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POHow to update the list after delete an item of that list
 

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  1. POHow to update the list after delete an item of that list
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    <p>It will take a moment for me to explain this, so please stay with me. I have table <code>NewsFeed</code> that has OneToMany relationship with itself. </p> <pre><code>@Entity public class NewsFeed(){ ... @ManyToOne(optional=true, fetch=FetchType.LAZY) @JoinColumn(name="REPLYTO_ID") private NewsFeed replyTo; @OneToMany(mappedBy="replyTo", cascade=CascadeType.ALL) private List&lt;NewsFeed&gt; replies = new ArrayList&lt;NewsFeed&gt;(); public void addReply(NewsFeed reply){ replies.add(reply); reply.setReplyTo(this); } public void removeReply(NewsFeed reply){ replies.remove(reply); } } </code></pre> <p>So you can think like this. Each feed can have a <code>List</code> of replies which are also type <code>NewsFeed</code>. Now it is very easy for me to delete the original feed and get the updated list back. All I need to do after delete is this. </p> <pre><code>feeds = scholarEJB.findAllFeed(); //This will query the db and return updated list </code></pre> <p>But I am having problem when trying to delete <code>replies</code> and getting the updated list back. So here is how I delete the <code>replies</code>. Inside my JSF managed bean I have</p> <pre><code>//Before invoke this method, I have the value of originalFeed, and deletedFeed set. //These original feeds are display inside a p:dataTable X, and the replies are //displayed inside p:dataTable Y which is inside X. So when I click the delete button //I know which feed I want to delete, and if it is the replies, I will know //which one is its original post public void deleteFeed(){ if(this.deletedFeed != null){ scholarEJB.deleteFeeds(this.deletedFeed); if(this.originalFeed != null){ //Since the originalFeed is not null, this is the `replies` //that I want to delete scholarEJB.removeReply(this.originalFeed, this.deletedFeed); } feeds = scholarEJB.findAllFeed(); } } </code></pre> <p>Then inside my EJB scholarEJB, I have </p> <pre><code>public void removeReply(NewsFeed feed, NewsFeed reply){ feed = em.merge(feed); comment.removeReply(reply); em.persist(comment); } public void deleteFeeds(NewsFeed e){ e = em.find(NewsFeed.class, e.getId()); em.remove(e); em.getEntityManagerFactory().getCache().evict(NewsFeed.class); //Like fdreger suggested } </code></pre> <p>When I get out, the entity (the reply) get correctly removed from the database, but inside the <code>feeds</code> List, reference of that <code>reply</code> still there. It only until I log out and log back in that the reply disappear.</p>
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