DocumentRelationBuilderHasTypeArrayKey

Author: omarlarus

neo4j-json/src/main/java/org/neo4j/helpers/json/document/impl/DocumentRelationBuilderHasTypeArrayKey.java

@@ -0,0 +1,174 @@
+/**
+ * Copyright (c) 2016 LARUS Business Automation [http://www.larus-ba.it]
+ * <p>
+ * This file is part of the "LARUS Integration Framework for Neo4j".
+ * <p>
+ * The "LARUS Integration Framework for Neo4j" is 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.neo4j.helpers.json.document.impl;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import org.apache.commons.lang3.ArrayUtils;
+import org.neo4j.graphdb.Direction;
+import org.neo4j.graphdb.GraphDatabaseService;
+import org.neo4j.graphdb.Node;
+import org.neo4j.graphdb.Relationship;
+import org.neo4j.graphdb.RelationshipType;
+import org.neo4j.graphdb.Result;
+import org.neo4j.helpers.json.document.DocumentRelationBuilder;
+import org.neo4j.helpers.json.document.context.DocumentRelationContext;
+import org.neo4j.logging.Log;
+
+/**
+ * Build relationship with name "HAS_"+the type of destination node
+ * ES: HAS_TRACKS
+ * @author Omar Rampado
+ * FIXME merge code with DocumentRelationBuilderTypeArrayKey
+ */
+public class DocumentRelationBuilderHasTypeArrayKey implements DocumentRelationBuilder {
+	
+	private static final String DOC_KEYS = "docKeys";
+	
+	private GraphDatabaseService db;
+	
+	private Log log;
+	
+	/**
+	 * @param db the db to set
+	 */
+	public void setDb(GraphDatabaseService db) {
+		this.db = db;
+	}
+	
+	/**
+	 * @param log the log to set
+	 */
+	public void setLog(Log log) {
+		this.log = log;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.neo4j.helpers.json.document.DocumentRelationBuilder#buildRelation(org.neo4j.graphdb.Node, org.neo4j.graphdb.Node, org.neo4j.helpers.json.document.DocumentRelationContext)
+	 */
+	@Override
+	public Relationship buildRelation(Node parent, Node child, DocumentRelationContext context) {
+		String childType = (String) child.getProperty("type");
+		String relationName = "HAS_"+childType.toUpperCase();
+		
+		RelationshipType type = RelationshipType.withName( relationName );
+		
+		//check if already exists
+		Iterable<Relationship> relationships = child.getRelationships(Direction.INCOMING,type);
+		
+		Relationship relationship;
+
+		//find only relation between parent and child node
+		List<Relationship> rels = StreamSupport.stream(relationships.spliterator(), false)
+				.filter(rel -> rel.getStartNode().getId() == parent.getId())
+				.collect(Collectors.toList());
+
+		if(rels.isEmpty())
+		{
+			relationship = parent.createRelationshipTo(child, type);
+			if(log.isDebugEnabled())
+				log.debug("Create new Relation "+relationship);
+		}else
+		{
+			relationship = rels.get(0);
+			if(log.isDebugEnabled())
+				log.debug("Update Relation "+relationship);
+		}
+
+		//manage array of keys
+		
+		String[] keys = new String[0];
+		
+		//create property if doesn't exists (new relation)
+		if(relationship.getAllProperties().containsKey(DOC_KEYS))
+		{
+			keys = (String[]) relationship.getProperty(DOC_KEYS);
+		}
+		
+		//set document key into property
+		String documentKey = context.getDocumentKey();
+		if(! ArrayUtils.contains(keys, documentKey))
+		{
+			keys = ArrayUtils.add(keys, documentKey);			
+			relationship.setProperty(DOC_KEYS, keys);
+		}
+		
+		
+		return relationship;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.neo4j.helpers.json.document.DocumentRelationBuilder#deleteRelations(org.neo4j.helpers.json.document.DocumentRelationContext)
+	 */
+	@Override
+	public Set<Node> deleteRelations(DocumentRelationContext context) {
+		Set<Node> orphans = new HashSet<>();
+		
+		Result result = db.execute("MATCH (p)-[r]->(c) WHERE \""+context.getDocumentKey()+"\" IN r."+DOC_KEYS+" RETURN r");
+		result.forEachRemaining((res)->{
+			Relationship rel = (Relationship) res.get("r");
+			String[] keys = (String[]) rel.getProperty(DOC_KEYS);
+			if(keys.length == 1)
+			{
+				Node parent = rel.getStartNode();
+				Node child = rel.getEndNode();
+				rel.delete();
+				if(log.isDebugEnabled())
+				{
+					log.debug("Delete relation "+rel);
+				}
+				
+				updateOrphans(orphans, parent);
+				updateOrphans(orphans, child);
+				
+			}else
+			{
+				//if other document pass through this relationship
+				keys = ArrayUtils.removeElement(keys, context.getDocumentKey());
+				rel.setProperty(DOC_KEYS, keys);
+			}
+		});
+		
+		return orphans;
+	}
+	
+	/**
+	 * Update orphans collection with node 
+	 * @param orphans
+	 * @param node
+	 * @return true if node is orphan
+	 */
+	private boolean updateOrphans(Set<Node> orphans, Node node)
+	{
+		boolean orphan = ! node.getRelationships().iterator().hasNext();
+		
+		if(orphan)
+		{
+			orphans.add(node);
+		}
+		
+		return orphan;
+	}
+
+}