CODEWITHSUNDEEP
javaspringmongodbspring-batchspring-data-mongodb
vignesh294
vignesh294

Reputation: 782

How to update and insert a document using MongoItemWriter in Spring Batch?

In a Spring Batch project involving reading and writing to MongoDB, writing to MongoDB using MongoItemWriter is configured like this:

<batch:job id=“someJob”>
    <batch:step id="step1">
        <batch:tasklet>
            <batch:chunk reader=“reader”
                writer=“writer”
                processor=“processor” commit-interval="10" />
        </batch:tasklet>
    </batch:step>
</batch:job>

The writer bean is configured like this: 

<bean id="writer"
    class="org.springframework.batch.item.data.MongoItemWriter">
    <property name="template" ref="mongoTemplate" />
    <property name="collection"
        value="XYZCollection" />
</bean>

Then we have the model:

public class Sample {

    @Id
    private ObjectId id;

    @Field(“Field1”)
    private String field1;

    @PersistenceConstructor
    public Sample() { }

    // getter and setters

}

Finally, from the processor, the object of the class whose model makes up the MongoDB document is returned, so that the ItemWriter will pick it up for inserting into the database:

public class Processor implements ItemProcessor<Sample, Sample> {

    @Override
    public Sample process(Sample sampleItem) throws Exception {
        Sample updatedSampleItem = updateSampleItem(sampleItem);
        Sample newSampleItem = createSampleItem(sampleItem);
        return newSampleItem;
    }
}

Versions used: - spring-core 5.1.3.RELEASE - spring-batch 4.1.0.RELEASE - spring-data-mongodb 2.1.3.RELEASE

Now, this saves the newSampleItem into XYZCollection as it has to. The requirement is to make Spring-Batch update the sampleItem that got read and then create a new document for the newSampleItem object. Is it possible to do so? If yes, how?

Upvotes: 4

Views: 3815

Answers (1)

Mahmoud Ben Hassine
Mahmoud Ben Hassine

Reputation: 31600

You can use a CompositeItemWriter with two writers, one that updates the item and another one that inserts the new document:

  • For inserts, you can use the writer you already have.
  • For updates, you need to create a new writer that extends MongoItemWriter and override doWrite to update the item. This is because the MongoItemWriter allows to either remove or save a document, but not update a document.

Then use both writers as delegates to the CompositeItemWriter.

Upvotes: 2

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