Real-time analytics with Nashorn and Apache Flink

In the world of big data, real-time analytics is becoming increasingly important. Businesses need the ability to analyze data as it streams in, allowing for faster and more informed decisions. In this blog post, we will explore how you can leverage the power of Nashorn and Apache Flink to perform real-time analytics.

What is Nashorn?

Nashorn is the JavaScript engine that was introduced in JDK 8. It allows developers to embed JavaScript in Java applications, making it possible to run JavaScript code seamlessly alongside Java code. Nashorn provides a high-performance execution environment for JavaScript, making it an appealing choice for running real-time analytics.

Apache Flink is an open-source stream processing framework. It allows you to process and analyze data streams in real-time, providing low-latency and high-throughput processing capabilities. Flink’s design makes it highly scalable and fault-tolerant, making it an ideal choice for real-time analytics applications.

By combining Nashorn and Apache Flink, you can achieve real-time analytics capabilities with the flexibility and power of JavaScript. Thanks to Nashorn’s seamless integration with Java, you can easily write JavaScript functions that can be used within your Flink applications.

Here’s an example code snippet that demonstrates how to use Nashorn with Apache Flink:

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.TimeCharacteristic;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.SourceFunction;

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class NashornFlinkExample {

    public static void main(String[] args) throws Exception {
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

        env.addSource(new SourceFunction<String>() {
            @Override
            public void run(SourceContext<String> sourceContext) throws Exception {
                // Your data source implementation
            }

            @Override
            public void cancel() {
                // Your cancellation logic
            }
        })
        .map(new MapFunction<String, Tuple2<String, Integer>>() {
            @Override
            public Tuple2<String, Integer> map(String value) throws Exception {
                ScriptEngineManager manager = new ScriptEngineManager();
                ScriptEngine engine = manager.getEngineByName("nashorn");
                engine.eval("var jsFunction = function(val) { return val + 1; }");

                Invocable invocable = (Invocable) engine;
                int result = (int) invocable.invokeFunction("jsFunction", Integer.parseInt(value));

                return Tuple2.of(value, result);
            }
        })
        .print();

        env.execute("Nashorn Flink Example");
    }
}

Conclusion

Real-time analytics is crucial for businesses to react quickly to changing situations and make data-driven decisions. By combining Nashorn and Apache Flink, you can harness the power of JavaScript to perform real-time analytics on data streams with ease. This allows you to leverage existing JavaScript skills and libraries, while benefiting from Flink’s scalability and fault-tolerance.

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