JSF: how to update the list after delete an item of that list
- by Harry Pham
It will take a moment for me to explain this, so please stay with me. I have table COMMENT that has OneToMany relationship with itself.
@Entity
public class Comment(){
...
@ManyToOne(optional=true, fetch=FetchType.LAZY)
@JoinColumn(name="REPLYTO_ID")
private Comment replyTo;
@OneToMany(mappedBy="replyTo", cascade=CascadeType.ALL)
private List<Comment> replies = new ArrayList<Comment>();
public void addReply(NewsFeed reply){
replies.add(reply);
reply.setReplyTo(this);
}
public void removeReply(NewsFeed reply){
replies.remove(reply);
}
}
So you can think like this. Each comment can have a List of replies which are also type Comment. Now it is very easy for me to delete the original comment and get the updated list back. All I need to do after delete is this.
allComments = myEJB.getAllComments(); //This will query the db and return updated list
But I am having problem when trying to delete replies and getting the updated list back. So here is how I delete the replies. Inside my managed bean I have
//Before invoke this method, I have the value of originalFeed, and deletedFeed set.
//These original comments 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 comment 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();
}
}
Then inside my EJB scholarEJB, I have
public void removeReply(NewsFeed comment, NewsFeed reply){
comment = em.merge(comment);
comment.removeReply(reply);
em.persist(comment);
}
public void deleteFeeds(NewsFeed e){
e = em.find(NewsFeed.class, e.getId());
em.remove(e);
}
When I get out, the entity (the reply) get correctly removed from the database, but inside the feeds List, reference of that reply still there. It only until I log out and log back in that the reply disappear. Please help
