JOhm

JOhm is a blazingly fast Object-Hash Mapping library for Java inspired by the awesome Ohm. The JOhm OHM is a modern-day avatar of the old ORM's like Hibernate with the difference being that we are not dealing with an RDBMS here but with a NoSQL rockstar.

JOhm is a library for storing objects in Redis, a persistent key-value database. JOhm is designed to be minimally-invasive and relies wholly on reflection aided by annotation hooks for persistence. The fundamental idea is to allow large existing codebases to easily plug into Redis without the need to extend framework base classes or provide excessive configuration metadata.

Durable data storage is available via the Redis Append-only file (AOF). The default persistence strategy is Snapshotting.

About this fork

The original JOhm is not maintained anymore, there's a lot of useful pull requests that are not being merged and the author is not responding.

I need JOhm in my projects, so I forked it and will maintain it here. Go ahead if you have pull requests to merge from the original repository, I will merge them asap.

I've already added support for enums, dates and some improvements like ignoring some field retrieval. I also already merged PR 39 which is useful for querying on multiple fields at the same time.

CHANGELOG

Use this fork

I will release a version of this JOhm fork every time I fix a bug or merge a PR. In order to use this fork you need to add a custom maven repository in your pom.xml:

<repositories>
    <repository>
        <id>johm-mvn-repo</id>
        <url>https://raw.github.com/agrison/johm/mvn-repo/</url>
        <snapshots>
            <enabled>true</enabled>
            <updatePolicy>always</updatePolicy>
        </snapshots>
    </repository>
</repositories>

Then just add the dependency to this JOhm version, last released version is currently 0.6.7 (last snapshot is 0.6.8-SNAPSHOT):

<dependency>
    <groupId>redis</groupId>
    <artifactId>johm</artifactId>
    <version>0.6.7</version>
    <type>jar</type>
</dependency>

JOhm currently uses Jedis 2.8.0

What can I do with JOhm?

JOhm is still in active development. The following features are currently available:

• Basic attribute persistence (String, Integer, etc...)
• Enums
• Auto-numeric Ids
• References
• Arrays
• Indexes
• Deletion
• List, Set, SortedSet and Map relationship
• Search on attributes, arrays, collections and references

Stay close! It is growing pretty fast!

How do I use it?

And this is a small example (getters and setters are not included for the sake of simplicity):

@Model
class User {
    @Id
    private Long id;
	@Attribute
	private String name;
	@Attribute
	@Indexed
	private int age;
	@Reference
	@Indexed
	private Country country;
	@CollectionList(of = Comment.class)
	@Indexed
	private List<Comment> comments;
	@CollectionSet(of = Item.class)
	@Indexed
	private Set<Item> purchases;
	@CollectionMap(key = Integer.class, value = Item.class)
    @Indexed
    private Map<Integer, Item> favoritePurchases;
    @CollectionSortedSet(of = Item.class, by = "price")
    @Indexed
    private Set<Item> orderedPurchases;
    @Array(of = Item.class, length = 3)
    @Indexed
    private Item[] threeLatestPurchases;
}

// The value() of @Model can be used to use a specific key in redis
// If not set then the Java Class<?>.getSimpleName() is used as default
@Model("Com")
class Comment {
    @Id
    private Long id;
	@Attribute
	private String text;
	@Attribute
	private Status status;
}

@Model
class Item {
    @Id
    private Long id;
	@Attribute
	private String name;
}

enum Status {
    WAITING_FOR_MODERATION, VALID, FLAGGED
}

Initiating JOhm:

JedisPool jedisPool = new JedisPool(new GenericObjectPoolConfig(), "localhost");
JOhm.setPool(jedisPool);

Creating a User and persisting it:

User someOne = new User();
someOne.setName("Someone");
someOne.setAge(30);
JOhm.save(someOne);

Loading a persisted User:

User storedUser = JOhm.get(User.class, 1);

You can avoid properties being loaded:

User userWithoutComments = JOhm.get(User.class, 1, "comments");

Checking if a User exists:

boolean user2Exists = JOhm.exists(User.class, 42);

Deleting a User:

JOhm.delete(User.class, 1);

Search for all users of age 30:

List<User> users = JOhm.find(User.class, "age", "30");

Search for all users of age 30, without returning their favorite purchases:

List<User> users = JOhm.find(User.class, "age", "30", "favoritePurchases");

Model with a reference:

User someOne = new User();
...
JOhm.save(someOne);

Country someCountry = new Country();
...
JOhm.save(country);

someOne.setCountry(someCountry);

Model with a list of nested models:

User someOne = new User();
...
JOhm.save(someOne);

Comment aComment = new Comment();
...
JOhm.save(aComment);

someOne.getComments().add(aComment);

Model with a set of nested models:

User someOne = new User();
...
JOhm.save(someOne);
	
Item anItem = new Item();
...
JOhm.save(anItem);
	
someOne.getPurchases().add(anItem);

For more usage examples check the tests.

And you are done!

How do I use it with Spring?

applicationContext.xml

<bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
	<property name="minIdle" value="1" />
	<property name="maxIdle" value="8" />
</bean>

<bean id="jedisPool" class="redis.clients.jedis.JedisPool">
	<constructor-arg index="0" ref="poolConfig" />
	<constructor-arg index="1" value="localhost" />
	<constructor-arg index="2" value="6379" />
	<constructor-arg index="3" value="2000" />
</bean>

<bean id="redisOhm" class="redis.clients.johm.JOhm" factory-method="setPool" scope="singleton" >
	<constructor-arg ref="jedisPool" />
</bean>

<bean id="userDao" class="com.mypackage.UserDaoImpl" />

And now you can use directly in your UserDaoImpl:

JOhm.expire(entity, seconds);

License

Copyright (c) 2010 Gaurav Sharma and Jonathan Leibiusky

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.