1 files changed, 115 insertions, 0 deletions
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;
+    }
+}