Merge of new rebased code

Change-Id: I9b8d1f69eb3e0af1935ed8304fea4bf54c1aac47
Signed-off-by: Patrick Brady <pb071s@att.com>

22 files changed, 1409 insertions, 0 deletions

diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyManager.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyManager.java
new file mode 100644
index 000000000..5b5b3451b
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyManager.java
@@ -0,0 +1,33 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager;
+
+import org.openecomp.appc.dg.dependencymanager.exception.DependencyModelNotFound;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.objects.DependencyTypes;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+
+import org.openecomp.appc.metadata.objects.DependencyModelIdentifier;
+
+public interface DependencyManager {
+    VnfcDependencyModel getVnfcDependencyModel(DependencyModelIdentifier modelIdentifier, DependencyTypes dependencyType) throws InvalidDependencyModel, DependencyModelNotFound;
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyType.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyType.java
new file mode 100644
index 000000000..06a29cd1d
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/DependencyType.java
@@ -0,0 +1,32 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager;
+
+import org.openecomp.appc.dg.dependencymanager.exception.DependencyModelNotFound;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+
+import org.openecomp.appc.metadata.objects.DependencyModelIdentifier;
+
+public interface DependencyType {
+    VnfcDependencyModel getVnfcDependencyModel(DependencyModelIdentifier modelIdentifier) throws InvalidDependencyModel, DependencyModelNotFound;
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/exception/DependencyModelNotFound.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/exception/DependencyModelNotFound.java
new file mode 100644
index 000000000..521e0edb3
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/exception/DependencyModelNotFound.java
@@ -0,0 +1,29 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager.exception;
+
+
+public class DependencyModelNotFound extends Exception {
+    public DependencyModelNotFound(String message){
+        super(message);
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/helper/DependencyModelParser.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/helper/DependencyModelParser.java
new file mode 100644
index 000000000..397042ecd
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/helper/DependencyModelParser.java
@@ -0,0 +1,183 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager.helper;
+
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import org.apache.commons.lang3.StringUtils;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.objects.Node;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+import org.openecomp.appc.domainmodel.Vnfc;
+
+import java.io.IOException;
+import java.util.*;
+
+
+public class DependencyModelParser {
+
+    private static final EELFLogger logger = EELFManager.getInstance().getLogger(DependencyModelParser.class);
+    private static Map<String, String> dependencyMap;
+    private static final String PROPERTIES = "properties";
+    private static final String ACTIVE_ACTIVE = "Active-Active";
+    private static final String ACTIVE_PASSIVE = "Active-Passive";
+    private static final String HIGH_AVAILABLITY = "high_availablity";
+    private static final String MANDATORY = "mandatory";
+    private static final String TOPOLOGY_TEMPLATE = "topology_template";
+
+    static {
+        Map<String, String> dependencyTypeMappingMap =new HashMap<>();
+        dependencyTypeMappingMap.put("geo-activeactive", ACTIVE_ACTIVE);
+        dependencyTypeMappingMap.put("geo-activestandby", ACTIVE_PASSIVE);
+        dependencyTypeMappingMap.put("local-activeactive", ACTIVE_ACTIVE);
+        dependencyTypeMappingMap.put("local-activestandby", ACTIVE_PASSIVE);
+        dependencyMap = Collections.unmodifiableMap(dependencyTypeMappingMap);
+    }
+
+    public VnfcDependencyModel generateDependencyModel(String vnfModel,String vnfType) {
+        Set<Node<Vnfc>> dependencies = new HashSet<>();
+        ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
+        boolean mandatory;
+        String resilienceType;
+        String prefix = "org.openecomp.resource.vfc."+vnfType+".abstract.nodes.";
+        try {
+            ObjectNode root = (ObjectNode) mapper.readTree(vnfModel);
+            logger.debug("VNF Model after parsing: " + root);
+
+            if(root.get(TOPOLOGY_TEMPLATE) == null || root.get(TOPOLOGY_TEMPLATE).get("node_templates") == null) {
+                throw new InvalidDependencyModel("Dependency model is missing 'topology_template' or  'node_templates' elements");
+            }
+
+            JsonNode topologyTemplateNode = root.get(TOPOLOGY_TEMPLATE);
+            JsonNode nodeTemplateNode = topologyTemplateNode.get("node_templates");
+            Iterator<Map.Entry<String, JsonNode>> itretor  = nodeTemplateNode.fields();
+            for (JsonNode yamlNode : nodeTemplateNode) {
+                logger.debug("Processing node: " + yamlNode);
+                String vnfcType = itretor.next().getKey();
+                String type = yamlNode.get("type").textValue();
+                type = type.substring(0,type.lastIndexOf(".")+1);
+                if(type.concat(vnfcType).toLowerCase().startsWith(prefix.concat(vnfcType).toLowerCase())) {
+
+                    if(yamlNode.get(PROPERTIES).findValue(HIGH_AVAILABLITY) == null || yamlNode.get(PROPERTIES).findValue(HIGH_AVAILABLITY).asText().isEmpty()) {
+                        resilienceType = ACTIVE_ACTIVE;
+                    }else {
+                        resilienceType = dependencyMap.get(yamlNode.get(PROPERTIES).findValue(HIGH_AVAILABLITY).textValue());
+                    }
+
+                    if(yamlNode.get(PROPERTIES).findValue(MANDATORY) == null || yamlNode.get(PROPERTIES).findValue(MANDATORY).asText().isEmpty()) {
+                        mandatory = false;
+                    }else {
+                        mandatory = yamlNode.get(PROPERTIES).findValue(MANDATORY).booleanValue();
+                    }
+                    String[] parentList = getDependencyArray(yamlNode);
+                    Node<Vnfc> vnfcNode = getNode(dependencies, vnfcType);
+                    if (vnfcNode != null) {
+                        logger.debug("Dependency node already exists for vnfc Type: " + vnfcType);
+                        if (StringUtils.isEmpty(vnfcNode.getChild().getResilienceType())) {
+                            logger.debug("Updating resilience type, dependencies and mandatory attribute for VNFC type: " + vnfcType);
+                            vnfcNode.getChild().setResilienceType(resilienceType);
+                            if (parentList != null && parentList.length > 0) {
+                                addDependencies(dependencies, vnfcNode, parentList);
+                            }
+                            vnfcNode.getChild().setMandatory(mandatory);
+                        }
+
+                    } else {
+                        logger.debug("Creating dependency node for  : " + vnfcType);
+                        vnfcNode = new Node<>(new Vnfc(vnfcType, resilienceType, null, mandatory));
+                        if (parentList != null && parentList.length > 0)
+                            addDependencies(dependencies, vnfcNode, parentList);
+                        logger.debug("Adding VNFC to dependency model : " + vnfcNode);
+                        dependencies.add(vnfcNode);
+                    }
+                }
+            }
+        } catch (IOException e) {
+            logger.error("Error parsing dependency model : " + vnfModel);
+            logger.error("Error message : " + e);
+            throw new InvalidDependencyModel("Error parsing dependency model. " + e.getMessage());
+        }
+        return new VnfcDependencyModel(dependencies);
+    }
+
+    private void addDependencies(Set<Node<Vnfc>> nodes, Node node, String[] parentList) {
+        for (String type : parentList) {
+            String parentType = getVnfcType(type);
+            Node<Vnfc> parentNode = getNode(nodes, parentType);
+            if (parentNode != null) {
+                logger.debug("VNFC already exists for VNFC type: " + parentType + ". Adding it to parent list ");
+                node.addParent(parentNode.getChild());
+            } else {
+                logger.debug("VNFC does not exist for VNFC type: " + parentType + ". Creating new VNFC ");
+                parentNode = new Node<>(new Vnfc(parentType, null));
+                node.addParent(parentNode.getChild());
+                logger.debug("Adding VNFC to dependency model : " + parentNode);
+                nodes.add(parentNode);
+            }
+        }
+    }
+
+    private String[] getDependencyArray(JsonNode node) {
+        JsonNode requirementsNode = node.get("requirements");
+        List<String> dependencyList  = new ArrayList();
+        if(requirementsNode!=null) {
+            for (JsonNode internalNode : requirementsNode) {
+                if (nodeNullCheck(internalNode) &&"tosca.capabilities.Node".equalsIgnoreCase(internalNode.get("capability").asText())
+                        && "tosca.relationships.DependsOn".equalsIgnoreCase(internalNode.get("relationship").asText())) {
+                    if(internalNode.get("node") != null) {
+                        dependencyList.add(internalNode.get("node").asText());
+                    }else{
+                        throw new InvalidDependencyModel("Error parsing dependency model. " + "Dependent Node not found for "+ node.get("type"));
+                    }
+                }
+            }
+            return  dependencyList.toArray(new String[0]);
+        }else{
+            return new String[0];
+        }
+    }
+
+    private boolean nodeNullCheck(JsonNode internalNode) {
+        return internalNode.get("dependency") != null && internalNode.get("capability") != null && internalNode.get("relationship") != null;
+    }
+
+    private Node<Vnfc> getNode(Set<Node<Vnfc>> nodes, String vnfcType) {
+        Iterator itr = nodes.iterator();
+        Node<Vnfc> node;
+        while (itr.hasNext()) {
+            node = (Node<Vnfc>) itr.next();
+            if (node.getChild().getVnfcType().equalsIgnoreCase(vnfcType)) {
+                return node;
+            }
+        }
+        return null;
+    }
+
+    private String getVnfcType(String type) {
+        return type.substring(type.lastIndexOf('.') + 1, type.length());
+    }
+
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyManagerImpl.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyManagerImpl.java
new file mode 100644
index 000000000..758d5ee7e
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyManagerImpl.java
@@ -0,0 +1,71 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager.impl;
+
+import org.openecomp.appc.dg.dependencymanager.DependencyManager;
+import org.openecomp.appc.dg.dependencymanager.DependencyType;
+import org.openecomp.appc.dg.dependencymanager.exception.DependencyModelNotFound;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.objects.DependencyTypes;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+
+import org.openecomp.appc.cache.MetadataCache;
+import org.openecomp.appc.cache.impl.MetadataCacheFactory;
+import org.openecomp.appc.metadata.objects.DependencyModelIdentifier;
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+
+public class DependencyManagerImpl implements DependencyManager {
+
+    private static final EELFLogger logger = EELFManager.getInstance().getLogger(DependencyManagerImpl.class);
+
+    MetadataCache<DependencyModelIdentifier,VnfcDependencyModel> cache;
+
+    DependencyManagerImpl(){
+        cache = MetadataCacheFactory.getInstance().getMetadataCache();
+    }
+
+    public VnfcDependencyModel getVnfcDependencyModel(DependencyModelIdentifier modelIdentifier,DependencyTypes dependencyType) throws InvalidDependencyModel, DependencyModelNotFound {
+        if (logger.isTraceEnabled()) {
+            logger.trace("Entering to getVnfcDependencyModel with DependencyModelIdentifier = "+ modelIdentifier
+                    + " , DependencyTypes = " + dependencyType);
+        }
+        VnfcDependencyModel dependencyModel = cache.getObject(modelIdentifier);
+        if(dependencyModel == null){
+            logger.debug("Dependency model not found in cache, creating strategy for reading it");
+            DependencyType strategy = getStrategy(dependencyType);
+            dependencyModel = strategy.getVnfcDependencyModel(modelIdentifier);
+        }
+        if (logger.isTraceEnabled()) {
+            logger.trace("Returning getVnfcDependencyModel with dependency model = "+ dependencyModel);
+        }
+        return dependencyModel;
+    }
+
+    private DependencyType getStrategy(DependencyTypes dependencyType) {
+        switch (dependencyType){
+            case RESOURCE:
+                return new ResourceDependency();
+        }
+        return null;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyModelFactory.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyModelFactory.java
new file mode 100644
index 000000000..87bdd32fa
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/DependencyModelFactory.java
@@ -0,0 +1,37 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager.impl;
+
+import org.openecomp.appc.dg.dependencymanager.DependencyManager;
+
+
+public class DependencyModelFactory {
+
+    private static class ReferenceHolder{
+        private static final DependencyManagerImpl INSTANCE = new DependencyManagerImpl();
+    }
+
+    public static DependencyManager createDependencyManager(){
+        return ReferenceHolder.INSTANCE;
+    }
+
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/ResourceDependency.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/ResourceDependency.java
new file mode 100644
index 000000000..0cb9eebb4
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/dependencymanager/impl/ResourceDependency.java
@@ -0,0 +1,83 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.dependencymanager.impl;
+
+import org.openecomp.appc.metadata.MetadataService;
+import org.openecomp.appc.metadata.objects.DependencyModelIdentifier;
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+
+import org.openecomp.appc.dg.dependencymanager.DependencyType;
+import org.openecomp.appc.dg.dependencymanager.exception.DependencyModelNotFound;
+import org.openecomp.appc.dg.dependencymanager.helper.DependencyModelParser;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.FrameworkUtil;
+import org.osgi.framework.ServiceReference;
+
+
+public class ResourceDependency implements DependencyType{
+
+    private static final EELFLogger logger = EELFManager.getInstance().getLogger(ResourceDependency.class);
+
+
+    private MetadataService metadataService;
+
+    public ResourceDependency(){
+        getMetadataServiceRef();
+    }
+
+    private void getMetadataServiceRef() {
+        BundleContext bctx = FrameworkUtil.getBundle(MetadataService.class).getBundleContext();
+        // Get MetadataService reference
+        ServiceReference sref = bctx.getServiceReference(MetadataService.class.getName());
+        if (sref != null) {
+            logger.info("MetadataService from bundlecontext");
+            metadataService = (MetadataService) bctx.getService(sref);
+
+        } else {
+            logger.info("MetadataService error from bundlecontext");
+            logger.warn("Cannot find service reference for org.openecomp.appc.metadata.MetadataService");
+        }
+    }
+
+    public void setMetadataService(MetadataService metadataService) {
+        this.metadataService = metadataService;
+    }
+
+    public VnfcDependencyModel getVnfcDependencyModel(DependencyModelIdentifier modelIdentifier) throws InvalidDependencyModel, DependencyModelNotFound {
+        if (logger.isTraceEnabled()) {
+            logger.trace("Entering to getVnfcDependencyModel with DependencyModelIdentifier = "+ modelIdentifier);
+        }
+        String vnfModel = metadataService.getVnfModel(modelIdentifier);
+        if(vnfModel ==null){
+            logger.debug("Vnf model not found from metadata service");
+            throw new DependencyModelNotFound("Invalid or Empty VNF Model");
+        }
+        if (logger.isTraceEnabled()) {
+            logger.trace("Building dependency model for Vnf Model : " + vnfModel);
+        }
+        DependencyModelParser modelParser = new DependencyModelParser();
+        return modelParser.generateDependencyModel(vnfModel,modelIdentifier.getVnfType());
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowBuilder.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowBuilder.java
new file mode 100644
index 000000000..6b87e6621
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowBuilder.java
@@ -0,0 +1,31 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder;
+
+import org.openecomp.appc.dg.objects.InventoryModel;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+import org.openecomp.appc.dg.objects.VnfcFlowModel;
+
+
+public interface FlowBuilder {
+    VnfcFlowModel buildFlowModel(VnfcDependencyModel dependencyModel,InventoryModel inventoryModel);
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowStrategy.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowStrategy.java
new file mode 100644
index 000000000..3c3488f70
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/FlowStrategy.java
@@ -0,0 +1,32 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder;
+
+import org.openecomp.appc.dg.objects.InventoryModel;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+import org.openecomp.appc.dg.objects.VnfcFlowModel;
+
+
+public interface FlowStrategy {
+
+    VnfcFlowModel buildFlowModel(VnfcDependencyModel dependencyModel, InventoryModel inventoryModel);
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/exception/InvalidDependencyModel.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/exception/InvalidDependencyModel.java
new file mode 100644
index 000000000..8bec80a47
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/exception/InvalidDependencyModel.java
@@ -0,0 +1,29 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.exception;
+
+
+public class InvalidDependencyModel extends RuntimeException {
+    public InvalidDependencyModel(String message){
+        super(message);
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/helper/Graph.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/helper/Graph.java
new file mode 100644
index 000000000..b9115187c
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/helper/Graph.java
@@ -0,0 +1,64 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.helper;
+
+import java.util.*;
+
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+
+
+public class Graph<T> {
+    private int size;
+    private List<T> vertexList;
+
+    private int[][] dependencyMatrix;
+
+    public Graph(int size){
+        this.size =size;
+        vertexList = new ArrayList<>();
+        dependencyMatrix = new int[size][size];
+    }
+
+    public void addVertex(T vertex){
+        vertexList.add(vertex);
+    }
+
+    public int getIndex(T vertex){
+        return vertexList.indexOf(vertex);
+    }
+
+    public void addEdge(T vertex1,T vertex2){
+        dependencyMatrix[vertexList.indexOf(vertex1)][vertexList.indexOf(vertex2)] = 1;
+    }
+
+    public int[][] getDependencyMatrix() {
+        return dependencyMatrix;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public List<T> getVertexList() {
+        return vertexList;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/AbstractFlowStrategy.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/AbstractFlowStrategy.java
new file mode 100644
index 000000000..15ff20083
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/AbstractFlowStrategy.java
@@ -0,0 +1,133 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.impl;
+
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+import org.openecomp.appc.dg.flowbuilder.FlowStrategy;
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.dg.flowbuilder.helper.Graph;
+import org.openecomp.appc.dg.objects.*;
+import org.openecomp.appc.domainmodel.Vnfc;
+
+
+public abstract class AbstractFlowStrategy implements FlowStrategy {
+
+    protected Graph<Vnfc> graph;
+
+    private static final EELFLogger logger = EELFManager.getInstance().getLogger(AbstractFlowStrategy.class);
+
+    public VnfcFlowModel buildFlowModel(VnfcDependencyModel dependencyModel, InventoryModel inventoryModel) {
+        if(logger.isTraceEnabled()){
+            logger.trace("Entering into buildFlowModel with dependency model = " + dependencyModel
+                    + "inventory model = " +inventoryModel);
+        }
+
+        if(dependencyModel == null
+                || dependencyModel.getDependencies() ==null
+                || dependencyModel.getDependencies().size() ==0){
+            logger.debug("Dependency model not available, building flow model with sequence");
+            throw new InvalidDependencyModel("Dependency model either null or does not contain any dependency");
+        }
+
+        VnfcFlowModel flowModel = buildFlowModel(dependencyModel);
+        if(logger.isDebugEnabled()){
+            logger.debug("Flow Model without instance data: \n" + flowModel);
+        }
+
+        logger.info("Populating flow model with A&AI data");
+        populateFlowModel(flowModel,inventoryModel);
+        if(logger.isDebugEnabled()){
+            logger.debug("Flow Model with instance data: \n" + flowModel);
+        }
+
+        return flowModel;
+    }
+
+    private void populateFlowModel(VnfcFlowModel flowModel, InventoryModel inventoryModel) {
+        Iterator<List<Vnfc>> flowIterator = null;
+
+        for(Vnfc vnfcFromInventory:inventoryModel.getVnf().getVnfcs()){
+            flowIterator = flowModel.getModelIterator();
+            String vnfcType = vnfcFromInventory.getVnfcType();
+            while (flowIterator.hasNext()){
+                for(Vnfc vnfcFromFlowModel:flowIterator.next() ){
+                    if(vnfcType.equalsIgnoreCase(vnfcFromFlowModel.getVnfcType())){
+                        vnfcFromFlowModel.setVnfcName(vnfcFromInventory.getVnfcName());
+                        vnfcFromFlowModel.addVms(vnfcFromInventory.getVserverList());
+                    }
+                }
+            }
+
+        }
+
+    }
+
+    private VnfcFlowModel buildFlowModel(VnfcDependencyModel dependencyModel) throws InvalidDependencyModel {
+        Set<Node<Vnfc>> dependencies = dependencyModel.getDependencies();
+        graph = new Graph(dependencies.size());
+
+        for(Node<Vnfc> node:dependencies){
+            graph.addVertex(node.getChild());
+        }
+
+        for(Node node:dependencies){
+            Vnfc child = (Vnfc)node.getChild();
+            List<Vnfc> parents = node.getParents();
+            for(Vnfc parent:parents){
+                graph.addEdge(child,parent);
+            }
+        }
+        List<List<Vnfc>> dependencyList = orderDependencies();
+
+        VnfcFlowModel.VnfcFlowModelBuilder builder = new VnfcFlowModel.VnfcFlowModelBuilder();
+        int count=0;
+        int flowModelSize = 0;
+        for(List<Vnfc> vnfcList:dependencyList){
+            builder.addMetadata(count,vnfcList);
+            flowModelSize += vnfcList.size();
+            count++;
+        }
+        if(flowModelSize != dependencies.size()){
+            throw new InvalidDependencyModel("Cycle detected in the VNFC dependencies");
+        }
+
+        return builder.build();
+    }
+
+    protected abstract List<List<Vnfc>> orderDependencies();
+
+    /*private VnfcFlowModel buildFlowModelWithoutSequence(InventoryModel inventoryModel) {
+        VnfcFlowModel.VnfcFlowModelBuilder builder = new VnfcFlowModel.VnfcFlowModelBuilder();
+
+        for(Vnfc vnfc:inventoryModel.getVnf().getVnfcs()){
+            builder = builder.addMetadata(0,vnfc);
+        }
+
+        return builder.build();
+    }*/
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderFactory.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderFactory.java
new file mode 100644
index 000000000..7b9759852
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderFactory.java
@@ -0,0 +1,48 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.impl;
+
+import org.openecomp.appc.dg.flowbuilder.FlowBuilder;
+import org.openecomp.appc.dg.objects.FlowStrategies;
+
+
+public class FlowBuilderFactory {
+    private static class ReferenceHolder{
+        private static final FlowBuilderFactory FACTORY = new FlowBuilderFactory();
+    }
+
+    public static FlowBuilderFactory getInstance(){
+        return ReferenceHolder.FACTORY;
+    }
+
+    public FlowBuilder getFlowBuilder(FlowStrategies flowStrategy){
+
+        switch (flowStrategy){
+            case FORWARD:
+                    return new FlowBuilderImpl(new ForwardFlowStrategy());
+            case REVERSE:
+                return new FlowBuilderImpl(new ReverseFlowStrategy());
+        }
+        return null;
+
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderImpl.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderImpl.java
new file mode 100644
index 000000000..80bd3eec2
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/FlowBuilderImpl.java
@@ -0,0 +1,49 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.impl;
+
+import org.openecomp.appc.dg.flowbuilder.FlowBuilder;
+import org.openecomp.appc.dg.flowbuilder.FlowStrategy;
+import org.openecomp.appc.dg.objects.InventoryModel;
+import org.openecomp.appc.dg.objects.VnfcDependencyModel;
+import org.openecomp.appc.dg.objects.VnfcFlowModel;
+
+import com.att.eelf.configuration.EELFLogger;
+import com.att.eelf.configuration.EELFManager;
+
+
+public class FlowBuilderImpl implements FlowBuilder {
+
+
+
+    private FlowStrategy strategy;
+
+    FlowBuilderImpl(FlowStrategy strategy){
+        this.strategy = strategy;
+    }
+
+    public VnfcFlowModel buildFlowModel(VnfcDependencyModel dependencyModel, InventoryModel inventoryModel) {
+        return strategy.buildFlowModel(dependencyModel, inventoryModel);
+    }
+
+
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ForwardFlowStrategy.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ForwardFlowStrategy.java
new file mode 100644
index 000000000..486e942a7
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ForwardFlowStrategy.java
@@ -0,0 +1,114 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.impl;
+
+import java.util.*;
+
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.domainmodel.Vnfc;
+
+
+public class ForwardFlowStrategy extends AbstractFlowStrategy {
+    @Override
+    protected List<List<Vnfc>> orderDependencies() {
+        ArrayList<List<Vnfc>> arrayList = new ArrayList<>();
+
+        Queue<Vnfc> queue1 = new LinkedList();
+        Set<Vnfc> queue2 = new LinkedHashSet<>();
+
+        Set<Vnfc> uniqueElementSet = new HashSet<>();
+        Set<Vnfc> duplicateElementSet = new HashSet<>();
+
+        // identifying independent nodes in queue1
+        for(int rowIndex=0;rowIndex<graph.getSize();rowIndex++){
+            Integer sum = 0;
+            for(int colIndex=0;colIndex<graph.getSize();colIndex++){
+                sum+= graph.getDependencyMatrix()[rowIndex][colIndex];
+            }
+            if(sum==0){
+                Vnfc vnfc = graph.getVertexList().get(rowIndex);
+                queue1.add(vnfc);
+            }
+        }
+        if(queue1.isEmpty()){
+            throw new InvalidDependencyModel("There seems to be no Root/Independent node for Vnfc dependencies");
+        }
+        arrayList.add((List<Vnfc>)queue1);
+        queue1 = new LinkedList<>(queue1);
+
+        boolean flag = true;
+
+        while(flag){
+            // iterating over queue1 and for each node in it finding all dependent nodes and putting them on queue2
+            while(!queue1.isEmpty()){
+                Vnfc listItem = queue1.remove();
+                Integer colIndex = graph.getIndex(listItem);
+                for(Integer index =0;index<graph.getSize();index++){
+                    Integer value = graph.getDependencyMatrix()[index][colIndex];
+                    if(value ==1){
+                        Vnfc vnfc = graph.getVertexList().get(index);
+                        queue2.add(vnfc);
+                    }
+                }
+            }
+            for(Vnfc vnfc:queue2){
+                if(!uniqueElementSet.add(vnfc)){
+                    duplicateElementSet.add(vnfc);
+                }
+            }
+            if(queue2.isEmpty()){
+                flag= false; // empty queue2 indicates that all leaf nodes have been identified, i.e. stop the iteration
+            }
+            else{
+                arrayList.add(new ArrayList<Vnfc>(queue2));
+                if(arrayList.size()>graph.getSize()){
+                    // dependency list cannot be larger than total number of nodes
+                    // if it happens indicates cycle in the dependency
+                    throw new InvalidDependencyModel("Cycle detected in the VNFC dependencies");
+                }
+                queue1.addAll(queue2);
+                queue2 = new LinkedHashSet<>();
+            }
+        }
+        // If any node depends on multiple nodes present in different execution sequence,
+        // its execution should happen on the higher order, removing its presence on lower execution sequence
+        if(!duplicateElementSet.isEmpty()){
+            for(Vnfc vnfc:duplicateElementSet){
+                boolean firstOccurrence= true;
+                for(int i=arrayList.size()-1;i>=0;i--){
+                    List<Vnfc> list = arrayList.get(i);
+                    if(list.contains(vnfc)){
+                        if(firstOccurrence){
+                            firstOccurrence =false;
+                            continue;
+                        }
+                        else{
+                            list.remove(vnfc);
+                        }
+                    }
+
+                }
+            }
+        }
+        return  arrayList;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ReverseFlowStrategy.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ReverseFlowStrategy.java
new file mode 100644
index 000000000..2ef051da1
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/flowbuilder/impl/ReverseFlowStrategy.java
@@ -0,0 +1,115 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.flowbuilder.impl;
+
+import java.util.*;
+
+import org.openecomp.appc.dg.flowbuilder.exception.InvalidDependencyModel;
+import org.openecomp.appc.domainmodel.Vnfc;
+
+
+public class ReverseFlowStrategy extends AbstractFlowStrategy {
+
+    @Override
+    protected List<List<Vnfc>> orderDependencies() {
+        ArrayList<List<Vnfc>> arrayList = new ArrayList<>();
+
+        Queue<Vnfc> queue1 = new LinkedList();
+        Set<Vnfc> queue2 = new LinkedHashSet<>();
+
+        Set<Vnfc> uniqueElementSet = new HashSet<>();
+        Set<Vnfc> duplicateElementSet = new HashSet<>();
+
+        // identifying independent nodes in queue1
+        for(int colIndex=0;colIndex<graph.getSize();colIndex++){
+            Integer sum = 0;
+            for(int rowIndex=0;rowIndex<graph.getSize();rowIndex++){
+                sum+= graph.getDependencyMatrix()[rowIndex][colIndex];
+            }
+            if(sum==0){
+                Vnfc vnfc = graph.getVertexList().get(colIndex);
+                queue1.add(vnfc);
+            }
+        }
+        if(queue1.isEmpty()){
+            throw new InvalidDependencyModel("There seems to be no leaf node for Vnfc dependencies");
+        }
+        arrayList.add((List<Vnfc>)queue1);
+        queue1 = new LinkedList<>(queue1);
+
+        boolean flag = true;
+
+        while(flag){
+            // iterating over queue1 and for each node in it finding all dependent nodes and putting them on queue2
+            while(!queue1.isEmpty()){
+                Vnfc listItem = queue1.remove();
+                Integer rowIndex = graph.getIndex(listItem);
+                for(Integer index =0;index<graph.getSize();index++){
+                    Integer value = graph.getDependencyMatrix()[rowIndex][index];
+                    if(value ==1){
+                        Vnfc vnfc = graph.getVertexList().get(index);
+                        queue2.add(vnfc);
+                    }
+                }
+            }
+            for(Vnfc vnfc:queue2){
+                if(!uniqueElementSet.add(vnfc)){
+                    duplicateElementSet.add(vnfc);
+                }
+            }
+            if(queue2.isEmpty()){
+                flag= false; // empty queue2 indicates that all leaf nodes have been identified, i.e. stop the iteration
+            }
+            else{
+                arrayList.add(new ArrayList<Vnfc>(queue2));
+                if(arrayList.size()>graph.getSize()){
+                    // dependency list cannot be larger than total number of nodes
+                    // if it happens indicates cycle in the dependency
+                    throw new InvalidDependencyModel("Cycle detected in the VNFC dependencies");
+                }
+                queue1.addAll(queue2);
+                queue2 = new LinkedHashSet<>();
+            }
+        }
+        // If any node depends on multiple nodes present in different execution sequence,
+        // its execution should happen on the higher order, removing its presence on lower execution sequence
+        if(!duplicateElementSet.isEmpty()){
+            for(Vnfc vnfc:duplicateElementSet){
+                boolean firstOccurrence= true;
+                for(int i=0;i<arrayList.size();i++){
+                    List<Vnfc> list = arrayList.get(i);
+                    if(list.contains(vnfc)){
+                        if(firstOccurrence){
+                            firstOccurrence =false;
+                            list.remove(vnfc);
+                        }
+                        else{
+                            continue;
+                        }
+                    }
+
+                }
+            }
+        }
+        return  arrayList;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/DependencyTypes.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/DependencyTypes.java
new file mode 100644
index 000000000..e8b8c2591
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/DependencyTypes.java
@@ -0,0 +1,36 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+
+public enum DependencyTypes {
+    RESOURCE;
+
+    public static DependencyTypes findByString(String dependencyTypeStr){
+        for(DependencyTypes dependencyType : DependencyTypes.values()){
+            if(dependencyType.name().equalsIgnoreCase(dependencyTypeStr)){
+                return dependencyType;
+            }
+        }
+        return null;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/FlowStrategies.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/FlowStrategies.java
new file mode 100644
index 000000000..8c3126bb5
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/FlowStrategies.java
@@ -0,0 +1,36 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+
+public enum FlowStrategies {
+    FORWARD,REVERSE;
+
+    public static FlowStrategies findByString(String flowStrategyStr){
+        for(FlowStrategies flowStrategy:FlowStrategies.values()){
+            if(flowStrategy.name().equalsIgnoreCase(flowStrategyStr)){
+                return flowStrategy;
+            }
+        }
+        return null;
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/InventoryModel.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/InventoryModel.java
new file mode 100644
index 000000000..ffd3a35ba
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/InventoryModel.java
@@ -0,0 +1,43 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+import org.openecomp.appc.domainmodel.Vnf;
+
+
+public class InventoryModel {
+
+    private Vnf vnf;
+
+    public InventoryModel(Vnf vnf){
+        this.vnf= vnf;
+    }
+
+    public Vnf getVnf() {
+        return vnf;
+    }
+
+    @Override
+    public String toString() {
+        return "InventoryModel = " + vnf.toString();
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/Node.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/Node.java
new file mode 100644
index 000000000..a751504b8
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/Node.java
@@ -0,0 +1,74 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+import java.util.LinkedList;
+import java.util.List;
+
+
+public class Node<T> {
+    T child;
+    List<T> parents;
+
+    @Override
+    public int hashCode(){
+        return child.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object object){
+        if(object == null){
+            return false;
+        }
+        if(!(object instanceof Node)){
+            return false;
+        }
+        Node node = (Node)object;
+        return this.child.equals(node.getChild());
+    }
+
+    public Node(T child){
+        this.child = child;
+        this.parents = new LinkedList<>();
+    }
+
+    public T getChild() {
+        return child;
+    }
+
+    public List<T> getParents() {
+        return parents;
+    }
+
+    public void addParent(T parent){
+        this.parents.add(parent);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder("Node : child = " + child + " , parents = ");
+        for(T parent:parents){
+            stringBuilder.append(parent).append(",");
+        }
+        return stringBuilder.toString();
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcDependencyModel.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcDependencyModel.java
new file mode 100644
index 000000000..12b5c15a5
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcDependencyModel.java
@@ -0,0 +1,48 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+import java.util.Set;
+
+import org.openecomp.appc.domainmodel.Vnfc;
+
+
+public class VnfcDependencyModel {
+    private Set<Node<Vnfc>> dependencies;
+
+    public VnfcDependencyModel(Set<Node<Vnfc>> dependencies){
+        this.dependencies = dependencies;
+    }
+
+    public Set<Node<Vnfc>> getDependencies() {
+        return dependencies;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder("dependencies = ");
+        for(Node node:dependencies){
+            stringBuilder.append(node.toString()).append(", ");
+        }
+        return super.toString();
+    }
+}
diff --git a/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcFlowModel.java b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcFlowModel.java
new file mode 100644
index 000000000..ef3934162
--- /dev/null
+++ b/appc-dg/appc-dg-shared/appc-dg-dependency-model/src/main/java/org/openecomp/appc/dg/objects/VnfcFlowModel.java
@@ -0,0 +1,89 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * openECOMP : APP-C
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights
+ * 						reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.appc.dg.objects;
+
+import java.util.*;
+
+import org.openecomp.appc.domainmodel.Vnfc;
+
+
+public class VnfcFlowModel {
+    private Map<Integer,List<Vnfc>> flowModelMap;
+
+    private VnfcFlowModel(VnfcFlowModelBuilder builder){
+        this.flowModelMap = builder.map;
+
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder("Flow Model : ");
+        Iterator<List<Vnfc>> iterator = getModelIterator();
+        while(iterator.hasNext()){
+            for(Vnfc vnfc:iterator.next()){
+                stringBuilder.append(vnfc.toString()).append(", \n");
+            }
+        }
+
+        return stringBuilder.toString();
+    }
+
+    public Iterator<List<Vnfc>> getModelIterator(){
+        return flowModelMap.values().iterator();
+    }
+
+    public static class VnfcFlowModelBuilder{
+
+        Map<Integer,List<Vnfc>> map;
+
+        public VnfcFlowModelBuilder(){
+            map = new HashMap<>();
+        }
+
+        public VnfcFlowModelBuilder addMetadata(Integer index,Vnfc vnfc){
+            List<Vnfc> vnfcList = this.map.get(index);
+            if(vnfcList == null){
+                vnfcList = new LinkedList<>();
+                map.put(index,vnfcList);
+            }
+            vnfcList.add(vnfc);
+            return this;
+        }
+
+        public VnfcFlowModelBuilder addMetadata(Integer index,List<Vnfc> vnfcs){
+            List<Vnfc> vnfcList = this.map.get(index);
+            if(vnfcList == null){
+                vnfcList = new LinkedList<>();
+                map.put(index,vnfcList);
+            }
+            vnfcList.addAll(vnfcs);
+            return this;
+        }
+
+        public VnfcFlowModel build(){
+            return new VnfcFlowModel(this);
+        }
+
+    }
+
+
+}