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    <p>Ok, after a bit of reading and diving into the world of design patterns I decided to do the following and share my experiences (please see my first post for resolving the references).</p> <p>For the persistence layer ([5], [6], [7], etc.) I used the Strategy-Pattern, but you can also call it <a href="http://java.sun.com/blueprints/corej2eepatterns/Patterns/DataAccessObject.html" rel="nofollow">DAOFactory-Pattern</a> if you want to google it. In connection with that I used the <a href="https://community.jboss.org/wiki/GenericDataAccessObjects" rel="nofollow">GenericDAO-Pattern</a>, which is very good explained in the book "Java Persistence with Hibernate".</p> <p>The Strategy-Pattern basically consists of an interface, in my case called <em>PersistenceStrategy</em> abstracting the actual persistence implementation. Further I have a service <em>PersistenceService</em> which wraps that Persistency Strategy.</p> <pre><code>public interface PersistenceStrategy { public void persist(BaseEntity object); ... } </code></pre> <p>The PersistenceService:</p> <pre><code>public class PersistenceService { private PersistenceStrategy persistenceStrategy; public void setPersistenceStrategy(PersistenceStrategy strategy) { this.persistenceStrategy = strategy; } public PersistenceStrategy getPersistenceStrategy() { return this.persistenceStrategy; } } </code></pre> <p>The actual persistence classes [6] and [7] (e.g. PersistenceStrategyHibernate) etc. implement this interface and I declared them as a Spring bean. Also I declared the PersistenceService as a bean. The actual PersistenceStrategy is them injected to the PersistenceService. Please note that this bean definition is in the actual persistence implementation in [5] and [6] for instance, not in the webapp project [4].</p> <pre><code>&lt;bean id="hibernatePersistenceStrategy" class="org.myProject.persistence.relational.HibernatePersistenceStrategy" /&gt; &lt;!-- PersistenceService is instantiated here with the actual persistence strategy implementation --&gt; &lt;bean id="persistenceService" class="org.myProject.persistence.PersistenceService"&gt; &lt;property name="persistenceStrategy" ref="hibernatePersistenceStrategy"&gt;&lt;/property&gt; &lt;/bean&gt; </code></pre> <p>In my webapp maven project [4] I do a reference to the actual persistence implementation, e.g. [5] or [6]. </p> <pre><code>&lt;dependency&gt; &lt;groupId&gt;org.myProject&lt;/groupId&gt; &lt;!-- this is where the persistence module is referenced. if you want to change the type of persistence you can do it here. --&gt; &lt;artifactId&gt;persistence-relational&lt;/artifactId&gt; &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt; &lt;/dependency&gt; </code></pre> <p>In my controller classes I can then reference the PersistenceService and the PersistenceStrategy.</p> <pre><code>@Controller public class NewDatasetController { @Autowired PersistenceStrategy persistenceStrategy; @RequestMapping("/") public String landing() { ... } } </code></pre> <p>These pattern are quite nice in my opinion. If you want to add something to this post please feel free.</p>
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    1. POHow to create an ABSTRACT persistence layer in Spring?
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    1. USmatthaeus
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    1. COI don't quite see a usage of PersistenceService
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      1. USYuriy Zubarev
    2. COThe advantage of the PersistenceService would be to have a central object to obtain the persistenceStrategy-object from. But you are right. I guess you can also rename the 'hibernatePersistenceStrategy'-Bean to 'persistenceStrategy' and @Autowire it where you need it and stay 'abstract' to the actual implementation in that way too.
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