Extract pm-dicrionary validation

Issue-ID: VNFSDK-713
Signed-off-by: Pawel <pawel.kasperkiewicz@nokia.com>
Change-Id: Iee5a23a3a6c9215927aa2c453faab62d30453444

18 files changed, 1000 insertions, 0 deletions

diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlFileValidator.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlFileValidator.java
new file mode 100644
index 0000000..2de4f48
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlFileValidator.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml;
+
+import org.onap.validation.yaml.error.SchemaValidationError;
+import org.onap.validation.yaml.error.YamlDocumentValidationError;
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.schema.YamlSchema;
+import org.onap.validation.yaml.schema.YamlSchemaFactory;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class YamlFileValidator {
+
+    private static final int FIRST_DOCUMENT_INDEX = 1;
+
+    public List<YamlDocumentValidationError> validateYamlFileWithSchema(String pathToFile)
+        throws YamlProcessingException {
+
+        List<YamlDocument> documents = new YamlLoader().loadMultiDocumentYamlFile(pathToFile);
+        if(!documents.isEmpty()) {
+            return validateDocuments(documents);
+        } else {
+            throw new YamlProcessingException("PM_Dictionary YAML file is empty");
+        }
+    }
+
+    private List<YamlDocumentValidationError> validateDocuments(List<YamlDocument> documents)
+        throws YamlProcessingException {
+
+        List<YamlDocumentValidationError> yamlFileValidationErrors = new ArrayList<>();
+        YamlSchema schema = extractSchema(documents);
+        YamlValidator validator = new YamlValidator(schema);
+
+        for (int index = FIRST_DOCUMENT_INDEX; index < documents.size(); index++) {
+            List<SchemaValidationError> validationErrors = validator.validate(documents.get(index));
+            yamlFileValidationErrors.addAll(transformErrors(index,validationErrors));
+        }
+
+        return yamlFileValidationErrors;
+    }
+
+    private List<YamlDocumentValidationError> transformErrors(int index, List<SchemaValidationError> validationErrors) {
+        return validationErrors
+            .stream()
+            .map(error->new YamlDocumentValidationError(index, error.getPath(), error.getMessage()))
+            .collect(Collectors.toList());
+    }
+
+    private YamlSchema extractSchema(List<YamlDocument> documents) throws YamlProcessingException {
+        return new YamlSchemaFactory().createTreeStructuredYamlSchema(documents.get(0));
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlLoader.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlLoader.java
new file mode 100644
index 0000000..1a5eef9
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlLoader.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.model.YamlDocumentFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.yaml.snakeyaml.Yaml;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+
+class YamlLoader {
+
+    private static final Logger LOGGER =  LoggerFactory.getLogger(YamlLoader.class);
+
+    List<YamlDocument> loadMultiDocumentYamlFile(URL path)
+        throws YamlDocumentFactory.YamlDocumentParsingException {
+        List<YamlDocument> documentsFromFile = new ArrayList<>();
+        try (InputStream yamlStream = path.openStream()) {
+            for (Object yamlDocument : new Yaml().loadAll(yamlStream)) {
+                documentsFromFile.add(
+                    new YamlDocumentFactory().createYamlDocument(yamlDocument)
+                );
+            }
+        } catch (IOException e) {
+            LOGGER.error("Failed to load multi document YAML file",e);
+        }
+        return documentsFromFile;
+    }
+
+    List<YamlDocument> loadMultiDocumentYamlFile(String path)
+        throws YamlProcessingException {
+        try {
+            return loadMultiDocumentYamlFile(new URL("file://" + path));
+        } catch (MalformedURLException e) {
+            throw new YamlProcessingException("Fail to read file under given path.", e);
+        }
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlValidator.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlValidator.java
new file mode 100644
index 0000000..30ba646
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/YamlValidator.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml;
+
+import org.onap.validation.yaml.error.SchemaValidationError;
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.process.YamlValidationProcess;
+import org.onap.validation.yaml.schema.YamlSchema;
+
+import java.util.List;
+
+public class YamlValidator {
+
+    private final YamlSchema schema;
+
+    YamlValidator(YamlSchema schema) {
+        this.schema = schema;
+    }
+
+    public List<SchemaValidationError> validate(YamlDocument document) throws YamlProcessingException {
+        return new YamlValidationProcess(schema,document).validate();
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/SchemaValidationError.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/SchemaValidationError.java
new file mode 100644
index 0000000..6ffe6d4
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/SchemaValidationError.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.error;
+
+public class SchemaValidationError {
+    private final String path;
+    private final String message;
+
+    public String getPath() {
+        return path;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public SchemaValidationError(String path, String message) {
+        this.path = path;
+        this.message = message;
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/YamlDocumentValidationError.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/YamlDocumentValidationError.java
new file mode 100644
index 0000000..f04708f
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/error/YamlDocumentValidationError.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.error;
+
+public class YamlDocumentValidationError {
+    private final int yamlDocumentNumber;
+    private final String path;
+    private final String message;
+
+    public YamlDocumentValidationError(int yamlDocumentNumber, String path, String message) {
+        this.yamlDocumentNumber = yamlDocumentNumber;
+        this.path = path;
+        this.message = message;
+    }
+
+    public int getYamlDocumentNumber() {
+        return yamlDocumentNumber;
+    }
+
+    public String getPath() {
+        return path;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/exception/YamlProcessingException.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/exception/YamlProcessingException.java
new file mode 100644
index 0000000..99c2437
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/exception/YamlProcessingException.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.exception;
+
+public class YamlProcessingException extends Exception {
+
+    public YamlProcessingException(String message, Throwable throwable) {
+        super(message, throwable);
+    }
+
+    public YamlProcessingException(String message) {
+        super(message);
+    }
+
+    public YamlProcessingException(Throwable throwable) {
+        super(throwable);
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocument.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocument.java
new file mode 100644
index 0000000..557b6fd
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocument.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.model;
+
+import java.util.Map;
+
+public class YamlDocument {
+
+    private final Map<String, Object> yaml;
+
+    YamlDocument(Map<String, Object> yaml) {
+        this.yaml = yaml;
+    }
+
+    public Map<String, Object> getYaml() {
+        return yaml;
+    }
+
+    public boolean containsKey(String key) {
+        return yaml.containsKey(key);
+    }
+
+    public String getValue(String key) {
+        return yaml.get(key).toString();
+    }
+
+    public YamlParametersList getListOfValues(String key) {
+        return new YamlParameterListFactory().createYamlParameterList(
+            yaml.get(key)
+        );
+    }
+
+    public YamlDocument getSubStructure(String name)
+        throws YamlDocumentFactory.YamlDocumentParsingException {
+        return new YamlDocumentFactory().createYamlDocument(
+            yaml.get(name)
+        );
+    }
+}
+
+
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocumentFactory.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocumentFactory.java
new file mode 100644
index 0000000..b56422c
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlDocumentFactory.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.model;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class YamlDocumentFactory {
+
+    public YamlDocument createYamlDocument(Object yaml) throws YamlDocumentParsingException {
+        try {
+            Map<String, Object> parsedYaml = transformMap((Map) yaml);
+            return new YamlDocument(parsedYaml);
+        } catch (ClassCastException e) {
+            throw new YamlDocumentParsingException(
+                String.format("Fail to parse given objects: %s as yaml document.", yaml), e
+            );
+        }
+    }
+
+    private Map<String, Object> transformMap(Map<Object, Object> yaml) {
+        Map<String, Object> parsedYaml = new HashMap<>();
+        for (Map.Entry<Object, Object> entry: yaml.entrySet()) {
+            parsedYaml.put(entry.getKey().toString(), entry.getValue());
+        }
+        return parsedYaml;
+    }
+
+    public static class YamlDocumentParsingException extends YamlProcessingException {
+        YamlDocumentParsingException(String message, Throwable throwable) {
+            super(message, throwable);
+        }
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParameterListFactory.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParameterListFactory.java
new file mode 100644
index 0000000..5f41c5c
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParameterListFactory.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.model;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class YamlParameterListFactory {
+
+    public YamlParametersList createEmptyYamlParameterList() {
+        return new YamlParametersList(Collections.emptyList());
+    }
+
+    public YamlParametersList createYamlParameterList(Object yaml) {
+        List<String> parametersList = new ArrayList<>();
+        if( yaml instanceof List) {
+            for (Object element : (List) yaml) {
+                parametersList.add(element.toString());
+            }
+        } else {
+            parametersList.add(yaml.toString());
+        }
+        return new YamlParametersList(parametersList);
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParametersList.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParametersList.java
new file mode 100644
index 0000000..2b93c74
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/model/YamlParametersList.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.model;
+
+import java.util.List;
+
+public class YamlParametersList {
+
+    private final List<String> parameters;
+
+    YamlParametersList(List<String> parameters) {
+        this.parameters = parameters;
+    }
+
+    public List<String> getParameters() {
+        return parameters;
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationProcess.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationProcess.java
new file mode 100644
index 0000000..ebd37ce
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationProcess.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.process;
+
+import org.onap.validation.yaml.error.SchemaValidationError;
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.schema.YamlSchema;
+import org.onap.validation.yaml.schema.node.YamlSchemaNode;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+public class YamlValidationProcess {
+
+    private final Queue<YamlValidationStep> validationSteps;
+    private final List<SchemaValidationError> errors;
+    private final YamlSchema schema;
+    private final YamlDocument document;
+
+    public YamlValidationProcess(YamlSchema schema, YamlDocument document) {
+        this.schema = schema;
+        this.document = document;
+        errors = new ArrayList<>();
+        validationSteps = new LinkedList<>();
+    }
+
+    public List<SchemaValidationError> validate() throws YamlProcessingException {
+        validationSteps.add(new YamlValidationStep(schema.getRootNodes(), document));
+        while (!validationSteps.isEmpty()) {
+            YamlValidationStep nextValidationNode = validationSteps.poll();
+            validateStep(nextValidationNode);
+        }
+        return errors;
+    }
+
+    private void validateStep(YamlValidationStep validationNode)
+        throws YamlProcessingException {
+        for (YamlSchemaNode schemaNode : validationNode.getSchemaNodes()) {
+            validateNode(validationNode.getDocument(), schemaNode);
+        }
+    }
+
+    private void validateNode(YamlDocument document, YamlSchemaNode schemaNode)
+        throws YamlProcessingException {
+
+        if (document.containsKey(schemaNode.getName())) {
+            if (schemaNode.isContainingSubStructure()) {
+                addNextLevelNodeToValidationNodesQueue(document, schemaNode);
+            } else if (!isValueOfNodeInAcceptedValuesList(document, schemaNode)) {
+                addIncorrectValueError(document, schemaNode);
+            }
+        } else if (schemaNode.isRequired()) {
+            addRequiredKeyNotFoundError(schemaNode);
+        }
+    }
+
+    private boolean isValueOfNodeInAcceptedValuesList(YamlDocument document, YamlSchemaNode node) {
+        return node.getAcceptedValues().isEmpty() ||
+            node.getAcceptedValues().containsAll(
+                document.getListOfValues(node.getName()).getParameters()
+            );
+    }
+
+    private void addNextLevelNodeToValidationNodesQueue(YamlDocument document, YamlSchemaNode node)
+        throws YamlProcessingException {
+        validationSteps.add(
+            new YamlValidationStep(
+                node.getNextNodes(),
+                document.getSubStructure(node.getName())
+            )
+        );
+    }
+
+    private void addRequiredKeyNotFoundError(YamlSchemaNode node) {
+        errors.add(
+            new SchemaValidationError(
+                node.getPath(),
+                String.format("Key not found: %s", node.getName())
+            )
+        );
+    }
+
+    private void addIncorrectValueError(YamlDocument document, YamlSchemaNode node) {
+        errors.add(
+            new SchemaValidationError(
+                node.getPath() + node.getName(),
+                String.format(
+                    "Value(s) is/are not in array of accepted values.%n value(s):  %s%n  accepted value(s):  %s",
+                    document.getValue(node.getName()), node.getAcceptedValues())
+            )
+        );
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationStep.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationStep.java
new file mode 100644
index 0000000..eb5ab8e
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/process/YamlValidationStep.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.process;
+
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.schema.node.YamlSchemaNode;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+class YamlValidationStep {
+
+    private final List<YamlSchemaNode> schemaNodes;
+    private final YamlDocument document;
+
+    YamlValidationStep(List<YamlSchemaNode> nodes, YamlDocument yaml) {
+        this.schemaNodes = new ArrayList<>(nodes);
+        this.document = yaml;
+    }
+
+    List<YamlSchemaNode> getSchemaNodes() {
+        return Collections.unmodifiableList(schemaNodes);
+    }
+
+    YamlDocument getDocument() {
+        return document;
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchema.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchema.java
new file mode 100644
index 0000000..69bb6cd
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchema.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.schema;
+
+import org.onap.validation.yaml.schema.node.YamlSchemaNode;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class YamlSchema {
+
+    private final List<YamlSchemaNode> rootNodes;
+
+    public List<YamlSchemaNode> getRootNodes() {
+        return Collections.unmodifiableList(rootNodes);
+    }
+
+    YamlSchema(List<YamlSchemaNode> rootNodes) {
+        this.rootNodes = new ArrayList<>(rootNodes);
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchemaFactory.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchemaFactory.java
new file mode 100644
index 0000000..df7d673
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/YamlSchemaFactory.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+
+package org.onap.validation.yaml.schema;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.model.YamlDocumentFactory;
+import org.onap.validation.yaml.schema.node.YamlSchemaNode;
+import org.onap.validation.yaml.schema.node.YamlSchemaNodeFactory;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class YamlSchemaFactory {
+
+
+    private static final String ROOT_PATH = "/";
+
+    public YamlSchema createTreeStructuredYamlSchema(YamlDocument schema)
+        throws YamlProcessingException {
+
+        return new YamlSchema(getRootNodes(schema));
+    }
+
+    private List<YamlSchemaNode> getRootNodes(YamlDocument yamlDocument)
+        throws YamlProcessingException {
+
+        List<YamlSchemaNode> nextNodes = new ArrayList<>();
+        for(String nodeName: yamlDocument.getYaml().keySet()) {
+            nextNodes.add(
+                new YamlSchemaNodeFactory().createNode(
+                    nodeName,
+                    ROOT_PATH,
+                    new YamlDocumentFactory().createYamlDocument(
+                        yamlDocument.getYaml().get(nodeName)
+                    )
+                )
+            );
+        }
+        return nextNodes;
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaBranchNode.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaBranchNode.java
new file mode 100644
index 0000000..0f5b480
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaBranchNode.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.schema.node;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.model.YamlDocumentFactory;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+public class YamlSchemaBranchNode extends YamlSchemaNode {
+
+    private final YamlDocument nextNodesInLazyForm;
+    private Optional<List<YamlSchemaNode>> nextNodes;
+
+    YamlSchemaBranchNode(String name, String path, boolean required, String comment,
+                         YamlDocument nextNodesInLazyForm) {
+        super(name, path, required, comment);
+        this.nextNodesInLazyForm = nextNodesInLazyForm;
+        this.nextNodes = Optional.empty();
+    }
+
+    @Override
+    public boolean isContainingSubStructure() {
+        return true;
+    }
+
+    @Override
+    public List<String> getAcceptedValues() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public synchronized List<YamlSchemaNode> getNextNodes() throws YamlSchemaProcessingException {
+        try {
+            return nextNodes.orElseGet(this::loadNextNodes);
+        } catch (YamlSchemaLazyLoadingException lazyLoadingException) {
+            throw new YamlSchemaProcessingException(lazyLoadingException);
+        }
+    }
+
+    private List<YamlSchemaNode> loadNextNodes() {
+        try {
+            List<YamlSchemaNode> loadedNextNodes = new ArrayList<>();
+            for (String key : nextNodesInLazyForm.getYaml().keySet()) {
+                YamlDocument substructure = new YamlDocumentFactory()
+                    .createYamlDocument(nextNodesInLazyForm.getYaml().get(key));
+                loadedNextNodes.add(new YamlSchemaNodeFactory().createNode(key, getPath() + getName() + "/", substructure));
+            }
+            nextNodes = Optional.of(loadedNextNodes);
+            return loadedNextNodes;
+        } catch (YamlProcessingException e) {
+            throw new YamlSchemaLazyLoadingException("Lazy loading failed, due to yaml parsing exception.",e);
+        }
+    }
+
+    static class YamlSchemaLazyLoadingException extends RuntimeException {
+        YamlSchemaLazyLoadingException(String message, Throwable throwable) {
+            super(message, throwable);
+        }
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaLeafNode.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaLeafNode.java
new file mode 100644
index 0000000..c98f41e
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaLeafNode.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.schema.node;
+
+import org.onap.validation.yaml.model.YamlParametersList;
+
+import java.util.Collections;
+import java.util.List;
+
+public class YamlSchemaLeafNode extends YamlSchemaNode {
+
+    private final YamlParametersList acceptedValues;
+
+    YamlSchemaLeafNode(String name, String path, boolean required, String comment,
+                       YamlParametersList acceptedValues) {
+        super(name, path, required, comment);
+        this.acceptedValues = acceptedValues;
+    }
+
+    @Override
+    public List<String> getAcceptedValues() {
+        return acceptedValues.getParameters();
+    }
+
+    @Override
+    public List<YamlSchemaNode> getNextNodes() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public boolean isContainingSubStructure() {
+        return false;
+    }
+
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNode.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNode.java
new file mode 100644
index 0000000..28913a2
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNode.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.schema.node;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+
+import java.util.List;
+
+public abstract class YamlSchemaNode {
+
+    private final String path;
+    private final String name;
+    private final boolean required;
+    private final String comment;
+
+
+    public String getName() {
+        return name;
+    }
+
+    public String getPath() {
+        return path;
+    }
+
+    public boolean isRequired() {
+        return required;
+    }
+
+    public abstract List<String> getAcceptedValues();
+
+    public abstract List<YamlSchemaNode> getNextNodes() throws YamlSchemaProcessingException;
+
+    public abstract boolean isContainingSubStructure();
+
+    public String getComment() {
+        return comment;
+    }
+
+    YamlSchemaNode(String name, String path, boolean required, String comment) {
+        this.name = name;
+        this.path = path;
+        this.required = required;
+        this.comment = comment;
+    }
+
+    static class YamlSchemaProcessingException extends YamlProcessingException {
+        YamlSchemaProcessingException(Throwable throwable) {
+            super(throwable);
+        }
+    }
+}
diff --git a/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNodeFactory.java b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNodeFactory.java
new file mode 100644
index 0000000..79a8f14
--- /dev/null
+++ b/pmdictionaryvalidation/src/main/java/org/onap/validation/yaml/schema/node/YamlSchemaNodeFactory.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onap.validation.yaml.schema.node;
+
+import org.onap.validation.yaml.exception.YamlProcessingException;
+import org.onap.validation.yaml.model.YamlDocument;
+import org.onap.validation.yaml.model.YamlDocumentFactory;
+import org.onap.validation.yaml.model.YamlParameterListFactory;
+import org.onap.validation.yaml.model.YamlParametersList;
+
+import static org.onap.validation.yaml.model.YamlDocumentFactory.YamlDocumentParsingException;
+
+public class YamlSchemaNodeFactory {
+
+    public static final String EMPTY_COMMENT = "no comment available";
+    static final String STRUCTURE_KEY = "structure";
+    static final String COMMENT_KEY = "comment";
+    static final String VALUE_KET = "value";
+    static final String PRESENCE_KEY = "presence";
+    static final String PRESENCE_REQUIRED_KEY = "required";
+
+    public YamlSchemaNode createNode(String nodeName, String path, YamlDocument yamlDocument)
+        throws YamlProcessingException {
+
+        YamlSchemaNode yamlSchemaNode;
+        if(isYamlContainingKey(yamlDocument, STRUCTURE_KEY)) {
+            yamlSchemaNode = new YamlSchemaBranchNode(
+                nodeName, path, getIsPresenceRequired(yamlDocument), getComment(yamlDocument),
+                getNextNodes(yamlDocument)
+            );
+        } else {
+            yamlSchemaNode = new YamlSchemaLeafNode(
+                nodeName, path, getIsPresenceRequired(yamlDocument), getComment(yamlDocument),
+                getAcceptedValues(yamlDocument)
+            );
+        }
+        return  yamlSchemaNode;
+    }
+
+    private YamlDocument getNextNodes(YamlDocument yamlDocument)
+        throws YamlDocumentParsingException {
+        return new YamlDocumentFactory().createYamlDocument(yamlDocument.getYaml().get(STRUCTURE_KEY));
+    }
+
+    private String getComment(YamlDocument yamlDocument) {
+
+        return isYamlContainingKey(yamlDocument, COMMENT_KEY)
+            ? yamlDocument.getYaml().get(COMMENT_KEY).toString()
+            : EMPTY_COMMENT;
+    }
+
+    private YamlParametersList getAcceptedValues(YamlDocument yamlDocument) {
+
+        return isYamlContainingKey(yamlDocument, VALUE_KET)
+            ? new YamlParameterListFactory().createYamlParameterList(yamlDocument.getYaml().get(VALUE_KET))
+            : new YamlParameterListFactory().createEmptyYamlParameterList();
+    }
+
+    private boolean getIsPresenceRequired(YamlDocument yamlDocument) {
+
+        return isYamlContainingKey(yamlDocument, PRESENCE_KEY)
+            && yamlDocument.getYaml().get(PRESENCE_KEY).equals(PRESENCE_REQUIRED_KEY);
+    }
+
+    private boolean isYamlContainingKey(YamlDocument yamlDocument, String structureKey) {
+        return yamlDocument.getYaml().containsKey(structureKey);
+    }
+
+}