fixes #600 - add a configuration option to mergeNodes that allows to …

…combine relationships of the same type and direction (#850)

docs/overview.adoc

@@ -654,11 +654,18 @@ CALL apoc.periodic.rock_n_roll('match (p:Person) return id(p) as id_p', 'MATCH (
 | call apoc.refactor.categorize(node, propertyKey, type, outgoing, label) | turn each unique propertyKey into a category node and connect to it
 |===
 
-On mergeRelationship with config properties you can choose from 3 different management:
+On mergeRelationship and mergeNodes with config properties you can choose from 3 different management:
  * "overwrite" : if there is the same property in more relationship, in the new one will have the last relationship's property value
  * "discard" : if there is the same property in more relationship, the new one will have the first relationship's property value
  * "combine" : if there is the same property in more relationship, the new one a value's array with all relationships' values
 
+On mergeNodes procedure there is also a config parameter to merge relationships of the merged nodes:
+ * "mergeRels: true/false" : give the possibility to merge relationships with same type and direction.
+
+If relationships have same start and end nodes will be merged into one, and properties managed by the properties config.
+If relationships have different start/end nodes (related to direction), relationships will be maintained and properties will be combine in all relationship.
+
+
 TODO:
 
 * merge nodes by label + property

docs/refactor.adoc

@@ -28,6 +28,94 @@ This config option also works for `apoc.refactor.mergeRelationships([rels],{conf
 | combine | if there is only one property in list, it will be set / kept as single property otherwise create an array, tries to coerce values
 |===
 
+For mergeNodes you can Merge relationships with same type and direction, you can spacify this with property mergeRels.
+Relationships properties are combined.
+
+.example1 - Relationships with same start and end nodes
+
+First of all we have to create nodes and relationships
+
+---
+Create (n1:Person {name:'Tom'}),
+(n2:Person {name:'John'}),
+(n3:Company {name:'Company1'}),
+(n5:Car {brand:'Ferrari'}),
+(n6:Animal:Cat {name:'Derby'}),
+(n7:City {name:'London'}),
+(n1)-[:WORKS_FOR{since:2015}]->(n3),
+(n2)-[:WORKS_FOR{since:2018}]->(n3),
+(n3)-[:HAS_HQ{since:2004}]->(n7),
+(n1)-[:DRIVE{since:2017}]->(n5),
+(n2)-[:HAS{since:2013}]->(n6)
+return *;
+---
+
+image::{img}/apoc.refactor.mergeNodes.createDataSetFirstExample.png[]
+
+Next step is calling the apoc to merge nodes :Person
+
+---
+MATCH (a1:Person{name:'John'}), (a2:Person {name:'Tom'})
+WITH head(collect([a1,a2])) as nodes
+CALL apoc.refactor.mergeNodes(nodes,{properties:"combine", mergeRels:true}) yield node
+MATCH (n)-[r:WORKS_FOR]->(c) return *
+---
+
+and the result is:
+
+image::{img}/apoc.refactor.mergeNodes.resultFirstExample.png[]
+
+In this case we have relationships with same start and end nodes so relationships are merged into one and properties are combined.
+
+
+.example2 - Relationships with different start or end nodes
+
+---
+Create (n1:Person {name:'Tom'}),
+(n2:Person {name:'John'}),
+(n3:Company {name:'Company1'}),
+(n4:Company {name:'Company2'}),
+(n5:Car {brand:'Ferrari'}),
+(n6:Animal:Cat {name:'Derby'}),
+(n7:City {name:'London'}),
+(n8:City {name:'Liverpool'}),
+(n1)-[:WORKS_FOR{since:2015}]->(n3),
+(n2)-[:WORKS_FOR{since:2018}]->(n4),
+(n3)-[:HAS_HQ{since:2004}]->(n7),
+(n4)-[:HAS_HQ{since:2007}]->(n8),
+(n1)-[:DRIVE{since:2017}]->(n5),
+(n2)-[:HAS{since:2013}]->(n6)
+return *;
+---
+
+image::{img}/apoc.refactor.mergeNodes.createDataSetSecondExample.png[]
+
+Next step is calling the apoc to merge nodes :Person
+
+---
+MATCH (a1:Person{name:'John'}), (a2:Person {name:'Tom'})
+WITH head(collect([a1,a2])) as nodes
+CALL apoc.refactor.mergeNodes(nodes,{properties:"combine", mergeRels:true}) yield node
+MATCH (n)-[r:WORKS_FOR]->(c) return n.name,r.since,c.name;
+---
+
+and the result is:
+
+image::{img}/apoc.refactor.mergeNodes.resultSecondExample.png[]
+
+image::{img}/apoc.refactor.mergeNodes.resultSecondExampleData.png[]
+
+In this case we have relationships with different end nodes so all relationships are maintained and properties are combined into all relationships.
+
+
+---
+MATCH (p:Person)
+WITH p ORDER BY p.created DESC // newest one first
+WITH p.email, collect(p) as nodes
+CALL apoc.refactor.mergeNodes(nodes, {properties:'combine', mergeRels: true}) YIELD node
+RETURN node
+---
+
 
 == Normalize boolean properties
 

src/main/java/apoc/refactor/GraphRefactoring.java

@@ -31,12 +31,12 @@ private Stream<NodeRefactorResult> doCloneNodes(@Name("nodes") List<Node> nodes,
                 Node newNode = copyLabels(node, db.createNode());
 
                 Map<String, Object> properties = node.getAllProperties();
-                if (skipProperties!=null && !skipProperties.isEmpty())
+                if (skipProperties != null && !skipProperties.isEmpty())
                     for (String skip : skipProperties) properties.remove(skip);
 
                 Node copy = copyProperties(properties, newNode);
                 if (withRelationships) {
-                    copyRelationships(node, copy,false);
+                    copyRelationships(node, copy, false);
                 }
                 return result.withOther(copy);
             } catch (Exception e) {
@@ -52,8 +52,8 @@ public Stream<NodeRefactorResult> extractNode(@Name("relationships") Object rels
             NodeRefactorResult result = new NodeRefactorResult(rel.getId());
             try {
                 Node copy = copyProperties(rel, db.createNode(Util.labels(labels)));
-                copy.createRelationshipTo(rel.getEndNode(),RelationshipType.withName(outType));
-                rel.getStartNode().createRelationshipTo(copy,RelationshipType.withName(inType));
+                copy.createRelationshipTo(rel.getEndNode(), RelationshipType.withName(outType));
+                rel.getStartNode().createRelationshipTo(copy, RelationshipType.withName(inType));
                 rel.delete();
                 return result.withOther(copy);
             } catch (Exception e) {
@@ -70,7 +70,7 @@ public Stream<RelationshipRefactorResult> collapseNode(@Name("nodes") Object nod
             try {
                 Iterable<Relationship> outRels = node.getRelationships(Direction.OUTGOING);
                 Iterable<Relationship> inRels = node.getRelationships(Direction.INCOMING);
-                if (node.getDegree(Direction.OUTGOING) == 1 &&  node.getDegree(Direction.INCOMING) == 1) {
+                if (node.getDegree(Direction.OUTGOING) == 1 && node.getDegree(Direction.INCOMING) == 1) {
                     Relationship outRel = outRels.iterator().next();
                     Relationship inRel = inRels.iterator().next();
                     Relationship newRel = inRel.getStartNode().createRelationshipTo(outRel.getEndNode(), RelationshipType.withName(type));
@@ -82,7 +82,7 @@ public Stream<RelationshipRefactorResult> collapseNode(@Name("nodes") Object nod
 
                     return result.withOther(newRel);
                 } else {
-                    return result.withError(String.format("Node %d has more that 1 outgoing %d or incoming %d relationships",node.getId(),node.getDegree(Direction.OUTGOING),node.getDegree(Direction.INCOMING)));
+                    return result.withError(String.format("Node %d has more that 1 outgoing %d or incoming %d relationships", node.getId(), node.getDegree(Direction.OUTGOING), node.getDegree(Direction.INCOMING)));
                 }
             } catch (Exception e) {
                 return result.withError(e);
@@ -96,9 +96,9 @@ public Stream<RelationshipRefactorResult> collapseNode(@Name("nodes") Object nod
     @Procedure(mode = Mode.WRITE)
     @Description("apoc.refactor.cloneNodes([node1,node2,...]) clone nodes with their labels and properties")
     public Stream<NodeRefactorResult> cloneNodes(@Name("nodes") List<Node> nodes,
-                                                 @Name(value = "withRelationships",defaultValue = "false") boolean withRelationships,
-                                                 @Name(value = "skipProperties",defaultValue = "[]") List<String> skipProperties) {
-        return doCloneNodes(nodes,withRelationships,skipProperties);
+                                                 @Name(value = "withRelationships", defaultValue = "false") boolean withRelationships,
+                                                 @Name(value = "skipProperties", defaultValue = "[]") List<String> skipProperties) {
+        return doCloneNodes(nodes, withRelationships, skipProperties);
     }
 
     /**
@@ -108,7 +108,7 @@ public Stream<NodeRefactorResult> cloneNodes(@Name("nodes") List<Node> nodes,
     @Deprecated
     @Description("apoc.refactor.cloneNodesWithRelationships([node1,node2,...]) clone nodes with their labels, properties and relationships")
     public Stream<NodeRefactorResult> cloneNodesWithRelationships(@Name("nodes") List<Node> nodes) {
-        return doCloneNodes(nodes,true, Collections.emptyList());
+        return doCloneNodes(nodes, true, Collections.emptyList());
     }
 
     /**
@@ -117,15 +117,17 @@ public Stream<NodeRefactorResult> cloneNodesWithRelationships(@Name("nodes") Lis
      */
     @Procedure(mode = Mode.WRITE)
     @Description("apoc.refactor.mergeNodes([node1,node2],[{properties:'override' or 'discard' or 'combine'}]) merge nodes onto first in list")
-    public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(value= "config", defaultValue = "") Map<String, Object> config) {
+    public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(value = "config", defaultValue = "") Map<String, Object> config) {
         if (nodes == null || nodes.isEmpty()) return Stream.empty();
+        RefactorConfig conf = new RefactorConfig(config);
         // grab write locks upfront consistently ordered
-        try (Transaction tx=db.beginTx()) {
-	        nodes.stream().distinct().sorted(Comparator.comparingLong(Node::getId)).forEach( tx::acquireWriteLock );
+        try (Transaction tx = db.beginTx()) {
+            nodes.stream().distinct().sorted(Comparator.comparingLong(Node::getId)).forEach(tx::acquireWriteLock);
             tx.success();
         }
-        RefactorConfig conf = new RefactorConfig(config);
+
         final Node first = nodes.get(0);
+
         nodes.stream().skip(1).distinct().forEach(node -> mergeNodes(node, first, true, conf));
         return Stream.of(new NodeResult(first));
     }
@@ -136,14 +138,14 @@ public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(valu
      */
     @Procedure(mode = Mode.WRITE)
     @Description("apoc.refactor.mergeRelationships([rel1,rel2]) merge relationships onto first in list")
-    public Stream<RelationshipResult> mergeRelationships(@Name("rels") List<Relationship> relationships, @Name(value= "config", defaultValue = "") Map<String, Object> config) {
+    public Stream<RelationshipResult> mergeRelationships(@Name("rels") List<Relationship> relationships, @Name(value = "config", defaultValue = "") Map<String, Object> config) {
         if (relationships == null || relationships.isEmpty()) return Stream.empty();
         RefactorConfig conf = new RefactorConfig(config);
         Iterator<Relationship> it = relationships.iterator();
         Relationship first = it.next();
         while (it.hasNext()) {
             Relationship other = it.next();
-            if(first.getStartNode().equals(other.getStartNode()) && first.getEndNode().equals(other.getEndNode()))
+            if (first.getStartNode().equals(other.getStartNode()) && first.getEndNode().equals(other.getEndNode()))
                 mergeRels(other, first, true, conf);
             else
                 throw new RuntimeException("All Relationships must have the same start and end nodes.");
@@ -180,7 +182,7 @@ public Stream<RelationshipRefactorResult> to(@Name("relationship") Relationship
         RelationshipRefactorResult result = new RelationshipRefactorResult(rel.getId());
         try {
             Relationship newRel = rel.getStartNode().createRelationshipTo(newNode, rel.getType());
-            copyProperties(rel,newRel);
+            copyProperties(rel, newRel);
             rel.delete();
             return Stream.of(result.withOther(newRel));
         } catch (Exception e) {
@@ -195,7 +197,7 @@ public Stream<RelationshipRefactorResult> invert(@Name("relationship") Relations
         RelationshipRefactorResult result = new RelationshipRefactorResult(rel.getId());
         try {
             Relationship newRel = rel.getEndNode().createRelationshipTo(rel.getStartNode(), rel.getType());
-            copyProperties(rel,newRel);
+            copyProperties(rel, newRel);
             rel.delete();
             return Stream.of(result.withOther(newRel));
         } catch (Exception e) {
@@ -213,7 +215,7 @@ public Stream<RelationshipRefactorResult> from(@Name("relationship") Relationshi
         RelationshipRefactorResult result = new RelationshipRefactorResult(rel.getId());
         try {
             Relationship newRel = newNode.createRelationshipTo(rel.getEndNode(), rel.getType());
-            copyProperties(rel,newRel);
+            copyProperties(rel, newRel);
             rel.delete();
             return Stream.of(result.withOther(newRel));
         } catch (Exception e) {
@@ -235,13 +237,13 @@ public void normalizeAsBoolean(
             PropertyContainer pc = (PropertyContainer) entity;
             Object value = pc.getProperty(propertyKey, null);
             if (value != null) {
-                boolean isTrue  = trueValues.contains(value);
+                boolean isTrue = trueValues.contains(value);
                 boolean isFalse = falseValues.contains(value);
                 if (isTrue && !isFalse) {
-                    pc.setProperty(propertyKey, true );
+                    pc.setProperty(propertyKey, true);
                 }
                 if (!isTrue && isFalse) {
-                    pc.setProperty(propertyKey, false );
+                    pc.setProperty(propertyKey, false);
                 }
                 if (!isTrue && !isFalse) {
                     pc.removeProperty(propertyKey);
@@ -276,19 +278,19 @@ public void categorize(
         // Create batches of nodes
         List<Node> batch = null;
         List<Future<Void>> futures = new ArrayList<>();
-        try(Transaction tx = db.beginTx()) {
+        try (Transaction tx = db.beginTx()) {
             for (Node node : db.getAllNodes()) {
                 if (batch == null) {
                     batch = new ArrayList<>((int) batchSize);
                 }
                 batch.add(node);
                 if (batch.size() == batchSize) {
-                    futures.add( categorizeNodes(batch, sourceKey, relationshipType, outgoing, label, targetKey, copiedKeys) );
+                    futures.add(categorizeNodes(batch, sourceKey, relationshipType, outgoing, label, targetKey, copiedKeys));
                     batch = null;
                 }
             }
             if (batch != null) {
-                futures.add( categorizeNodes(batch, sourceKey, relationshipType, outgoing, label, targetKey, copiedKeys) );
+                futures.add(categorizeNodes(batch, sourceKey, relationshipType, outgoing, label, targetKey, copiedKeys));
             }
 
             // Await processing of node batches
@@ -341,6 +343,12 @@ private Node mergeNodes(Node source, Node target, boolean delete, RefactorConfig
             copyRelationships(source, copyLabels(source, target), delete);
             if (delete) source.delete();
             PropertiesManager.mergeProperties(properties, target, conf);
+
+            if (conf.getMergeRelsAllowed()) {
+                Map<String, Object> map = Collections.singletonMap("properties", "combine");
+                mergeRelsWithSameTypeAndDirectionInMergeNodes(target, new RefactorConfig(map), Direction.OUTGOING);
+                mergeRelsWithSameTypeAndDirectionInMergeNodes(target, new RefactorConfig(map), Direction.INCOMING);
+            }
         } catch (NotFoundException e) {
             log.warn("skipping a node for merging: " + e.getCause().getMessage());
         }
@@ -365,17 +373,17 @@ private Node copyRelationships(Node source, Node target, boolean delete) {
     private Node copyLabels(Node source, Node target) {
         for (Label label : source.getLabels()) {
             if (!target.hasLabel(label)) {
-                    target.addLabel(label);
+                target.addLabel(label);
             }
         }
         return target;
     }
 
     private <T extends PropertyContainer> T copyProperties(PropertyContainer source, T target) {
-        return copyProperties(source.getAllProperties(),target);
+        return copyProperties(source.getAllProperties(), target);
     }
 
-    private <T extends PropertyContainer> T copyProperties(Map<String,Object> source, T target) {
+    private <T extends PropertyContainer> T copyProperties(Map<String, Object> source, T target) {
         for (Map.Entry<String, Object> prop : source.entrySet())
             target.setProperty(prop.getKey(), prop.getValue());
         return target;
@@ -396,4 +404,26 @@ private Relationship copyRelationship(Relationship rel, Node source, Node target
         Relationship newrel = startNode.createRelationshipTo(endNode, rel.getType());
         return copyProperties(rel, newrel);
     }
+
+
+    public void mergeRelsWithSameTypeAndDirectionInMergeNodes(Node node, RefactorConfig config, Direction dir) {
+
+        int i = 1;
+        for (Iterator<Relationship> it = node.getRelationships(dir).iterator(); it.hasNext(); ) {
+            Relationship relSource = it.next();
+            StreamSupport.stream(node.getRelationships(dir, relSource.getType()).spliterator(), false)
+                    .skip(i)
+                    .distinct()
+                    .forEach(relTarget -> {
+                        if (relSource.getStartNode().equals(relTarget.getStartNode()) && relSource.getEndNode().equals(relTarget.getEndNode()))
+                            mergeRels(relSource, relTarget, true, config);
+                        else {
+                            mergeRels(relSource, relTarget, false, config);
+                            mergeRels(relTarget, relSource, false, config);
+                        }
+                    });
+            i++;
+        }
+
+    }
 }

src/main/java/apoc/refactor/util/RefactorConfig.java

@@ -18,13 +18,17 @@ public class RefactorConfig {
 
 	private Map<String,String> propertiesManagement = Collections.singletonMap(MATCH_ALL, OVERWRITE);
 
+	private Object mergeRelsAllowed;
+
 	public RefactorConfig(Map<String,Object> config) {
 		Object value = config.get("properties");
 		if (value instanceof String) {
 			this.propertiesManagement = Collections.singletonMap(MATCH_ALL, value.toString());
 		} else if (value instanceof Map) {
 			this.propertiesManagement = (Map<String,String>)value;
 		}
+
+		this.mergeRelsAllowed = config.get("mergeRels");
 	}
 
 	public String getMergeMode(String name){
@@ -37,4 +41,8 @@ public String getMergeMode(String name){
 
 	}
 
+	public boolean getMergeRelsAllowed(){
+		return mergeRelsAllowed == null ? false : (boolean) mergeRelsAllowed;
+	}
+
 }