Htykuut

For one of our customers we have to generate a product catalog based on files provided by the client. So far we have stored the data in MongoDB via Morphia though are switching to Spring-Data-MongoDB (version 2.0.9) now.

In order to keep track of the changes done to products we keep the previous version of a product in a separate collection in order to provide some before and after view. To avoid code duplication the code basically inherits from the actual product. We agreed to store the previous version up to 90 days and afterwards we are eligible to remove it from our db.

The problem now is, that one of the fields (lastChange) was specified previously in Morphia as index with expiration day. Due to PreviousProduct inheriting this field from Product we have to use @CompoundIndex to create an index that way. Since Spring Data 1.6, however, defining an expiration timestamp on a compound index got removed.

Code-wise this looks as such:

Abstract base class:

@EqualsAndHashCode(exclude={"creationDate", "lastChange", "version"})

public abstract class MongoBaseEntity {



  @Id

  @Getter @Setter

  protected String id;



  @Getter

  @DiffIgnore

  protected Date creationDate;

  @Getter

  @DiffIgnore

  protected Date lastChange;



  @Version

  @DiffIgnore

  @Getter

  protected Long version;



  /**

   * Do not invoke. This method will be invoked by a custom {@link 

   * AbstractMongoEventListerner} listening for an {@link BeforeConvertEvent}

   */

  // @PrePersist

  public void prePersist() {

    creationDate = (creationDate == null) ? new Date() : creationDate;

    lastChange = (lastChange == null) ? creationDate : new Date();

  }



  @Override

  public abstract String toString();

}

Product class

// @Entity(value = "product", noClassnamesStored = true)

// @Indexes(@Index(fields = @Field("ownerUuid")))

@Document(collection = "product")

@Getter

@Setter

public class Product extends MongoBaseEntity {



  private String ean; // european article number

  private String upc; // universal product code

  private string gpc; // gloabal product classification code

  @Indexed

  private String ownerUuid;

  private String ownerName;

  ...

}

PreviousProduct class

// @Entity(value = "product-prev", noClassnamsStored = true)

// @Indexes({

//   @Index(fields = @Field("lastChange"), options = @IndexOptions(expireAfterSeconds = 7775000)), // 90 days

//   ...

// })

@Document(collection = "product-prev")

@CompoundIndexes({

  @CompoundIndex(name = "expIdx_lastChange", def = "{ 'lastChange': 1 }"), // expireAfterSeconds = 7775000 (90 days)

  ...

}

@Getter

@Setter

@ToString

public class PreviousProduct extends ProductEntity {

  ...

}

I kept the previous Morphia annotations in for clarity. Note further that there are multiple compound indices on the previous product though I omitted them as they are not part of the problem here IMO.

I do understand why the support of the field was removed, as potentially one could have attempted to specify an expiry timestamp on multiple fields, when MongoDB only supports expiration on a single field only, though, in this case the expiration should only be applied on a single field.

So, how can I define an expiration index on PreviousProduct in this case so that the document stored in PreviousProduct will be removed after 90 days?