BUG 827: Add support for multiple choice case statements within one augument in confi...
[controller.git] / opendaylight / config / yang-jmx-generator / src / main / java / org / opendaylight / controller / config / yangjmxgenerator / ModuleMXBeanEntryBuilder.java
diff --git a/opendaylight/config/yang-jmx-generator/src/main/java/org/opendaylight/controller/config/yangjmxgenerator/ModuleMXBeanEntryBuilder.java b/opendaylight/config/yang-jmx-generator/src/main/java/org/opendaylight/controller/config/yangjmxgenerator/ModuleMXBeanEntryBuilder.java
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+/*
+ * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.config.yangjmxgenerator;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.AbstractDependencyAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.AttributeIfc;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.DependencyAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.JavaAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.ListAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.ListDependenciesAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.attribute.TOAttribute;
+import org.opendaylight.controller.config.yangjmxgenerator.plugin.util.NameConflictException;
+import org.opendaylight.yangtools.yang.common.QName;
+import org.opendaylight.yangtools.yang.model.api.AugmentationSchema;
+import org.opendaylight.yangtools.yang.model.api.ChoiceCaseNode;
+import org.opendaylight.yangtools.yang.model.api.ContainerSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.DataNodeContainer;
+import org.opendaylight.yangtools.yang.model.api.DataSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.IdentitySchemaNode;
+import org.opendaylight.yangtools.yang.model.api.LeafListSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.LeafSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.ListSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.Module;
+import org.opendaylight.yangtools.yang.model.api.ModuleImport;
+import org.opendaylight.yangtools.yang.model.api.RevisionAwareXPath;
+import org.opendaylight.yangtools.yang.model.api.SchemaContext;
+import org.opendaylight.yangtools.yang.model.api.SchemaPath;
+import org.opendaylight.yangtools.yang.model.api.UnknownSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.UsesNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nullable;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static com.google.common.base.Preconditions.checkState;
+import static java.lang.String.format;
+import static org.opendaylight.controller.config.yangjmxgenerator.ConfigConstants.createConfigQName;
+
+final class ModuleMXBeanEntryBuilder {
+
+    private Module currentModule;
+    private Map<QName, ServiceInterfaceEntry> qNamesToSIEs;
+    private SchemaContext schemaContext;
+    private TypeProviderWrapper typeProviderWrapper;
+    private String packageName;
+
+    public ModuleMXBeanEntryBuilder setModule(Module module) {
+        this.currentModule = module;
+        return this;
+    }
+
+    public ModuleMXBeanEntryBuilder setqNamesToSIEs(Map<QName, ServiceInterfaceEntry> qNamesToSIEs) {
+        this.qNamesToSIEs = qNamesToSIEs;
+        return this;
+    }
+
+    public ModuleMXBeanEntryBuilder setSchemaContext(SchemaContext schemaContext) {
+        this.schemaContext = schemaContext;
+        return this;
+    }
+
+    public ModuleMXBeanEntryBuilder setTypeProviderWrapper(TypeProviderWrapper typeProviderWrapper) {
+        this.typeProviderWrapper = typeProviderWrapper;
+        return this;
+    }
+
+    public ModuleMXBeanEntryBuilder setPackageName(String packageName) {
+        this.packageName = packageName;
+        return this;
+    }
+
+    private static final Logger logger = LoggerFactory
+            .getLogger(ModuleMXBeanEntryBuilder.class);
+
+    // TODO: the XPath should be parsed by code generator IMO
+    private static final String MAGIC_STRING = "MAGIC_STRING";
+    private static final String MODULE_CONDITION_XPATH_TEMPLATE = "^/MAGIC_STRING:modules/MAGIC_STRING:module/MAGIC_STRING:type\\s*=\\s*['\"](.+)['\"]$";
+    private static final SchemaPath expectedConfigurationAugmentationSchemaPath = new SchemaPath(
+            Arrays.asList(createConfigQName("modules"),
+                    createConfigQName("module"),
+                    createConfigQName("configuration")), true);
+    private static final SchemaPath expectedStateAugmentationSchemaPath = new SchemaPath(
+            Arrays.asList(createConfigQName("modules"),
+                    createConfigQName("module"), createConfigQName("state")),
+            true);
+    private static final Pattern PREFIX_COLON_LOCAL_NAME = Pattern
+            .compile("^(.+):(.+)$");
+
+
+    public Map<String, ModuleMXBeanEntry> build() {
+        logger.debug("Generating ModuleMXBeans of {} to package {}",
+                currentModule.getNamespace(), packageName);
+
+        String configModulePrefix;
+        try {
+            configModulePrefix = getConfigModulePrefixFromImport(currentModule);
+        } catch (IllegalArgumentException e) {
+            // this currentModule does not import config currentModule
+            return Collections.emptyMap();
+        }
+
+        // get identities of base config:currentModule-type
+        Map<String, IdentitySchemaNode> moduleIdentities =  getIdentityMap();
+
+        Map<String, QName> uniqueGeneratedClassesNames = new HashMap<>();
+
+        // each currentModule name should have an augmentation defined
+        Map<String, IdentitySchemaNode> unaugmentedModuleIdentities = new HashMap<>(
+                moduleIdentities);
+
+        Map<String, ModuleMXBeanEntry> result = new HashMap<>();
+
+        for (AugmentationSchema augmentation : currentModule.getAugmentations()) {
+            Set<DataSchemaNode> childNodes = augmentation.getChildNodes();
+            if (areAllChildrenChoiceCaseNodes(childNodes)) {
+                for (ChoiceCaseNode childCase : castChildNodesToChoiceCases(childNodes)) {
+                    // TODO refactor, extract to standalone builder class
+                    processChoiceCaseNode(result, uniqueGeneratedClassesNames, configModulePrefix, moduleIdentities,
+                            unaugmentedModuleIdentities, augmentation, childCase);
+                }
+            } // skip if child nodes are not all cases
+        }
+        // clean up nulls
+        cleanUpNulls(result);
+        // check attributes name uniqueness
+        checkAttributeNamesUniqueness(uniqueGeneratedClassesNames, result);
+        checkUnaugumentedIdentities(unaugmentedModuleIdentities);
+
+        logger.debug("Number of ModuleMXBeans to be generated: {}", result.size());
+
+        return result;
+    }
+
+    private static void cleanUpNulls(Map<String, ModuleMXBeanEntry> result) {
+        for (Map.Entry<String, ModuleMXBeanEntry> entry : result.entrySet()) {
+            ModuleMXBeanEntry module = entry.getValue();
+            if (module.getAttributes() == null) {
+                module.setYangToAttributes(Collections
+                        .<String, AttributeIfc> emptyMap());
+            } else if (module.getRuntimeBeans() == null) {
+                module.setRuntimeBeans(Collections
+                        .<RuntimeBeanEntry> emptyList());
+            }
+        }
+    }
+
+    private static void checkUnaugumentedIdentities(Map<String, IdentitySchemaNode> unaugmentedModuleIdentities) {
+        if (unaugmentedModuleIdentities.size() > 0) {
+            logger.warn("Augmentation not found for all currentModule identities: {}",
+                    unaugmentedModuleIdentities.keySet());
+        }
+    }
+
+    private static void checkAttributeNamesUniqueness(Map<String, QName> uniqueGeneratedClassesNames, Map<String, ModuleMXBeanEntry> result) {
+        for (Map.Entry<String, ModuleMXBeanEntry> entry : result.entrySet()) {
+            checkUniqueRuntimeBeanAttributesName(entry.getValue(),
+                    uniqueGeneratedClassesNames);
+        }
+    }
+
+    private Map<String, IdentitySchemaNode> getIdentityMap() {
+        Map<String, IdentitySchemaNode> moduleIdentities = Maps.newHashMap();
+
+        for (IdentitySchemaNode id : currentModule.getIdentities()) {
+            if (id.getBaseIdentity() != null
+                    && ConfigConstants.MODULE_TYPE_Q_NAME.equals(id.getBaseIdentity().getQName())) {
+                String identityLocalName = id.getQName().getLocalName();
+                if (moduleIdentities.containsKey(identityLocalName)) {
+                    throw new IllegalStateException("Module name already defined in this currentModule: "
+                            + identityLocalName);
+                } else {
+                    moduleIdentities.put(identityLocalName, id);
+                    logger.debug("Found identity {}", identityLocalName);
+                }
+                // validation check on unknown schema nodes
+                boolean providedServiceWasSet = false;
+                for (UnknownSchemaNode unknownNode : id.getUnknownSchemaNodes()) {
+                    // TODO: test this
+                    if (ConfigConstants.PROVIDED_SERVICE_EXTENSION_QNAME.equals(unknownNode.getNodeType())) {
+                        // no op: 0 or more provided identities are allowed
+                    } else if (ConfigConstants.JAVA_NAME_PREFIX_EXTENSION_QNAME.equals(unknownNode.getNodeType())) {
+                        // 0..1 allowed
+                        checkState(
+                                providedServiceWasSet == false,
+                                format("More than one language extension %s is not allowed here: %s",
+                                        ConfigConstants.JAVA_NAME_PREFIX_EXTENSION_QNAME, id));
+                        providedServiceWasSet = true;
+                    } else {
+                        throw new IllegalStateException("Unexpected language extension " + unknownNode.getNodeType());
+                    }
+                }
+            }
+        }
+
+        return moduleIdentities;
+    }
+
+    private Collection<ChoiceCaseNode> castChildNodesToChoiceCases(Set<DataSchemaNode> childNodes) {
+        return Collections2.transform(childNodes, new Function<DataSchemaNode, ChoiceCaseNode>() {
+            @Nullable
+            @Override
+            public ChoiceCaseNode apply(@Nullable DataSchemaNode input) {
+                return (ChoiceCaseNode) input;
+            }
+        });
+    }
+
+    private boolean areAllChildrenChoiceCaseNodes(Set<DataSchemaNode> childNodes) {
+        for (DataSchemaNode childNode : childNodes) {
+            if (childNode instanceof ChoiceCaseNode == false)
+                return false;
+        }
+        return true;
+    }
+
+    private void processChoiceCaseNode(Map<String, ModuleMXBeanEntry> result,
+            Map<String, QName> uniqueGeneratedClassesNames, String configModulePrefix,
+            Map<String, IdentitySchemaNode> moduleIdentities,
+            Map<String, IdentitySchemaNode> unaugmentedModuleIdentities, AugmentationSchema augmentation,
+            DataSchemaNode when) {
+
+        ChoiceCaseNode choiceCaseNode = (ChoiceCaseNode) when;
+        if (choiceCaseNode.getConstraints() == null || choiceCaseNode.getConstraints().getWhenCondition() == null) {
+            return;
+        }
+        RevisionAwareXPath xPath = choiceCaseNode.getConstraints().getWhenCondition();
+        Matcher matcher = getWhenConditionMatcher(configModulePrefix, xPath);
+        if (matcher.matches() == false) {
+            return;
+        }
+        String moduleLocalNameFromXPath = matcher.group(1);
+        IdentitySchemaNode moduleIdentity = moduleIdentities.get(moduleLocalNameFromXPath);
+        unaugmentedModuleIdentities.remove(moduleLocalNameFromXPath);
+        checkState(moduleIdentity != null, "Cannot find identity " + moduleLocalNameFromXPath
+                + " matching augmentation " + augmentation);
+        Map<String, QName> providedServices = findProvidedServices(moduleIdentity, currentModule, qNamesToSIEs,
+                schemaContext);
+
+        if (moduleIdentity == null) {
+            throw new IllegalStateException("Cannot find identity specified by augmentation xpath constraint: "
+                    + moduleLocalNameFromXPath + " of " + augmentation);
+        }
+        String javaNamePrefix = TypeProviderWrapper.findJavaNamePrefix(moduleIdentity);
+
+        Map<String, AttributeIfc> yangToAttributes = null;
+        // runtime-data
+        Collection<RuntimeBeanEntry> runtimeBeans = null;
+
+        if (expectedConfigurationAugmentationSchemaPath.equals(augmentation.getTargetPath())) {
+            logger.debug("Parsing configuration of {}", moduleLocalNameFromXPath);
+            yangToAttributes = fillConfiguration(choiceCaseNode, currentModule, typeProviderWrapper, qNamesToSIEs,
+                    schemaContext, packageName);
+            checkUniqueAttributesWithGeneratedClass(uniqueGeneratedClassesNames, when.getQName(), yangToAttributes);
+        } else if (expectedStateAugmentationSchemaPath.equals(augmentation.getTargetPath())) {
+            logger.debug("Parsing state of {}", moduleLocalNameFromXPath);
+            try {
+                runtimeBeans = fillRuntimeBeans(choiceCaseNode, currentModule, typeProviderWrapper, packageName,
+                        moduleLocalNameFromXPath, javaNamePrefix);
+            } catch (NameConflictException e) {
+                throw new NameConflictException(e.getConflictingName(), when.getQName(), when.getQName());
+            }
+            checkUniqueRuntimeBeansGeneratedClasses(uniqueGeneratedClassesNames, when, runtimeBeans);
+            Set<RuntimeBeanEntry> runtimeBeanEntryValues = Sets.newHashSet(runtimeBeans);
+            for (RuntimeBeanEntry entry : runtimeBeanEntryValues) {
+                checkUniqueAttributesWithGeneratedClass(uniqueGeneratedClassesNames, when.getQName(),
+                        entry.getYangPropertiesToTypesMap());
+            }
+
+        } else {
+            throw new IllegalArgumentException("Cannot parse augmentation " + augmentation);
+        }
+        if (result.containsKey(moduleLocalNameFromXPath)) {
+            // either fill runtimeBeans or yangToAttributes
+            ModuleMXBeanEntry moduleMXBeanEntry = result.get(moduleLocalNameFromXPath);
+            if (yangToAttributes != null && moduleMXBeanEntry.getAttributes() == null) {
+                moduleMXBeanEntry.setYangToAttributes(yangToAttributes);
+            } else if (runtimeBeans != null && moduleMXBeanEntry.getRuntimeBeans() == null) {
+                moduleMXBeanEntry.setRuntimeBeans(runtimeBeans);
+            }
+        } else {
+            ModuleMXBeanEntry.ModuleMXBeanEntryInitial initial = new ModuleMXBeanEntry.ModuleMXBeanEntryInitialBuilder()
+                    .setIdSchemaNode(moduleIdentity).setPackageName(packageName).setJavaNamePrefix(javaNamePrefix)
+                    .setNamespace(currentModule.getNamespace().toString()).setqName(ModuleUtil.getQName(currentModule))
+                    .build();
+
+            // construct ModuleMXBeanEntry
+            ModuleMXBeanEntry moduleMXBeanEntry = new ModuleMXBeanEntry(initial, yangToAttributes, providedServices,
+                    runtimeBeans);
+
+            moduleMXBeanEntry.setYangModuleName(currentModule.getName());
+            moduleMXBeanEntry.setYangModuleLocalname(moduleLocalNameFromXPath);
+            result.put(moduleLocalNameFromXPath, moduleMXBeanEntry);
+        }
+    }
+
+    private void checkUniqueRuntimeBeansGeneratedClasses(Map<String, QName> uniqueGeneratedClassesNames,
+            DataSchemaNode when, Collection<RuntimeBeanEntry> runtimeBeans) {
+        for (RuntimeBeanEntry runtimeBean : runtimeBeans) {
+            final String javaNameOfRuntimeMXBean = runtimeBean.getJavaNameOfRuntimeMXBean();
+            if (uniqueGeneratedClassesNames.containsKey(javaNameOfRuntimeMXBean)) {
+                QName firstDefinedQName = uniqueGeneratedClassesNames.get(javaNameOfRuntimeMXBean);
+                throw new NameConflictException(javaNameOfRuntimeMXBean, firstDefinedQName, when.getQName());
+            }
+            uniqueGeneratedClassesNames.put(javaNameOfRuntimeMXBean, when.getQName());
+        }
+    }
+
+    private static void checkUniqueRuntimeBeanAttributesName(ModuleMXBeanEntry mxBeanEntry,
+            Map<String, QName> uniqueGeneratedClassesNames) {
+        for (RuntimeBeanEntry runtimeBeanEntry : mxBeanEntry.getRuntimeBeans()) {
+            for (String runtimeAttName : runtimeBeanEntry.getYangPropertiesToTypesMap().keySet()) {
+                if (mxBeanEntry.getAttributes().keySet().contains(runtimeAttName)) {
+                    QName qName1 = uniqueGeneratedClassesNames.get(runtimeBeanEntry.getJavaNameOfRuntimeMXBean());
+                    QName qName2 = uniqueGeneratedClassesNames.get(mxBeanEntry.getGloballyUniqueName());
+                    throw new NameConflictException(runtimeAttName, qName1, qName2);
+                }
+            }
+        }
+    }
+
+    private void checkUniqueAttributesWithGeneratedClass(Map<String, QName> uniqueGeneratedClassNames,
+            QName parentQName, Map<String, AttributeIfc> yangToAttributes) {
+        for (Map.Entry<String, AttributeIfc> attr : yangToAttributes.entrySet()) {
+            if (attr.getValue() instanceof TOAttribute) {
+                checkUniqueTOAttr(uniqueGeneratedClassNames, parentQName, (TOAttribute) attr.getValue());
+            } else if (attr.getValue() instanceof ListAttribute
+                    && ((ListAttribute) attr.getValue()).getInnerAttribute() instanceof TOAttribute) {
+                checkUniqueTOAttr(uniqueGeneratedClassNames, parentQName,
+                        (TOAttribute) ((ListAttribute) attr.getValue()).getInnerAttribute());
+            }
+        }
+    }
+
+    private void checkUniqueTOAttr(Map<String, QName> uniqueGeneratedClassNames, QName parentQName, TOAttribute attr) {
+        final String upperCaseCammelCase = attr.getUpperCaseCammelCase();
+        if (uniqueGeneratedClassNames.containsKey(upperCaseCammelCase)) {
+            QName firstDefinedQName = uniqueGeneratedClassNames.get(upperCaseCammelCase);
+            throw new NameConflictException(upperCaseCammelCase, firstDefinedQName, parentQName);
+        } else {
+            uniqueGeneratedClassNames.put(upperCaseCammelCase, parentQName);
+        }
+    }
+
+    private Collection<RuntimeBeanEntry> fillRuntimeBeans(ChoiceCaseNode choiceCaseNode, Module currentModule,
+            TypeProviderWrapper typeProviderWrapper, String packageName, String moduleLocalNameFromXPath,
+            String javaNamePrefix) {
+
+        return RuntimeBeanEntry.extractClassNameToRuntimeBeanMap(packageName, choiceCaseNode, moduleLocalNameFromXPath,
+                typeProviderWrapper, javaNamePrefix, currentModule).values();
+
+    }
+
+    private Map<String, AttributeIfc> fillConfiguration(ChoiceCaseNode choiceCaseNode, Module currentModule,
+            TypeProviderWrapper typeProviderWrapper, Map<QName, ServiceInterfaceEntry> qNamesToSIEs,
+            SchemaContext schemaContext, String packageName) {
+        Map<String, AttributeIfc> yangToAttributes = new HashMap<>();
+        for (DataSchemaNode attrNode : choiceCaseNode.getChildNodes()) {
+            AttributeIfc attributeValue = getAttributeValue(attrNode, currentModule, qNamesToSIEs, typeProviderWrapper,
+                    schemaContext, packageName);
+            yangToAttributes.put(attributeValue.getAttributeYangName(), attributeValue);
+        }
+        return yangToAttributes;
+    }
+
+    private Map<String, QName> findProvidedServices(IdentitySchemaNode moduleIdentity, Module currentModule,
+            Map<QName, ServiceInterfaceEntry> qNamesToSIEs, SchemaContext schemaContext) {
+        Map<String, QName> result = new HashMap<>();
+        for (UnknownSchemaNode unknownNode : moduleIdentity.getUnknownSchemaNodes()) {
+            if (ConfigConstants.PROVIDED_SERVICE_EXTENSION_QNAME.equals(unknownNode.getNodeType())) {
+                String prefixAndIdentityLocalName = unknownNode.getNodeParameter();
+                ServiceInterfaceEntry sie = findSIE(prefixAndIdentityLocalName, currentModule, qNamesToSIEs,
+                        schemaContext);
+                result.put(sie.getFullyQualifiedName(), sie.getQName());
+            }
+        }
+        return result;
+    }
+
+    private AttributeIfc getAttributeValue(DataSchemaNode attrNode, Module currentModule,
+            Map<QName, ServiceInterfaceEntry> qNamesToSIEs, TypeProviderWrapper typeProviderWrapper,
+            SchemaContext schemaContext, String packageName) {
+
+        if (attrNode instanceof LeafSchemaNode) {
+            // simple type
+            LeafSchemaNode leaf = (LeafSchemaNode) attrNode;
+            return new JavaAttribute(leaf, typeProviderWrapper);
+        } else if (attrNode instanceof ContainerSchemaNode) {
+            // reference or TO
+            ContainerSchemaNode containerSchemaNode = (ContainerSchemaNode) attrNode;
+            Optional<? extends AbstractDependencyAttribute> dependencyAttributeOptional = extractDependency(
+                    containerSchemaNode, attrNode, currentModule, qNamesToSIEs, schemaContext);
+            if (dependencyAttributeOptional.isPresent()) {
+                return dependencyAttributeOptional.get();
+            } else {
+                return TOAttribute.create(containerSchemaNode, typeProviderWrapper, packageName);
+            }
+
+        } else if (attrNode instanceof LeafListSchemaNode) {
+            return ListAttribute.create((LeafListSchemaNode) attrNode, typeProviderWrapper);
+        } else if (attrNode instanceof ListSchemaNode) {
+            ListSchemaNode listSchemaNode = (ListSchemaNode) attrNode;
+            Optional<? extends AbstractDependencyAttribute> dependencyAttributeOptional = extractDependency(
+                    listSchemaNode, attrNode, currentModule, qNamesToSIEs, schemaContext);
+            if (dependencyAttributeOptional.isPresent()) {
+                return dependencyAttributeOptional.get();
+            } else {
+                return ListAttribute.create(listSchemaNode, typeProviderWrapper, packageName);
+            }
+        } else {
+            throw new UnsupportedOperationException("Unknown configuration node " + attrNode.toString());
+        }
+    }
+
+    private Optional<? extends AbstractDependencyAttribute> extractDependency(DataNodeContainer dataNodeContainer,
+            DataSchemaNode attrNode, Module currentModule, Map<QName, ServiceInterfaceEntry> qNamesToSIEs,
+            SchemaContext schemaContext) {
+        if (dataNodeContainer.getUses().size() == 1 && getChildNodeSizeWithoutUses(dataNodeContainer) == 0) {
+            // reference
+            UsesNode usesNode = dataNodeContainer.getUses().iterator().next();
+            checkState(usesNode.getRefines().size() == 1, "Unexpected 'refine' child node size of " + dataNodeContainer);
+            LeafSchemaNode refine = (LeafSchemaNode) usesNode.getRefines().values().iterator().next();
+            checkState(refine.getUnknownSchemaNodes().size() == 1, "Unexpected unknown schema node size of " + refine);
+            UnknownSchemaNode requiredIdentity = refine.getUnknownSchemaNodes().iterator().next();
+            checkState(ConfigConstants.REQUIRED_IDENTITY_EXTENSION_QNAME.equals(requiredIdentity.getNodeType()),
+                    "Unexpected language extension " + requiredIdentity);
+            String prefixAndIdentityLocalName = requiredIdentity.getNodeParameter();
+            // import should point to a module
+            ServiceInterfaceEntry serviceInterfaceEntry = findSIE(prefixAndIdentityLocalName, currentModule,
+                    qNamesToSIEs, schemaContext);
+            boolean mandatory = refine.getConstraints().isMandatory();
+            AbstractDependencyAttribute reference;
+            if (dataNodeContainer instanceof ContainerSchemaNode) {
+                reference = new DependencyAttribute(attrNode, serviceInterfaceEntry, mandatory,
+                        attrNode.getDescription());
+            } else {
+                reference = new ListDependenciesAttribute(attrNode, serviceInterfaceEntry, mandatory,
+                        attrNode.getDescription());
+            }
+            return Optional.of(reference);
+        }
+        return Optional.absent();
+    }
+
+    private int getChildNodeSizeWithoutUses(DataNodeContainer csn) {
+        int result = 0;
+        for (DataSchemaNode dsn : csn.getChildNodes()) {
+            if (dsn.isAddedByUses() == false) {
+                result++;
+            }
+        }
+        return result;
+    }
+
+    private ServiceInterfaceEntry findSIE(String prefixAndIdentityLocalName, Module currentModule,
+            Map<QName, ServiceInterfaceEntry> qNamesToSIEs, SchemaContext schemaContext) {
+
+        Matcher m = PREFIX_COLON_LOCAL_NAME.matcher(prefixAndIdentityLocalName);
+        Module foundModule;
+        String localSIName;
+        if (m.matches()) {
+            // if there is a prefix, look for ModuleImport with this prefix. Get
+            // Module from SchemaContext
+            String prefix = m.group(1);
+            ModuleImport moduleImport = findModuleImport(currentModule, prefix);
+            foundModule = schemaContext.findModuleByName(moduleImport.getModuleName(), moduleImport.getRevision());
+            checkState(foundModule != null, format("Module not found in SchemaContext by %s", moduleImport));
+            localSIName = m.group(2);
+        } else {
+            foundModule = currentModule; // no prefix => SIE is in currentModule
+            localSIName = prefixAndIdentityLocalName;
+        }
+        QName siQName = new QName(foundModule.getNamespace(), foundModule.getRevision(), localSIName);
+        ServiceInterfaceEntry sie = qNamesToSIEs.get(siQName);
+        checkState(sie != null, "Cannot find referenced Service Interface by " + prefixAndIdentityLocalName);
+        return sie;
+    }
+
+    private ModuleImport findModuleImport(Module module, String prefix) {
+        for (ModuleImport moduleImport : module.getImports()) {
+            if (moduleImport.getPrefix().equals(prefix)) {
+                return moduleImport;
+            }
+        }
+        throw new IllegalStateException(format("Import not found with prefix %s in %s", prefix, module));
+    }
+
+    @VisibleForTesting
+    static Matcher getWhenConditionMatcher(String prefix, RevisionAwareXPath whenConstraint) {
+        String xpathRegex = MODULE_CONDITION_XPATH_TEMPLATE.replace(MAGIC_STRING, prefix);
+        Pattern pattern = Pattern.compile(xpathRegex);
+        return pattern.matcher(whenConstraint.toString());
+    }
+
+    String getConfigModulePrefixFromImport(Module currentModule) {
+        for (ModuleImport currentImport : currentModule.getImports()) {
+            if (currentImport.getModuleName().equals(ConfigConstants.CONFIG_MODULE)) {
+                return currentImport.getPrefix();
+            }
+        }
+        throw new IllegalArgumentException("Cannot find import " + ConfigConstants.CONFIG_MODULE + " in "
+                + currentModule);
+    }
+
+}