[[spring-batch-component]]
== Spring Batch Component

*Available as of Camel version 2.10*

The *spring-batch:* component and support classes provide integration
bridge between Camel and http://www.springsource.org/spring-batch[Spring
Batch] infrastructure.

Maven users will need to add the following dependency to their `pom.xml`
for this component:

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-spring-batch</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

### URI format

[source,java]
------------------------------
spring-batch:jobName[?options]
------------------------------

Where *jobName* represents the name of the Spring Batch job located in
the Camel registry. Alternatively if a JobRegistry is provided it will be used 
to locate the job instead.

WARNING:This component can only be used to define producer endpoints, which
means that you cannot use the Spring Batch component in a `from()`
statement.

### Options




// component options: START
The Spring Batch component supports 3 options, which are listed below.



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *jobLauncher* (producer) | Explicitly specifies a JobLauncher to be used. |  | JobLauncher
| *jobRegistry* (producer) | Explicitly specifies a JobRegistry to be used. |  | JobRegistry
| *resolveProperty Placeholders* (advanced) | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | boolean
|===
// component options: END








// endpoint options: START
The Spring Batch endpoint is configured using URI syntax:

----
spring-batch:jobName
----

with the following path and query parameters:

==== Path Parameters (1 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *jobName* | *Required* The name of the Spring Batch job located in the registry. |  | String
|===


==== Query Parameters (4 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *jobFromHeader* (producer) | Explicitly defines if the jobName should be taken from the headers instead of the URI. | false | boolean
| *jobLauncher* (producer) | Explicitly specifies a JobLauncher to be used. |  | JobLauncher
| *jobRegistry* (producer) | Explicitly specifies a JobRegistry to be used. |  | JobRegistry
| *synchronous* (advanced) | Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). | false | boolean
|===
// endpoint options: END
// spring-boot-auto-configure options: START
=== Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

[source,xml]
----
<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-spring-batch-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>
----


The component supports 4 options, which are listed below.



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *camel.component.spring-batch.enabled* | Enable spring-batch component | true | Boolean
| *camel.component.spring-batch.job-launcher* | Explicitly specifies a JobLauncher to be used. The option is a org.springframework.batch.core.launch.JobLauncher type. |  | String
| *camel.component.spring-batch.job-registry* | Explicitly specifies a JobRegistry to be used. The option is a org.springframework.batch.core.configuration.JobRegistry type. |  | String
| *camel.component.spring-batch.resolve-property-placeholders* | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | Boolean
|===
// spring-boot-auto-configure options: END






### Usage

When Spring Batch component receives the message, it triggers the job
execution. The job will be executed using the
`org.springframework.batch.core.launch.JobLaucher` instance resolved
according to the following algorithm:

* if `JobLauncher` is manually set on the component, then use it.
* if `jobLauncherRef` option is set on the component, then search Camel
Registry for the `JobLauncher` with the given name.
*Deprecated and will be removed in Camel 3.0!*
* if there is `JobLauncher` registered in the Camel
Registry under *jobLauncher* name, then use it.
* if none of the steps above allow to resolve the `JobLauncher` and
there is exactly one `JobLauncher` instance in the Camel
Registry, then use it.

All headers found in the message are passed to the `JobLauncher` as job
parameters. `String`, `Long`, `Double` and `java.util.Date` values are
copied to the `org.springframework.batch.core.JobParametersBuilder` -
other data types are converted to Strings.

### Examples

Triggering the Spring Batch job execution:

[source,java]
---------------------------------------------------
from("direct:startBatch").to("spring-batch:myJob");
---------------------------------------------------

Triggering the Spring Batch job execution with the `JobLauncher` set
explicitly.

[source,java]
--------------------------------------------------------------------------------
from("direct:startBatch").to("spring-batch:myJob?jobLauncherRef=myJobLauncher");
--------------------------------------------------------------------------------

Starting from the Camel *2.11.1* `JobExecution` instance returned by the
`JobLauncher` is forwarded by the `SpringBatchProducer` as the output
message. You can use the `JobExecution` instance to perform some
operations using the Spring Batch API directly.

[source,java]
---------------------------------------------------------------------------------------------------
from("direct:startBatch").to("spring-batch:myJob").to("mock:JobExecutions");
...
MockEndpoint mockEndpoint = ...;
JobExecution jobExecution = mockEndpoint.getExchanges().get(0).getIn().getBody(JobExecution.class);
BatchStatus currentJobStatus = jobExecution.getStatus();
---------------------------------------------------------------------------------------------------

### Support classes

Apart from the Component, Camel Spring Batch provides also support
classes, which can be used to hook into Spring Batch infrastructure.

#### CamelItemReader

`CamelItemReader` can be used to read batch data directly from the Camel
infrastructure.

For example the snippet below configures Spring Batch to read data from
JMS queue.

[source,xml]
-----------------------------------------------------------------------------------------------
<bean id="camelReader" class="org.apache.camel.component.spring.batch.support.CamelItemReader">
  <constructor-arg ref="consumerTemplate"/>
  <constructor-arg value="jms:dataQueue"/>
</bean>

<batch:job id="myJob">
  <batch:step id="step">
    <batch:tasklet>
      <batch:chunk reader="camelReader" writer="someWriter" commit-interval="100"/>
    </batch:tasklet>
  </batch:step>
</batch:job>
-----------------------------------------------------------------------------------------------

#### CamelItemWriter

`CamelItemWriter` has similar purpose as `CamelItemReader`, but it is
dedicated to write chunk of the processed data.

For example the snippet below configures Spring Batch to read data from
JMS queue.

[source,xml]
-----------------------------------------------------------------------------------------------
<bean id="camelwriter" class="org.apache.camel.component.spring.batch.support.CamelItemWriter">
  <constructor-arg ref="producerTemplate"/>
  <constructor-arg value="jms:dataQueue"/>
</bean>

<batch:job id="myJob">
  <batch:step id="step">
    <batch:tasklet>
      <batch:chunk reader="someReader" writer="camelwriter" commit-interval="100"/>
    </batch:tasklet>
  </batch:step>
</batch:job>
-----------------------------------------------------------------------------------------------

#### CamelItemProcessor

`CamelItemProcessor` is the implementation of Spring Batch
`org.springframework.batch.item.ItemProcessor` interface. The latter
implementation relays on
http://camel.apache.org/request-reply.html[Request Reply pattern] to
delegate the processing of the batch item to the Camel infrastructure.
The item to process is sent to the Camel endpoint as the body of the
message.

For example the snippet below performs simple processing of the batch
item using the http://camel.apache.org/direct.html[Direct endpoint] and
the http://camel.apache.org/simple.html[Simple expression language].

[source,xml]
-------------------------------------------------------------------------------------------------------------
<camel:camelContext>
  <camel:route>
    <camel:from uri="direct:processor"/>
    <camel:setExchangePattern pattern="InOut"/>
    <camel:setBody>
      <camel:simple>Processed ${body}</camel:simple>
    </camel:setBody>
  </camel:route>
</camel:camelContext>

<bean id="camelProcessor" class="org.apache.camel.component.spring.batch.support.CamelItemProcessor">
  <constructor-arg ref="producerTemplate"/>
  <constructor-arg value="direct:processor"/>
</bean>

<batch:job id="myJob">
  <batch:step id="step">
    <batch:tasklet>
      <batch:chunk reader="someReader" writer="someWriter" processor="camelProcessor" commit-interval="100"/>
    </batch:tasklet>
  </batch:step>
</batch:job>
-------------------------------------------------------------------------------------------------------------

#### CamelJobExecutionListener

`CamelJobExecutionListener` is the implementation of the
`org.springframework.batch.core.JobExecutionListener` interface sending
job execution events to the Camel endpoint.

The `org.springframework.batch.core.JobExecution` instance produced by
the Spring Batch is sent as a body of the message. To distinguish
between before- and after-callbacks `SPRING_BATCH_JOB_EVENT_TYPE` header
is set to the `BEFORE` or `AFTER` value.

The example snippet below sends Spring Batch job execution events to the
JMS queue.

[source,xml]
-----------------------------------------------------------------------------------------------------------------------
<bean id="camelJobExecutionListener" class="org.apache.camel.component.spring.batch.support.CamelJobExecutionListener">
  <constructor-arg ref="producerTemplate"/>
  <constructor-arg value="jms:batchEventsBus"/>
</bean>

<batch:job id="myJob">
  <batch:step id="step">
    <batch:tasklet>
      <batch:chunk reader="someReader" writer="someWriter" commit-interval="100"/>
    </batch:tasklet>
  </batch:step>
  <batch:listeners>
    <batch:listener ref="camelJobExecutionListener"/>
  </batch:listeners>
</batch:job>
-----------------------------------------------------------------------------------------------------------------------
