gemfire-spark-connector/gemfire-spark-demos/basic-demos/src/main/java/demo/OQLJavaDemo.java

package demo;

import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.DataFrame;
import org.apache.spark.sql.SQLContext;
import static io.pivotal.gemfire.spark.connector.javaapi.GemFireJavaUtil.*;


/**
 * This Spark application demonstrates how to get region data from GemFire using GemFire
 * OQL Java API. The result is a Spark DataFrame.
 * <p>
 * In order to run it, you will need to start a GemFire cluster, and run demo PairRDDSaveJavaDemo
 * first to create some data in the region.
 * <p>
 * Once you compile and package the demo, the jar file basic-demos_2.10-0.5.0.jar
 * should be generated under gemfire-spark-demos/basic-demos/target/scala-2.10/. 
 * Then run the following command to start a Spark job:
 * <pre>
 *   <path to spark>/bin/spark-submit --master=local[2] --class demo.OQLJavaDemo \
 *       <path to>/basic-demos_2.10-0.5.0.jar <locator host>:<port>
 * </pre>
 */
public class OQLJavaDemo {

  public static void main(String[] argv) {

    if (argv.length != 1) {
      System.err.printf("Usage: OQLJavaDemo <locators>\n");
      return;
    }

    SparkConf conf = new SparkConf().setAppName("OQLJavaDemo");
    conf.set(GemFireLocatorPropKey, argv[0]); // "192.168.1.47[10335]"
    JavaSparkContext sc = new JavaSparkContext(conf);
    SQLContext sqlContext = new org.apache.spark.sql.SQLContext(sc);
    DataFrame df = javaFunctions(sqlContext).gemfireOQL("select * from /str_str_region");
    System.out.println("======= DataFrame =======\n");
    df.show();
    sc.stop();
  }
}