When dealing with data stored in HBase, you are quick to come to a
conclusion, that it is extremaly inconvenient to reach to it
via HBase native API. It is very verbose and you always need to convert
between bytes and simple types – a pain.
While I was working on a project of mine, I thought, why not to easy
those pains and fetch real objects from HBase.
And that’s how this simplistic, hackish ORM came to life. It is no match
for projects like Kundera
(a JPA compliant solution), or n-orm. Nevertheless, it just suits my needs :)
Project sources are hosted on GitHub: https://github.com/zygm0nt/hbase-annotations
To make use of this, you need to have an entity class with annotations:
- @Column – with argument specifying column family and column name, ie.
@Column(“cf:column-name”) - @Id – will store row key in this property,
- and optionaly @Value – for Spring Expression Language, in case you
need to perform some extraction on the value.
Annotations should be on setter methods.
Now you have your model annotated and ready to be fetched from HBase.
The actual work is done with a service class, that should extend class
BaseHadoopInteraction just as class
SimpleHBaseClient does.
Then it is possible to just call:
Note that there are more methods you can use on BaseHadoopInteraction.
You can also do:
- scan
- scan with key ranges
- delete
What you won’t get from this simple ORM is:
- automatic object updating,
- nested objects,
- saving to HBase – ’cause I didn’t have a need for that,
Hope you’ll find this piece of code useful. If you see room for
improvements while staying in project’s scope – please drop me a
message.
And if you are searching for a full-fledged ORM solution for interacting with HBase, just head
straight to Kundera project website :)