A Guide to the InfluxDBMapper and QueryBuilder for Java: Part 1

With the release of the latest InfluxDB-Java driver version came along the InfluxDBMapper.

To get started, we need to spin up an InfluxDB instance, and Docker is the easiest way to do so. We just follow the steps as described here.

Now we have a database with some data, and we are ready to execute our queries.

We have the measure h2o_feet:

> SELECT * FROM "h2o_feet"

name: h2o_feet
--------------
time                   level description      location       water_level
2015-08-18T00:00:00Z   below 3 feet           santa_monica   2.064
2015-08-18T00:00:00Z   between 6 and 9 feet   coyote_creek   8.12
[...]
2015-09-18T21:36:00Z   between 3 and 6 feet   santa_monica   5.066
2015-09-18T21:42:00Z   between 3 and 6 feet   santa_monica   4.938

Let's create a model for that.

package com.gkatzioura.mapper.showcase;

import java.time.Instant;
import java.util.concurrent.TimeUnit;

import org.influxdb.annotation.Column;
import org.influxdb.annotation.Measurement;

@Measurement(name = "h2o_feet", database = "NOAA_water_database", timeUnit = TimeUnit.SECONDS)
public class H2OFeetMeasurement {

    @Column(name = "time")
    private Instant time;

    @Column(name = "level description")
    private String levelDescription;

    @Column(name = "location")
    private String location;

    @Column(name = "water_level")
    private Double waterLevel;

    public Instant getTime() {
        return time;
    }

    public void setTime(Instant time) {
        this.time = time;
    }

    public String getLevelDescription() {
        return levelDescription;
    }

    public void setLevelDescription(String levelDescription) {
        this.levelDescription = levelDescription;
    }

    public String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public Double getWaterLevel() {
        return waterLevel;
    }

    public void setWaterLevel(Double waterLevel) {
        this.waterLevel = waterLevel;
    }
}

And then we will fetch all the entries of the h2o_feet measurement.

package com.gkatzioura.mapper.showcase;

import java.util.List;
import java.util.logging.Logger;

import org.influxdb.InfluxDB;
import org.influxdb.InfluxDBFactory;
import org.influxdb.impl.InfluxDBImpl;
import org.influxdb.impl.InfluxDBMapper;

public class InfluxDBMapperShowcase {

    private static final Logger LOGGER = Logger.getLogger(InfluxDBMapperShowcase.class.getName());

    public static void main(String[] args) {

        InfluxDB influxDB = InfluxDBFactory.connect("http://localhost:8086", "root", "root");

        InfluxDBMapper influxDBMapper = new InfluxDBMapper(influxDB);
        List h2OFeetMeasurements = influxDBMapper.query(H2OFeetMeasurement.class);

    }
}

After being successful in fetching the data, we will continue with persisting the data.

H2OFeetMeasurement h2OFeetMeasurement = new H2OFeetMeasurement();
h2OFeetMeasurement.setTime(Instant.now());
h2OFeetMeasurement.setLevelDescription("Just a test");
h2OFeetMeasurement.setLocation("London");
h2OFeetMeasurement.setWaterLevel(1.4d);

influxDBMapper.save(h2OFeetMeasurement);

List measurements = influxDBMapper.query(H2OFeetMeasurement.class);

H2OFeetMeasurement h2OFeetMeasurement1 = measurements.get(measurements.size()-1);
assert h2OFeetMeasurement1.getLevelDescription().equals("Just a test");

Apparently, fetching all the measurements to get the last entry is not the most efficient thing to do. In the upcoming tutorials, we are going to see how we use the InfluxDBMapper with advanced InfluxDB queries.

Let us know your thoughts in the comments.