org.neo4j.helpers.json.document.impl.DocumentRelationBuilderByKey.java Source code

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Here is the source code for org.neo4j.helpers.json.document.impl.DocumentRelationBuilderByKey.java

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/**
 * Copyright (c) 2017 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.StringUtils;
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 using document key as label
 * @author Omar Rampado
 *
 */
public class DocumentRelationBuilderByKey implements DocumentRelationBuilder {

    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 documentKey = context.getDocumentKey();
        if (StringUtils.isBlank(documentKey)) {
            return null;
        }

        RelationshipType relationType = RelationshipType.withName(documentKey);

        //check if already exists
        Iterable<Relationship> relationships = child.getRelationships(Direction.INCOMING, relationType);

        //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());

        Relationship relationship;

        if (rels.isEmpty()) {
            relationship = parent.createRelationshipTo(child, relationType);
            if (log.isDebugEnabled())
                log.debug("Create new Relation " + relationship);
        } else {
            relationship = rels.get(0);
            if (log.isDebugEnabled())
                log.debug("Update Relation " + relationship);
        }

        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<>();

        String documentKey = context.getDocumentKey();
        if (StringUtils.isBlank(documentKey)) {
            return orphans;
        }

        Result result = db.execute("MATCH (p)-[r:" + documentKey + "]->(c) RETURN r");
        result.forEachRemaining((res) -> {
            Relationship rel = (Relationship) res.get("r");
            Node parent = rel.getStartNode();
            Node child = rel.getEndNode();
            rel.delete();
            if (log.isDebugEnabled()) {
                log.debug("Delete relation " + rel);
            }
            updateOrphans(orphans, parent);
            updateOrphans(orphans, child);
        });

        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;
    }
}