# tJava properties for Apache Spark Streaming

These properties are used to configure tJava running in the Spark Streaming Job framework.

The Spark Streaming tJava component belongs to the Custom Code family.

This component is available in Talend Real Time Big Data Platform and Talend Data Fabric.

## Basic settings

| Schema et Edit Schema | A schema is a row description. It defines the number of fields<br>(columns) to be processed and passed on to the next component. When you create a Spark<br>Job, avoid the reserved word line when naming the<br>fields.<br><br>Click Edit<br>schema to make changes to the schema. If the current schema is of the Repository type, three options are available:<br><br><ul> <li> <p> <span>View schema</span>: choose this                option to view the schema only.</p> </li> <li> <p> <span>Change to built-in property</span>:                choose this option to change the schema to <span>Built-in</span> for local changes.</p> </li> <li> <p> <span>Update repository connection</span>:                choose this option to change the schema stored in the repository and decide whether                to propagate the changes to all the Jobs upon completion. If you just want to                propagate the changes to the current Job, you can select <span>No</span> upon completion and choose this schema metadata                again in the <span>Repository Content</span>                window.</p> </li> </ul><br><br>Note that if the input value of any non-nullable primitive field is<br>null, the row of data including that field will be rejected. |
| --- | --- |
|  | Built-In: You create and store the schema locally for this component<br>only. |
|  | Repository: You have already created the schema and stored it in the<br>Repository. You can reuse it in various projects and Job designs. |
| Code | Type in the Java code you want to execute to process the incoming RDD<br>from the input link or even create new RDDs out of this input one.<br><br>You need to leverage the schema, the link and the component name to<br>write the custom code. For example, if this component is labeled<br>*tJava\_1* and the connection to it<br>is labeled *row1*, then the class of<br>the input RDD is *row1Struct* and the<br>input RDD itself is available with the *rdd\_tJava\_1* variable.<br><br>For more detailed instructions, see the default comment provided in<br>the Code field of this<br>component.<br><br>For further information about Spark Java API, see<br>Apache's Spark documentation in https://spark.apache.org/docs/latest/api/java/index.html. |

## Advanced settings

| Classes | Define the classes that you need to use in the code written in the Code field in the Basic settings<br>view.<br><br>It is recommended to define new classes in this field, instead of in the Code field, so as to avoid<br>eventual exceptions in serialization. |
| --- | --- |
| Import | Enter the Java code to import, if necessary, external libraries<br>used in the Code field of the Basic settings view. |

## Usage

| **Usage rule** | This component is used as an end component and requires an input link. |
| --- | --- |
| Code example | In the Code field of the Basic settings view,<br>enter the following code to create an output RDD by using custom transformations on the<br>input RDD. mapInToOut is a class to be defined in the<br>Classes field in the Advanced settings<br>view.<br><br>```<br>outputrdd_tJava_1 = rdd_tJava_1.map(new mapInToOut(job));<br>```<br><br>In<br>the Classes field of the Advanced settings<br>view, enter the following code to define the mapInToOut<br>class:<br><br>```<br>public static class mapInToOut implements<br>org.apache.spark.api.java.function.Function<inputStruct,RecordOut_tJava_1>{<br><br>private ContextProperties context = null;<br>private java.util.List<org.apache.avro.Schema.Field> fieldsList;<br>		<br>public mapInToOut(JobConf job) {<br>	   this.context = new ContextProperties(job);<br>}<br>		<br>@Override<br>public RecordOut_tJava_1 call(inputStruct origStruct) {		<br>			<br>	 if (fieldsList == null) {<br>	     this.fieldsList = (new inputStruct()).getSchema()<br>			.getFields();<br>	 }<br><br>	 RecordOut_tJava_1 value = new RecordOut_tJava_1();<br><br>	 for (org.apache.avro.Schema.Field field : fieldsList) {<br>	      value.put(field.pos(), origStruct.get(field.pos()));<br>	 }<br><br>	 return value;		<br>			<br>}<br>}<br>``` |
| Spark Connection | In the Spark<br>Configuration tab in the Run<br>view, define the connection to a given Spark cluster for the whole Job. In<br>addition, since the Job expects its dependent jar files for execution, you must<br>specify the directory in the file system to which these jar files are<br>transferred so that Spark can access these files:<br><br><ul> <li> <div> <span>Yarn mode</span> (Yarn client or Yarn cluster):<ul> <li> <p>When using Google Dataproc, specify a bucket in the                                            <span>Google Storage staging bucket</span>                                        field in the <span>Spark configuration</span>                                        tab.</p> </li> <li> <p>When using HDInsight, specify the blob to be used for Job                                        deployment in the <span>Windows Azure Storage                                            configuration</span> area in the <span>Spark                                            configuration</span> tab.</p> </li> <li>When using Altus, specify the S3 bucket or the Azure                                    Data Lake Storage for Job deployment in the <span>Spark                                        configuration</span> tab.</li> <li>When using Qubole, add a                                        <span>tS3Configuration</span> to your Job to write                                    your actual business data in the S3 system with Qubole. Without                                        <span>tS3Configuration</span>, this business data is                                    written in the Qubole HDFS system and destroyed once you shut                                    down your cluster.</li> <li> <p>When using on-premise distributions, use the configuration component                                        corresponding to the file system your cluster is using.                                        Typically, this system is HDFS and so use <span></span>.</p> </li> </ul> </div> </li> <li> <p> <span>Standalone mode</span>: use the                            configuration component corresponding to the file system your cluster is                            using, such as <span>tHDFSConfiguration</span> or <span>tS3Configuration</span>.</p> <p>If you are using Databricks without any configuration component present                            in your Job, your business data is written directly in DBFS (Databricks                            Filesystem).</p> </li> </ul><br><br>This connection is effective on a per-Job basis. |