Merge pull request spark-jobserver#239 from spark-jobserver/velvia/java-job-support

JavaSparkJob

Author: zeitos

job-server-api/src/spark.jobserver/JavaSparkJob.scala

@@ -0,0 +1,37 @@
+package spark.jobserver
+
+import com.typesafe.config.Config
+import org.apache.spark.api.java.JavaSparkContext
+import org.apache.spark.SparkContext
+
+/**
+ * A class to make Java jobs easier to write.  In Java:
+ * public class MySparkJob extends JavaSparkJob {
+ *   @override
+ *   public Object runJob(JavaSparkContext jsc, Config jobConfig) { ... }
+ * }
+ */
+class JavaSparkJob extends SparkJob {
+
+  def runJob(sc: SparkContext, jobConfig: Config): Any = {
+    runJob(new JavaSparkContext(sc), jobConfig);
+  }
+
+  def validate(sc: SparkContext, config: Config): SparkJobValidation = {
+    Option(invalidate(new JavaSparkContext(sc), config))
+      .map(err => SparkJobInvalid(err))
+      .getOrElse(SparkJobValid)
+  }
+
+  /**
+   * The main class that carries out the Spark job.  The results will be converted to JSON
+   * and emitted (but NOT persisted).
+   */
+  def runJob(jsc: JavaSparkContext, jobConfig: Config): Any = {}
+
+  /**
+   * Checks the config and returns an error message, or null if the config is fine.
+   * The error message will be returned to the user as a 404 HTTP error code.
+   */
+  def invalidate(jsc: JavaSparkContext, config: Config): String = { null }
+}

job-server-tests/src/main/java/spark.jobserver/JavaHelloWorldJob.java

@@ -0,0 +1,12 @@
+package spark.jobserver;
+
+import com.typesafe.config.Config;
+import org.apache.spark.api.java.JavaSparkContext;
+import spark.jobserver.JavaSparkJob;
+
+public class JavaHelloWorldJob extends JavaSparkJob {
+  @Override
+  public Object runJob(JavaSparkContext jsc, Config jobConfig) {
+    return("Hello World!");
+  }
+}