# batch-processing: Chunk oriented Batch 1.0 processing

> The `batch-processing` quickstart shows how to use chunk oriented batch jobs to import a file to a database.

## What is it?

This quickstart simulates a file importation using batch jobs. To make it easy, this quickstart offers the user a way to generate files. The generated file can have its name and the number of records customized. The user can also specify if the file contains an error or not.

The job contains two tasks:

1. It imports the file using a chunk oriented approach.

   - The chunk size is set to `3`.

   - The `RecordsReader` is responsible for parsing the file and create an instance of `Contact`.

   - The `ContactsFormatter` applies the proper case to the contact name and it also applies a mask to the phone number.

   - Finally, `ContactsPersister` sends the contact instance to the database.

2. It logs the number of records imported.

The database schema defines that the column for name is unique. For that reason, any attempt to persist a duplicate value will throw an exception. On the second attempt to run the job, the `ChunkCheckpoint` provides information to skip the contacts that were already persisted.

## Considerations for Use in a Production Environment

H2 Database

  This quickstart uses the H2 database included with WildFly Application Server 13. It is a lightweight, relational example datasource that is used for examples only. It is not robust or scalable, is not supported, and should NOT be used in a production environment.

Datasource Configuration File

  This quickstart uses a `*-ds.xml` datasource configuration file for convenience and ease of database configuration. These files are deprecated in WildFly and should not be used in a production environment. Instead, you should configure the datasource using the Management CLI or Management Console. Datasource configuration is documented in the Configuration Guide.

## System Requirements

The application this project produces is designed to be run on WildFly Application Server 13 or later.

All you need to build this project is Java 8.0 (Java SDK 1.8) or later and Maven 3.3.1 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.

## Use of WILDFLY_HOME

In the following instructions, replace `WILDFLY_HOME` with the actual path to your WildFly installation. The installation path is described in detail here: Use of WILDFLY_HOME and JBOSS_HOME Variables.

## Start the WildFly Standalone Server

1. Open a terminal and navigate to the root of the WildFly directory.

2. Start the WildFly server with the default profile by typing the following command.

       $ WILDFLY_HOME/bin/standalone.sh

   Note | For Windows, use the `WILDFLY_HOME\bin\standalone.bat` script.

## Build and Deploy the Quickstart

1. Make sure you start the WildFly server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type the following command to build the artifacts.

       $ mvn clean package wildfly:deploy

This deploys the `batch-processing/target/batch-processing.war` to the running instance of the server.

You should see a message in the server log indicating that the archive deployed successfully.

## Access the Application

Access the running application in a browser at the following URL: http://localhost:8080/batch-processing/

You are presented with a simple form that allows you to generate sample files to be imported.

### Usage 1: Import the file without any errors

1. Click on Generate a new file and start import job button. This generates a new file with 10 unique records to be imported. The import job starts after the file is generated.

2. A table is displayed containing information about the task that was started. Click on the Update jobs list button and verify that the job was completed.

3. Investigate the console output. It shows that files with 10 records were processed, 3 records at a time.

       INFO  [org.jboss.as.quickstarts.batch.controller.BatchController] (default task-3) Starting to generate 10 in file /var/folders/j8/63sgdmbn5tqdkyw0tz6df53r0000gn/T/temp-file.txt
       INFO  [org.jboss.as.quickstarts.batch.controller.BatchController] (default task-3) File generated at /var/folders/j8/63sgdmbn5tqdkyw0tz6df53r0000gn/T/temp-file.txt
       INFO  [org.jboss.as.quickstarts.batch.job.listener.JobListener] (Batch Thread - 1) Job import-file - Execution #1 starting.
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsPersister] (Batch Thread - 1) No checkpoint detected. Cleaning the Database
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #1 - Changing name ZIqYKITxiM -> Ziqykitxim | phone  978913851 -> (978)-913-851
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #2 - Changing name JbHjnaThps -> Jbhjnathps | phone  095108018 -> (095)-108-018
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #3 - Changing name FJTlXRtCdR -> Fjtlxrtcdr | phone  286847939 -> (286)-847-939
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Preparing to persist 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Persisting 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #4 - Changing name mlmBABWzfL -> Mlmbabwzfl | phone  744478648 -> (744)-478-648
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #5 - Changing name jVlTYiBRMP -> Jvltyibrmp | phone  135063841 -> (135)-063-841
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #6 - Changing name DwEFbSjfQE -> Dwefbsjfqe | phone  404572175 -> (404)-572-175
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Preparing to persist 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Persisting 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #7 - Changing name niDXWwGJuQ -> Nidxwwgjuq | phone  949448390 -> (949)-448-390
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #8 - Changing name VZBArfowSe -> Vzbarfowse | phone  902370961 -> (902)-370-961
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #9 - Changing name aSpyWCWwje -> Aspywcwwje | phone  246977695 -> (246)-977-695
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Preparing to persist 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Persisting 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 1) Register #10 - Changing name TofTfbRBzI -> Toftfbrbzi | phone  868339088 -> (868)-339-088
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Preparing to persist 1 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 1) Persisting 1 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ReportBatchelet] (Batch Thread - 1) Imported 10 to Database
       INFO  [org.jboss.as.quickstarts.batch.job.listener.JobListener] (Batch Thread - 1) Job import-file - Execution #1 finished. Status: COMPLETED

### Usage 2: Import an error file and fix it

Now you will simulate a file with duplicate records. This will raise an exception and stop the processing. After that, you will fix the file and continue the importing where it stopped.

1. Mark the Generate a duplicate record checkbox and click on Generate a new file and start import job button. If you click on Update jobs list button, you will see that the job failed with the following Exit Status: `Error : org.hibernate.exception.ConstraintViolationException: could not execute statement`. This was caused because the job tried to insert a duplicate record at the Database. You will also see `org.h2.jdbc.JdbcSQLException: Unique index or primary key violation` exception stacktraces in the server log.

2. Next, you will fix the file and restart that job execution. Uncheck the Generate a duplicate record checkbox and click on Generate a new file button. This will generate the file without errors.

3. Click on Restart button in the last column for that job instance in the List of Jobs table. If you click on Update jobs list button, you will see that the job was completed.

4. Review the server logs and verify that the job started from the last checkpoint.

       INFO  [org.jboss.as.quickstarts.batch.job.RecordsReader] (Batch Thread - 3) Skipping to line 3 as marked by previous checkpoint

5. Investigate the console output.

       INFO  [org.jboss.as.quickstarts.batch.job.listener.JobListener] (Batch Thread - 3) Job import-file - Execution #3 starting.
       INFO  [org.jboss.as.quickstarts.batch.job.RecordsReader] (Batch Thread - 3) Skipping to line 3 as marked by previous checkpoint
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #4 - Changing name HdeqwzEjbA -> Hdeqwzejba | phone  686417040 -> (686)-417-040
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #5 - Changing name veEEbtpYTJ -> Veeebtpytj | phone  367981821 -> (367)-981-821
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #6 - Changing name bQIKTUyqMW -> Bqiktuyqmw | phone  103363182 -> (103)-363-182
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Preparing to persist 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Persisting 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #7 - Changing name KVLIGXhCry -> Kvligxhcry | phone  117327691 -> (117)-327-691
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #8 - Changing name PBAZgernHy -> Pbazgernhy | phone  066203468 -> (066)-203-468
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #9 - Changing name DGtNZdteGB -> Dgtnzdtegb | phone  908779587 -> (908)-779-587
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Preparing to persist 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Persisting 3 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.ContactsFormatter] (Batch Thread - 3) Register #10 - Changing name mhmIHhZMhv -> Mhmihhzmhv | phone  094518410 -> (094)-518-410
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Preparing to persist 1 contacts
       INFO  [org.jboss.as.quickstarts.batch.job.listener.PersistListener] (Batch Thread - 3) Persisting 1 contacts
       WARN  [org.jberet] (Batch Thread - 3) JBERET000018: Could not find the original step execution to restart.  Current step execution id: 0, step name: reportBatchelet
       INFO  [org.jboss.as.quickstarts.batch.job.ReportBatchelet] (Batch Thread - 3) Imported 10 to Database
       INFO  [org.jboss.as.quickstarts.batch.job.listener.JobListener] (Batch Thread - 3) Job import-file - Execution #3 finished. Status: COMPLETED

### Usage 3: Import an error file and do not fix the errors

1. Check the Generate a duplicate record checkbox and click on Generate a new file ans start import job button. If you click on Update jobs list button, you will see that the job failed with the following Exit Status: `Error : org.hibernate.exception.ConstraintViolationException: could not execute statement`. This was caused because you tried to insert a duplicate record at the Database.

2. This time you will not fix the file. Just click on Restart button again. If you click on Update jobs list button, you will see that the job was marked as `ABANDONED` this time because it was restarted once. Notice that there is a new parameter: `restartedOnce=true`. This behavior was implemented in `JobListener` for demonstration purposes, to prevent a `FAILED` job from being restarted twice.

## Server Log: Expected Warnings and Errors

You will see the following warnings in the server log. You can ignore these warnings.

    WFLYJCA0091: -ds.xml file deployments are deprecated. Support may be removed in a future version.

    HHH000431: Unable to determine H2 database version, certain features may not work

## Undeploy the Quickstart

When you are finished testing the quickstart, follow these steps to undeploy the archive.

1. Make sure you start the WildFly server as described above.

2. Open a terminal and navigate to the root directory of this quickstart.

3. Type this command to undeploy the archive:

       $ mvn wildfly:undeploy

## Run the Quickstart in Red Hat JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts or run the Arquillian tests in Red Hat JBoss Developer Studio or from Eclipse using JBoss tools. For general information about how to import a quickstart, add a WildFly server, and build and deploy a quickstart, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts.

## Debug the Application

If you want to debug the source code of any library in the project, run the following command to pull the source into your local repository. The IDE should then detect it.

    $ mvn dependency:sources