Messing with Apache Spark

SparkTest.java

public final class SparkTest {
    private JavaSparkContext _spark;
    private int slices;
    
    public static void main(String[] args) throws Exception {
        int slices = (args.length == 1) ? Integer.parseInt(args[0]) : 2;
        
        SparkConf conf = new SparkConf().setAppName("SparkPi");
        JavaSparkContext spark = new JavaSparkContext(conf)
        
        SparkTest(spark, slices);
    }
    
    public SparkTest(JavaSparkContext spark, int slices) {
        _spark = spark;
        _slices = slices;
    }
    
    public float getPi(){
        int slices = _slices;
        int n = 100000 * slices;
        List<Integer> l = new ArrayList<Integer>(n);
        for (int i = 0; i < n; i++) {
            l.add(i);
        }

        JavaRDD<Integer> dataSet = jsc.parallelize(l, slices);
    
        int count = dataSet.map(new Function<Integer, Integer>() {
          @Override
          public Integer call(Integer integer) {
            double x = Math.random() * 2 - 1;
            double y = Math.random() * 2 - 1;
            return (x * x + y * y < 1) ? 1 : 0;
          }
        }).reduce(new Function2<Integer, Integer, Integer>() {
          @Override
          public Integer call(Integer integer, Integer integer2) {
            return integer + integer2;
          }
        });
        
        return 4.0 * count / n;
    }
}

public class IntegrationTests {
    @Test
    public void shouldWork() {
       SparkConf conf = new SparkConf().setAppName("TestApp").setMaster("local");
       JavaSparkContext spark = new JavaSparkContext(conf);
       int slices = 300;
       
       interview = new SparkTest(spark, slices);
       
       Assert.assertEquals(3.14, interview.getPi(), 0.001);
    }
}