composite-primary-key.adoc

Creating composite primary key

1. Create POJO that represents your composite key and provide converters for it:

   CommentsKey.java

   import lombok.Value;
   import org.springframework.core.convert.converter.Converter;
   import org.springframework.data.convert.ReadingConverter;
   import org.springframework.data.convert.WritingConverter;
   
   @Value
   public class CommentsKey {
   
       public final long pageId;
       public final long threadId;
   
       @WritingConverter
       public enum CommentsKeyToStringConverter implements Converter<CommentsKey, String> {
           INSTANCE;
   
           @Override
           public String convert(CommentsKey source) {
               return "comments::" + source.pageId + "::" + source.threadId;
           }
       }
   
       @ReadingConverter
       public enum StringToCommentsKeyConverter implements Converter<String, CommentsKey> {
           INSTANCE;
   
           @Override
           public CommentsKey convert(String source) {
               String[] split = source.split("::");
               if (split.length != 3) {
                   throw new IllegalArgumentException("Key can not be parsed: " + source);
               }
               long pageId = Long.parseLong(split[1]);
               long threadId = Long.parseLong(split[2]);
               return new CommentsKey(pageId, threadId);
           }
       }
   
   }

2. Use your custom key POJO in the document class:

   CommentsDocument.java

   import lombok.AllArgsConstructor;
   import lombok.Builder;
   import lombok.Value;
   import org.springframework.data.aerospike.mapping.Document;
   import org.springframework.data.aerospike.mapping.Field;
   import org.springframework.data.annotation.Id;
   
   import java.util.List;
   
   @Value
   @Document(collection = "demo-service-comments-set")
   @Builder(toBuilder = true)
   @AllArgsConstructor// Spring Data object creation can use all-args constructor instead of reflection which is much faster
   public class CommentsDocument {
   
       @Id
       private CommentsKey key;
   
       @Field
       private List<String> comments;
   
   }

3. Register custom converters in Aerospike configuration:

   AerospikeConfiguration.java

   @Configuration
   public class AerospikeConfiguration extends AbstractAerospikeDataConfiguration {
       // other code omitted
       @Override
       protected List<?> customConverters() {
           return List.of(
                   CommentsKey.CommentsKeyToStringConverter.INSTANCE,
                   CommentsKey.StringToCommentsKeyConverter.INSTANCE
           );
       }
   }

4. Create repository that uses your custom key:

   CommentsRepository.java

   import org.springframework.data.repository.CrudRepository;
   
   public interface CommentsRepository extends CrudRepository<CommentsDocument, CommentsKey> {
   }