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POBusiness logic in domain objects
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copied!<p>I am coding a ribbon/achievements system for a website and I have to write some logic for each ribbon in my system. For example, you could earn a ribbon if you're in the first 2,000 people registering to the website or after 1,000 post in the forum. The idea is very similar to stackoverflow's badges, really.</p> <p>So, every ribbon is obviously in the database but they also need a bit of logic to determine when a user has earned the ribbon.</p> <p>In the way I coded it, <code>Ribbon</code> is a simple interface:</p> <pre><code>public interface Ribbon { public void setId(int id); public int getId(); public String getTitle(); public void setTitle(String title); public boolean isEarned(User user); } </code></pre> <p><code>RibbonJpa</code> is an abstract class that implements the <code>Ribbon</code> interface, avoiding the definition of the <code>isEarned()</code> method:</p> <pre><code>@Entity @Table(name = "ribbon") @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name = "ribbon_type") public abstract class RibbonJpa implements Ribbon { @Id @Column(name = "id", nullable = false) int id; @Column(name = "title", nullable = false) private String title; @Override public int getId() { return id; } @Override public void setId(int id) { this.id= id; } @Override public String getTitle() { return title; } @Override public void setTitle(String title) { this.title = title; } } </code></pre> <p>You can see I define the inheritance strategy as <code>SINGLE_TABLE</code> (since I have to code like 50 ribbons and I don't need additional columns for any of them).</p> <p>Now, a specific ribbon will be implemented like this:</p> <pre><code>@Entity public class FirstUsersRibbon extends RibbonJpa implements Ribbon { public FirstUsersRibbon() { super.setId(1); super.setTitle("First 2,000 users registered to the website"); } @Override public boolean isEarned(User user) { // My logic to check whether the specified user has won the award } } </code></pre> <p>This code works fine, the tables are created in the database in the way I expect (I use DDL generation in my local environment).</p> <p>The thing is, it feels wrong to code business logic in a domain object. Is it good practice? Can you suggest a better solution? Also, I'm not able to Autowire any DAOs in the entity (<code>FirstUsersRibbon</code>) and I need them in the business logic (in this case, I need a DAO to check whether the user is in the first 2,000 users registered to the website).</p> <p>Any help very appreciated.</p> <p>Thank you!</p>

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