Spring Batch: Processing Data From Web Service to MongoDB

Overview

In this post, we will look on how to create a Spring Batch application that consumes web service data and insert it in the MongoDB database.

Requirements

Developers who are reading this article must be familiarized with Spring Batch (Example) and MongoDB.

Environments

• Mongo database is deployed in MLab. Please follow the step in this Quick-Start.

• Batch application is deployed in Heroku PaaS. For details, look here.

• IDE STS or IntelliJ or Eclipse.

• Java 8 JDK.

NB: Batch can be run locally as well.

Scenario

The global scenario steps are:

1. Read data from web service, in this case: https://sunrise-sunset.org/api

Get coordinates of a list of cities, then call the API to read sunrise and sunset date time.

2. Process data and extract business data

Business processing of collected data

3. Insert processed data in MongoDB

Save processed data as mongo documents

Coding

• Input: List of cities data in JSON format in a local file as below:

[  
   {  
      "name":"Danemark",
      "cities":[  
         {  
            "name":"Copenhague",
            "lat":55.676098,
            "lng":12.568337,
            "timeZone":"CET"
         },
         {  
            "name":"Aarhus",
            "lat":56.162939,
            "lng":10.203921,
            "timeZone":"CET"
         },
         {  
            "name":"Odense",
            "lat":55.39594,
            "lng":10.38831,
            "timeZone":"CET"
         },
         {  
            "name":"Aalborg",
            "lat":57.046707,
            "lng":9.935932,
            "timeZone":"CET"
         }
      ]
   }
]

Our scenario takes input data from local json file. Mapping beans are as below:

Country bean:

import java.io.Serializable;
import java.util.List;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class BCountry implements Serializable{

private static final long serialVersionUID = 1L;

private String name;

private List<BCity> cities;

public BCountry() {
super();
}

public BCountry(String name, List<BCity> cities) {
super();
this.name = name;
this.cities = cities;
}

public BCountry(String name) {
super();
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public List<BCity> getCities() {
return cities;
}

public void setCities(List<BCity> cities) {
this.cities = cities;
}



@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((cities == null) ? 0 : cities.hashCode());
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
BCountry other = (BCountry) obj;
if (cities == null) {
if (other.cities != null)
return false;
} else if (!cities.equals(other.cities))
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}

@Override
public String toString() {
return "BCountry [name=" + name + ", cities=" + cities + "]";
}


}

and City Bean:

import java.io.Serializable;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class BCity implements Serializable {

private static final long serialVersionUID = 1L;

private String name, timeZone;
private double lat, lng;

public BCity() {
super();
}

public BCity(String name, String timeZone, double lat, double lng) {
super();
this.name = name;
this.timeZone = timeZone;
this.lat = lat;
this.lng = lng;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getTimeZone() {
return timeZone;
}

public void setTimeZone(String timeZone) {
this.timeZone = timeZone;
}

public double getLat() {
return lat;
}

public void setLat(double lat) {
this.lat = lat;
}

public double getLng() {
return lng;
}
public void setLng(double lng) {
this.lng = lng;
}

@Override
public String toString() {
return "BCity [name=" + name + ", timeZone=" + timeZone + ", lat=" + lat + ", lng=" + lng + "]";
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
long temp;
temp = Double.doubleToLongBits(lat);
result = prime * result + (int) (temp ^ (temp >>> 32));
temp = Double.doubleToLongBits(lng);
result = prime * result + (int) (temp ^ (temp >>> 32));
result = prime * result + ((name == null) ? 0 : name.hashCode());
result = prime * result + ((timeZone == null) ? 0 : timeZone.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
BCity other = (BCity) obj;
if (Double.doubleToLongBits(lat) != Double.doubleToLongBits(other.lat))
return false;
if (Double.doubleToLongBits(lng) != Double.doubleToLongBits(other.lng))
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
if (timeZone == null) {
if (other.timeZone != null)
return false;
} else if (!timeZone.equals(other.timeZone))
return false;
return true;
}

}

Batch reader implement @LineMapper. You can adapt the reader to our data sources (Example):

import java.util.List;

import org.springframework.batch.item.file.LineMapper;

import com.ahajri.batch.beans.BCountry;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;

public class BCountryJsonLineMapper implements LineMapper<List<BCountry>> {

private final ObjectMapper mapper = new ObjectMapper();

@Override
public List<BCountry> mapLine(String line, int lineNumber) throws Exception {
CollectionType collectionType =mapper.getTypeFactory().constructCollectionType(List.class, BCountry.class);
return mapper.readValue(line, collectionType);
}

}

When processing data Batch, check if business processed data for a given city on the same day is already saved in the database. Generic way for searching data in MongoDB is detailed in this post.

ItemProcessor transform @BCountry object to MongoDB Document objects. The process is detailed below:

public class BCountryPrayTimeEventItemProcessor implements ItemProcessor<List<BCountry>, List<Document>> {

private static final String EVENTS_COLLECTION_NAME = "event";

private static final Logger LOG = LoggerFactory.getLogger(BCountryPrayTimeEventItemProcessor.class);

@Autowired
private PrayTimeService prayTimeService;

@Autowired
private CloudMongoService cloudMongoService;

@Override
public List<Document> process(List<BCountry> items) throws Exception {
final List<Document> docs = new ArrayList<>();


items.stream().forEach(item -> {

final String countryName = item.getName();

item.getCities().stream().forEach(c -> {
final Document prayTimeCityEventDoc = new Document();
// loop cities and extract pray time for today
final String cityName = c.getName();
final String cityTimeZone = c.getTimeZone();
final double lat = c.getLat();
final double lng = c.getLng();

final LocalDateTime nowOfCity = LocalDateTime.now(ZoneId.of(cityTimeZone));


final QueryParam[] queryParams = new QueryParam[5];

queryParams[0] = new QueryParam("city_name", OperatorEnum.EQ.name(), cityName);
queryParams[1] = new QueryParam("event_type", OperatorEnum.EQ.name(), EventType.PRAY_TIME.name());
queryParams[2] = new QueryParam("month", OperatorEnum.EQ.name(), nowOfCity.getMonthValue());
queryParams[3] = new QueryParam("day_of_month", OperatorEnum.EQ.name(), nowOfCity.getDayOfMonth());
queryParams[4] = new QueryParam("country_name", OperatorEnum.EQ.name(), countryName);
List<Document> foundEvents = null;
try {
foundEvents = cloudMongoService.search(EVENTS_COLLECTION_NAME, queryParams);
} catch (BusinessException e1) {
LOG.error("====>No pray time found for city " + cityName + " on " + nowOfCity.getDayOfMonth() + "/"
+ nowOfCity.getMonthValue());
}

try {
if (CollectionUtils.isEmpty(foundEvents)) {
// Pray time not created yet
prayTimeCityEventDoc.put("country_name", countryName);
prayTimeCityEventDoc.put("city_name", cityName);
prayTimeCityEventDoc.put("event_type", EventType.PRAY_TIME.name());
prayTimeCityEventDoc.put("recurring", RecurringEnum.YEARLY.name());
prayTimeCityEventDoc.put("month", nowOfCity.getMonthValue());
prayTimeCityEventDoc.put("day_of_month", nowOfCity.getDayOfMonth());
prayTimeCityEventDoc.put("lat", lat);
prayTimeCityEventDoc.put("lng", lng);
prayTimeCityEventDoc.put("creation_date", HCDateUtils.convertToDateViaSqlTimestamp(nowOfCity));

final Map<String, Object> prayInfos = prayTimeService.getPrayTimeByLatLngDate(lat, lng,
Date.from(nowOfCity.atZone(ZoneId.of(cityTimeZone)).toInstant()), cityTimeZone);

prayTimeCityEventDoc.put("pray_infos", Document.parse(new Gson().toJson(prayInfos)));

docs.add(prayTimeCityEventDoc);

} else {
LOG.info(String.format("====>Pray time already exists for city: %s, month: %d, day:  %d",
cityName, nowOfCity.getMonthValue(), nowOfCity.getDayOfMonth()));
}
} catch (BusinessException e) {
LOG.error("Problem while calculating pray time: ", e);
throw new RuntimeException(e);
}
});
});
return docs;
}

}

Batch Configuration class:

@Configuration
@EnableBatchProcessing
@EnableScheduling
public class BatchConfiguration {

private static final String SCANDINAVIAN_COUNTRIES_JSON_FILE = "scandinavian-countries.json";
private static final String EVENT_COLLECTION_NAME = "event_collection";

private static final Logger LOG = LoggerFactory.getLogger(BatchConfiguration.class);

@Autowired
private JobBuilderFactory jobBuilderFactory;

@Autowired
private StepBuilderFactory stepBuilderFactory;

@Autowired
private MLabMongoService mlabMongoService;

@Bean
public ResourcelessTransactionManager transactionManager() {
return new ResourcelessTransactionManager();
}

@Bean
public MapJobRepositoryFactoryBean mapJobRepositoryFactory(ResourcelessTransactionManager txManager)
throws Exception {
MapJobRepositoryFactoryBean factory = new MapJobRepositoryFactoryBean(txManager);
factory.afterPropertiesSet();
return factory;
}

@Bean
public JobRepository jobRepository(MapJobRepositoryFactoryBean factory) throws Exception {
return (JobRepository) factory.getObject();
}

private SimpleJobLauncher jobLauncher;

@Bean
public SimpleJobLauncher jobLauncher(JobRepository jobRepository) {
jobLauncher.setJobRepository(jobRepository);
return jobLauncher;
}

@PostConstruct
private void initJobLauncher() {
jobLauncher = new SimpleJobLauncher();
}

@Bean
FlatFileItemReader<List<BCountry>> reader() {
FlatFileItemReader<List<BCountry>> reader = new FlatFileItemReader<>();
reader.setName("scandinaviandCountriesReader");
reader.setResource(new ClassPathResource(SCANDINAVIAN_COUNTRIES_JSON_FILE));
reader.setLineMapper(new BCountryJsonLineMapper());
return reader;
}

@Bean
public ItemWriter<List<Document>> writer() {
return new ItemWriter<List<Document>>() {
@Override
public void write(List<? extends List<Document>> items) throws Exception {
try {
if (!CollectionUtils.isEmpty(items) && items.size() > 0) {
List<Document> flatDocs = items.stream().flatMap(List::stream).collect(Collectors.toList());
mlabMongoService.insertMany(EVENT_COLLECTION_NAME, flatDocs);
} else {
LOG.warn("No event to save ....");
}
} catch (BusinessException e) {
throw new RuntimeException(e);
}
}
};
}

@Bean
public BCountryTimeEventItemProcessor processor() {
return new BCountryTimeEventItemProcessor();
}

@Bean
public Job scandvTimeJob() {
return jobBuilderFactory.get("scandvTimeJob").incrementer(new RunIdIncrementer()).flow(step1()).end()
.build();
}

@Bean
public Step step1() {
return stepBuilderFactory.get("step1").<List<BCountry>, List<Document>>chunk(10).reader(reader())
.processor(processor()).writer(writer()).build();
}
// end::jobstep[]

  //run at midnight 15 minutes every day
@Scheduled(cron = "0 15 0 * * *")
public void startScandvEventTimeJob() throws Exception {
LOG.info(" ====> Job Started at :" + new Date());
JobParameters param = new JobParametersBuilder().addString("JobID", String.valueOf(System.currentTimeMillis()))
.toJobParameters();
JobExecution execution = jobLauncher.run(scandvPrayTimeJob(), param);
LOG.info(" ====> Job finished with status :" + execution.getStatus());
}
}

Deploy de Batch to Heroku:

git add .
git commit -m "Deploy Batch"
git push heroku master

NB: to disable default Batch launching add this to application.yml

spring:
  batch:
    job:
      enabled: false

You can find the whole source code here : 

GitHub