Spring Batch: MultiResourceItemReader with custom ItemReader reads the same file ad infinitum

Question

I have a MultiResourceItemReader with a custom ItemReader as a delegate. The problem I'm facing is that when I launch the job, the same file is read over and over again.

This is the delegate class:

public class AllegatiReader implements ResourceAwareItemReaderItemStream<Allegato> {

    @PersistenceContext
    protected EntityManager em;

    private Resource resource;

    @Override
    public void close() throws ItemStreamException {
    }

    @Override
    public void open(ExecutionContext arg0) throws ItemStreamException {    
    }

    @Override
    public void update(ExecutionContext arg0) throws ItemStreamException {
    }

    @Override
    public Allegato read() throws Exception, UnexpectedInputException,
            ParseException, NonTransientResourceException {

        // DO SOMETHING ...     

        byte[] fileContent = new byte[(int) resource.getFile().length()];

        resource.getInputStream().read(fileContent);
        resource.getInputStream().close();

        allegato.getFile().setFile(fileContent);

        return allegato;
    }

    @Override
    public void setResource(Resource arg0) {
        this.resource = arg0;       
    }
}

Here is my Spring Batch XML configuration file:

<batch:job id="allegati" incrementer="jobParametersIncrementer">
    <batch:step id="allegati-import">
        <batch:tasklet>
            <batch:chunk reader="allegati-reader" writer="allegati-writer" commit-interval="1"/>
        </batch:tasklet>
    </batch:step>
</batch:job>

<bean id="allegati-reader" class="org.springframework.batch.item.file.MultiResourceItemReader" scope="step">
    <property name="resources" value="file:#{jobParameters['FILEPATH']}/*" />
    <property name="delegate" ref="allegati-filereader" />
</bean>

<bean id="allegati-writer" class="org.springframework.batch.item.database.JpaItemWriter">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<bean id="allegati-filereader" class="it.infogroup.vertenze.porting.reader.AllegatiReader" />

How can I tell Spring Batch to move to the next file?

Answer 1

Your custom reader has to show Spring Batch when all is done, see http://docs.spring.io/spring-batch/trunk/apidocs/org/springframework/batch/item/ItemReader.html#read--

Reads a piece of input data and advance to the next one. Implementations must return null at the end of the input data set.

in your case i would use an private attribute to save* the state for the resource of this reader instance is processed , it could be the Allegato object, but that seems to be a rather large one

*) your reader is stateful by design, so another state attribute should be no problem