hasProgressed ? PhaseCompletionProgress.PROGRESS : PhaseCompletionProgress.NO_PROGRESS;
+ }
- Iterator<ModifierImpl> modifier = currentPhaseModifiers.iterator();
+ private static boolean tryToProgress(final Collection<ModifierImpl> currentPhaseModifiers) {
boolean hasProgressed = false;
- while(modifier.hasNext()) {
- if(modifier.next().isApplied()) {
+
+ // Try making forward progress ...
+ final Iterator<ModifierImpl> modifier = currentPhaseModifiers.iterator();
+ while (modifier.hasNext()) {
+ if (modifier.next().tryApply()) {
modifier.remove();
hasProgressed = true;
}
}
return hasProgressed;
-
}
ModelActionBuilder newInferenceAction(final ModelProcessingPhase phase) {
- ModifierImpl action = new ModifierImpl(phase);
+ final ModifierImpl action = new ModifierImpl();
modifiers.put(phase, action);
return action;
}
+ finishedPhase + "]";
}
- SourceException failModifiers(final ModelProcessingPhase identifier) {
- InferenceException sourceEx = new InferenceException("Fail to infer source relationships", root.getStatementSourceReference());
-
-
- for(ModifierImpl mod : modifiers.get(identifier)) {
+ Optional<SourceException> failModifiers(final ModelProcessingPhase identifier) {
+ final List<SourceException> exceptions = new ArrayList<>();
+ for (final ModifierImpl mod : modifiers.get(identifier)) {
try {
mod.failModifier();
- } catch (SourceException e) {
- sourceEx.addSuppressed(e);
+ } catch (final SourceException e) {
+ exceptions.add(e);
}
}
- return sourceEx;
+
+ if (exceptions.isEmpty()) {
+ return Optional.empty();
+ }
+
+ final String message = String.format("Yang model processing phase %s failed", identifier);
+ final InferenceException e = new InferenceException(message, root.getStatementSourceReference(),
+ exceptions.get(0));
+ exceptions.listIterator(1).forEachRemaining(e::addSuppressed);
+
+ return Optional.of(e);
}
void loadStatements() throws SourceException {
+ LOG.trace("Source {} loading statements for phase {}", source, inProgressPhase);
+
switch (inProgressPhase) {
+ case SOURCE_PRE_LINKAGE:
+ source.writePreLinkage(new StatementContextWriter(this, inProgressPhase), stmtDef());
+ break;
case SOURCE_LINKAGE:
- source.writeLinkage(new StatementContextWriter(this, inProgressPhase),stmtDef());
- break;
+ source.writeLinkage(new StatementContextWriter(this, inProgressPhase), stmtDef(), preLinkagePrefixes(),
+ getRootVersion());
+ break;
case STATEMENT_DEFINITION:
- source.writeLinkageAndStatementDefinitions(new StatementContextWriter(this, inProgressPhase), stmtDef(), prefixes());
- break;
+ source.writeLinkageAndStatementDefinitions(new StatementContextWriter(this, inProgressPhase), stmtDef(),
+ prefixes(), getRootVersion());
+ break;
case FULL_DECLARATION:
- source.writeFull(new StatementContextWriter(this, inProgressPhase), stmtDef(), prefixes());
- break;
- default:
- break;
+ source.writeFull(new StatementContextWriter(this, inProgressPhase), stmtDef(), prefixes(),
+ getRootVersion());
+ break;
+ default:
+ break;
}
}
+ private PrefixToModule preLinkagePrefixes() {
+ final PrefixToModuleMap preLinkagePrefixes = new PrefixToModuleMap(true);
+ final Map<String, URI> prefixToNamespaceMap = getAllFromLocalStorage(ImpPrefixToNamespace.class);
+ if (prefixToNamespaceMap == null) {
+ //:FIXME if it is a submodule without any import, the map is null. Handle also submodules and includes...
+ return null;
+ }
+
+ prefixToNamespaceMap.forEach((key, value) -> preLinkagePrefixes.put(key, QNameModule.create(value, null)));
+ return preLinkagePrefixes;
+ }
+
private PrefixToModule prefixes() {
- Map<String, QNameModule> prefixes = (Map<String, QNameModule>) currentContext.getAllFromNamespace(PrefixToModule.class);
- for (Map.Entry<String, QNameModule> prefix : prefixes.entrySet()) {
- prefixToModuleMap.put(prefix.getKey(), prefix.getValue());
+ final Map<String, StmtContext<?, ?, ?>> allImports = getRoot().getAllFromNamespace(
+ ImportPrefixToModuleCtx.class);
+ if (allImports != null) {
+ allImports.forEach((key, value) ->
+ prefixToModuleMap.put(key, getRoot().getFromNamespace(ModuleCtxToModuleQName.class, value)));
}
+
+ final Map<String, StmtContext<?, ?, ?>> allBelongsTo = getRoot().getAllFromNamespace(
+ BelongsToPrefixToModuleCtx.class);
+ if (allBelongsTo != null) {
+ allBelongsTo.forEach((key, value) ->
+ prefixToModuleMap.put(key, getRoot().getFromNamespace(ModuleCtxToModuleQName.class, value)));
+ }
+
return prefixToModuleMap;
}
private QNameToStatementDefinition stmtDef() {
- //regular YANG statements added
- ImmutableMap<QName, StatementSupport<?, ?, ?>> definitions = currentContext.getSupportsForPhase(
- inProgressPhase).getDefinitions();
- for (Map.Entry<QName, StatementSupport<?,?,?>> entry : definitions.entrySet()) {
- qNameToStmtDefMap.put(entry.getKey(), entry.getValue());
+ // regular YANG statements and extension supports added
+ final StatementSupportBundle supportsForPhase = currentContext.getSupportsForPhase(inProgressPhase);
+ qnameToStmtDefMap.putAll(supportsForPhase.getCommonDefinitions());
+ qnameToStmtDefMap.putAll(supportsForPhase.getDefinitionsSpecificForVersion(getRootVersion()));
+
+ // No further actions needed
+ if (inProgressPhase != ModelProcessingPhase.FULL_DECLARATION) {
+ return qnameToStmtDefMap;
}
- //extensions added
- if (inProgressPhase.equals(ModelProcessingPhase.FULL_DECLARATION)) {
- Map<QName, SubstatementContext<?, ?, ?>> extensions = (Map<QName, SubstatementContext<?, ?, ?>>) currentContext.getAllFromNamespace(ExtensionNamespace.class);
- if (extensions != null) {
- for (Map.Entry<QName, SubstatementContext<?, ?, ?>> extension : extensions.entrySet()) {
- qNameToStmtDefMap.put(new QName(YangConstants.RFC6020_YIN_NAMESPACE, extension.getKey().getLocalName()), (StatementDefinition) extension.getValue().definition().getFactory());
+ // We need to any and all extension statements which have been declared in the context
+ final Map<QName, StatementSupport<?, ?, ?>> extensions = currentContext.getAllFromNamespace(
+ StatementDefinitionNamespace.class);
+ if (extensions != null) {
+ extensions.forEach((qname, support) -> {
+ final StatementSupport<?, ?, ?> existing = qnameToStmtDefMap.putIfAbsent(qname, support);
+ if (existing != null) {
+ LOG.debug("Source {} already defines statement {} as {}", source, qname, existing);
+ } else {
+ LOG.debug("Source {} defined statement {} as {}", source, qname, support);
}
- }
+ });
}
- return qNameToStmtDefMap;
+
+ return qnameToStmtDefMap;
+ }
+
+ public Set<YangVersion> getSupportedVersions() {
+ return currentContext.getSupportedVersions();
+ }
+
+ void addMutableStmtToSeal(final MutableStatement mutableStatement) {
+ currentContext.addMutableStmtToSeal(mutableStatement);
+ }
+
+ Collection<SourceIdentifier> getRequiredSources() {
+ return root.getRequiredSources();
+ }
+
+ ModuleIdentifier getRootIdentifier() {
+ return root.getRootIdentifier();
}
}