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Map of Objects using ElementCollection (hacked)
Using Jpa Converters, it is possible to convert Object class to binary array. In this scenario JpaExampleEmd class is not entity and neither embedded.
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@Data
public class JpaExampleEmd implements Serializable {
private static final long serialVersionUID = 1L;
@VerifyKey
@NotNull
private ExampleKey key;
private Boolean primed;
@NotNull
private Date timeStamp;
}
@Converter(autoApply = true)
public class ExampleConverter implements AttributeConverter<JpaExampleEmd, byte[]> {
@Override
public byte[] convertToDatabaseColumn(JpaExampleEmd attribute) {
return SerializationUtils.serialize(attribute);
}
@Override
public JpaExampleEmd convertToEntityAttribute(byte[] dbData) {
return (JpaExampleEmd) SerializationUtils.deserialize(dbData);
}
}
@Entity
@Table(name = "ExampleObjMapEc")
@Data
public class JpaExampleObjMapEc implements Serializable {
private static final long serialVersionUID = 1L;
@EmbeddedId
@VerifyKey
@NotNull
private ExampleKey key;
@ElementCollection
@Lob
private Map<@NotNull String, @NotNull JpaExampleEmd> examples;
} |
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- Move to Hibernate with EclipseLink tables is possible using Jpa Converters.
- The presence of longblob types used to store whole objects is an issues, it is readable only by Java language or by any other language compatible with Java binary code. I am not sure if a db-migrator can handle that.
- Document databases store all information for a given object in a single instance in the database, and every stored object can be different from every other. So, using MongoDB/Cassandra will solve all issues.
JpaRepositoryandMongoRepositoryextendCrudRepositoryand expose the capabilities of the underlying persistence technology in addition to the rather generic persistence technology-agnostic interfaces like e.g.CrudRepository.
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