001/*
002 * Copyright 2012-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.batch.item.data;
018
019import java.util.List;
020
021import org.apache.commons.logging.Log;
022import org.apache.commons.logging.LogFactory;
023import org.neo4j.ogm.session.Session;
024import org.neo4j.ogm.session.SessionFactory;
025
026import org.springframework.batch.item.ItemWriter;
027import org.springframework.beans.factory.InitializingBean;
028import org.springframework.util.Assert;
029import org.springframework.util.CollectionUtils;
030
031/**
032 * <p>
033 * A {@link ItemWriter} implementation that writes to a Neo4j database.
034 * </p>
035 *
036 * <p>
037 * This writer is thread-safe once all properties are set (normal singleton
038 * behavior) so it can be used in multiple concurrent transactions.
039 * </p>
040 *
041 * @author Michael Minella
042 * @author Glenn Renfro
043 * @author Mahmoud Ben Hassine
044 *
045 */
046public class Neo4jItemWriter<T> implements ItemWriter<T>, InitializingBean {
047
048        protected static final Log logger = LogFactory
049                        .getLog(Neo4jItemWriter.class);
050
051        private boolean delete = false;
052
053        private SessionFactory sessionFactory;
054
055        /**
056         * Boolean flag indicating whether the writer should save or delete the item at write
057         * time.
058         * @param delete true if write should delete item, false if item should be saved.
059         * Default is false.
060         */
061        public void setDelete(boolean delete) {
062                this.delete = delete;
063        }
064
065        /**
066         * Establish the session factory that will be used to create {@link Session} instances
067         * for interacting with Neo4j.
068         * @param sessionFactory sessionFactory to be used.
069         */
070        public void setSessionFactory(SessionFactory sessionFactory) {
071                this.sessionFactory = sessionFactory;
072        }
073
074        /**
075         * Checks mandatory properties
076         *
077         * @see InitializingBean#afterPropertiesSet()
078         */
079        @Override
080        public void afterPropertiesSet() throws Exception {
081                Assert.state(this.sessionFactory != null,
082                                "A SessionFactory is required");
083        }
084
085        /**
086         * Write all items to the data store.
087         *
088         * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
089         */
090        @Override
091        public void write(List<? extends T> items) throws Exception {
092                if(!CollectionUtils.isEmpty(items)) {
093                        doWrite(items);
094                }
095        }
096
097        /**
098         * Performs the actual write using the template.  This can be overridden by
099         * a subclass if necessary.
100         *
101         * @param items the list of items to be persisted.
102         */
103        protected void doWrite(List<? extends T> items) {
104                if(delete) {
105                        delete(items);
106                }
107                else {
108                        save(items);
109                }
110        }
111
112        private void delete(List<? extends T> items) {
113                Session session = this.sessionFactory.openSession();
114
115                for(T item : items) {
116                        session.delete(item);
117                }
118        }
119
120        private void save(List<? extends T> items) {
121                Session session = this.sessionFactory.openSession();
122
123                for (T item : items) {
124                        session.save(item);
125                }
126        }
127}