Spring Data uses heavily Spring framework's core functionality, such as the IoC container, resource abstract or AOP infrastructure. While it is not important to know the Spring APIs, understanding the concepts behind them is. At a minimum, the idea behind IoC should be familiar. These being said, the more knowledge one has about the Spring, the faster she will pick Spring Data Key Value. Besides the very comprehensive (and sometimes disarming) documentation that explains in detail the Spring Framework, there are a lot of articles, blog entries and books on the matter - take a look at the Spring framework home page for more information. In general, this should be the starting point for developers wanting to try Spring DKV.

NoSQL stores have taken the storage world by storm. It is a vast domain with a plethora of solutions, terms and patterns (to make things worth even the term itself has multiple meanings). While some of the principles are common, it is crucial that the user is familiar to some degree with the stores supported by SDKV. The best way to get acquainted to this solutions is to read their documentation and follow their examples - it usually doesn't take more then 5-10 minutes to go through them and if you are coming from an RDMBS-only background many times these exercises can be an eye opener.

Unfortunately the SDKV project is very young and there are no samples available yet. However we are working on them and plan to make them available as soon as possible. In the meantime however, one can use our test suite as a code example (assuming the documentation is not enough) - we provide extensive integration tests for our code base.

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There are a couple additional properties on the RiakTemplate that can be changed from their defaults. If you want to specify your own ConversionService to use when converting objects for storage inside Riak, then set it on the "conversionService" property:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="conversionService" class="com.mycompany.convert.MyConversionService"/> 
    <bean id="riakTemplate" class="org.springframework.data.keyvalue.riak.core.RiakTemplate" 
          p:defaultUri="http://localhost:8098/riak/{bucket}/{key}"
          p:mapReduceUri="http://localhost:8098/mapred"
          p:conversionService-ref="conversionService"/>

</beans>

Depending on the application, it might be useful to set default Quality-of-Service parameters. In Riak paralance, these are the "dw", "w", and "r" parameters. They can be set to an integer representing the number of vnodes that need to report having received the data before declaring the operation a success, or the string "one", "all", or (the default) "quorum". These values can be overridden by passing a different set of QosParameters to the set/get operation you're performing.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="qos" class="org.springframework.data.keyvalue.riak.core.RiakQosParameters"
          p:durableWriteThreshold="all"
          p:writeThreshold="all"/>
    <bean id="riakTemplate" class="org.springframework.data.keyvalue.riak.core.RiakTemplate" 
          p:defaultUri="http://localhost:8098/riak/{bucket}/{key}"
          p:mapReduceUri="http://localhost:8098/mapred"
          p:defaultQosParameters-ref="qos"/>

</beans>

It might also be necessary to replace the default ExecutorService (by default a cached ThreadPoolExecutor) with an executor you've explicitly configured. Set your ExecutorService on the template's "executorService" property.

To store data in Riak, use one of the six different set methods:

import org.springframework.data.keyvalue.riak.core.RiakTemplate;

public class Example {

    @Autowired
    RiakTemplate riak;

    public void setData(String bucket, String key, String data) throws Exception {
        riak.set(bucket, key, data); // Set as Content-Type: text/plain
        riak.setAsBytes(bucket, key, data.getBytes()); // Set as Content-Type: application/octet-stream
    }
  
    public void setData(String bucket, String key, MyPojo data) throws Exception {
        riak.set(bucket, key, data); // Converted to JSON automatically, Content-Type: application/json
    }

}
        

Additionally, there is a setWithMetaData method that takes a Map of metadata that will be set as the outgoing HTTP headers. To set custom metadata, your key should be prefixed with X-Riak-Meta- e.g. X-Riak-Meta-Custom-Header.

Retrieving data from Riak is just as easy. There are actually 13 different get methods on RiakTemplate that give the developer a wide range options for accessing and converting your data.

Assuming you've stored a POJO using an appropriate set method, you can retrieve that object from Riak using a get:

import org.springframework.data.keyvalue.riak.core.RiakTemplate;

  public class Example {

      @Autowired
      RiakTemplate riak;

      public void getData(String bucket, String key) throws Exception {
          // What you get depends on Content-Type. 
          // application/json=Map, text/plain=String, etc...
          Object o = riak.get(bucket, key); 
        
          // If your entry is Content-Type: application/json...
          // It will automatically be converted when retrieved.
          MyPojo s = riak.getAsType(bucket, key, MyPojo.class);
        
          // If your entry is Content-Type: application/octet-stream,
          // you can access the raw bytes.
          byte[] b = riak.getAsBytes(bucket, key); // No conversion at all
      }

  }