Spring Batch Component

Since Camel 2.10

Only producer is supported

The Spring Batch component and support classes provide integration bridge between Camel and Spring Batch infrastructure.

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

<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

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.

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

The Spring Batch component supports 5 options, which are listed below.

Name Description Default Type

jobLauncher (producer)

Explicitly specifies a JobLauncher to be used.

JobLauncher

jobRegistry (producer)

Explicitly specifies a JobRegistry to be used.

JobRegistry

basicPropertyBinding (advanced)

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

The Spring Batch endpoint is configured using URI syntax:

spring-batch:jobName

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

jobName

Required The name of the Spring Batch job located in the registry.

String

Query Parameters (6 parameters):

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

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

basicPropertyBinding (advanced)

Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

Spring Boot Auto-Configuration

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

<dependency>
  <groupId>org.apache.camel.springboot</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 6 options, which are listed below.

Name Description Default Type

camel.component.spring-batch.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.spring-batch.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

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.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

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:

from("direct:startBatch").to("spring-batch:myJob");

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

from("direct:startBatch").to("spring-batch:myJob?jobLauncherRef=myJobLauncher");

A 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.

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.

<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.

<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 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 Direct endpoint and the Simple expression language.

<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.

<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>