Stripes: prepopulated forms question

[Gabriele Fabbri]

Hi all,

Stripes Framework 1.5

I'm getting a little problem trying populating a form with data retrieved from the database (MySQL).
I have implemented the Stipersist library and Hibernate, and I'm able to insert new data in db and read list of records, but I can't understand how to populate form fields for the update function: I'm getting an empty form, but if write some data and submit the record is updated correctly (so, it works).

I'm problably doing something wrong passing the paramenter from the list to the edit form...

Some code.

news_list.jsp

...
<s:link beanclass="prj.action.NewsViewActionBean" event="edit">
<s:param name="news" value="${news}"/>
Modify
</s:link>
...

This link pass the news=IdNumber parameter, as explained in the Stripes book, to the action bean.
The action bean, on the edit event, simply forward to news_edit.jsp.

news_edit.jsp

<s:form beanclass="prj.action.NewsEditActionBean">
<s:hidden name="news"/>
<s:text name="news.title"/>
<s:text name="news.text"/>
<s:submit name="save" value="send"/>
</s:form>

This code is working properly, but form fields are not filled.

I also tried using:

<s:text name="news.title" value="${news.title}"/>

... but I'm still getting empty fields.

Any idea?
Thanks.

[Frederic Daoud]

Hi Gabriele,

Could you also post the code for NewsViewActionBean and NewsEditActionBean?

That will help find the cause of the problem.

Cheers,

[Gabriele Fabbri]

Hi Frederic,
it's nice to meet the author of the book I'm reading!

NewsViewActionBean

public class NewsViewActionBean extends NewsBaseActionBean {

    /* PROPERTIES */

    private static final String LIST = "/news_list.jsp";
    private static final String EDIT = "/news_edit.jsp";
    
    private List<News> newsList;
    private News news;

    public List<News> getNewsList() {
        return newsList;
    }
    public void setNewsList(List<News> newsList) {
        this.newsList = newsList;
    }

    /* METHODS */

    @Override
    public void setNews(News news) {
        super.setNews(news);
    }

    @DefaultHandler
    public Resolution compose() {
        return new ForwardResolution(EDIT);
    }

    public Resolution list() {
        newsList = newsDao.read();
        return new ForwardResolution(LIST);
    }
    
    public Resolution edit() {
        return new ForwardResolution(EDIT);
    }
}

NewsEditActionBean

public class NewsEditActionBean extends NewsBaseActionBean {

    /* PROPERTIES */

    private static final String INDEX = "/index.jsp";

    private News news;


    /* HANDLERS */

    @Override
    public void setNews(News news) {
        super.setNews(news);
    }

    @DefaultHandler
    public Resolution save() {
        news = getNews();
        newsDao.save(news);
        newsDao.commit();
        return new RedirectResolution(INDEX);
    }
}

[Frederic Daoud]

Gabriele Fabbri wrote:
it's nice to meet the author of the book I'm reading!

I hope you are enjoying the book!

Do you have a getter method for News in NewsBaseActionBean? As in

public News getNews() {
  return news;
}

Otherwise the JSP will not be able to obtain the News object and prepopulate your form with <s:text name="news.title"/>.

As a side note, is there a particular reason why you are doing this in NewsViewActionBean and NewsEditActionBean?

@Override  
public void setNews(News news) {  
  super.setNews(news);  
}

As they are now, both methods are redundant and could be removed.

Let me know if you are still having problems.

Cheers,

[Gabriele Fabbri]

Thank you for the fast reply Frederic.
Yes, your book is absolutely one of the most useful books I have read in 2008!

This is the code of the NewsBaseActionBean

public abstract class NewsBaseActionBean extends BaseActionBean {
    
    private News news;

    public News getNews() {
        return news;
    }
    public void setNews(News news) {
        this.news = news;
    }
}

I tried removing the @Override of the getNews method, as you suggested (I don't remember why I put it there...), but I'm still getting empty fields.

[Frederic Daoud]

Thank you for your kind words, Gabriele!

I've reviewed your code and compared it with the sample code from the Stripes book. The only thing I can think of at the moment is that perhaps the value of ${news} is not being set in:

<s:param name="news" value="${news}"/>

Could you post the complete code from news_list.jsp?

Cheers,

[Gabriele Fabbri]

Of course!

This is the code of the news_list.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="s" uri="http://stripes.sourceforge.net/stripes.tld"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>News List</title>
    </head>
    <body>
        <h1>News List</h1>
        <c:forEach items="${actionBean.newsList}" var="news" varStatus="rowstat">
            Title: ${news.titolo}
            <s:link beanclass="jpa.action.NewsViewActionBean" event="edit">
                <s:param name="news" value="${news}"/>
                Modifica
            </s:link>
            <s:link beanclass="jpa.action.NewsEditActionBean">Elimina</s:link>
            <br/>
        </c:forEach>
    </body>
</html>

Following the link "Modifica" (modify) the generated url is
http://localhost:8080/jpa/NewsView.action?edit=&news=6

If I understood, "6" correspond to the ID property of the News entity (obtained by the Stripersist TypeConverter), and it seems to work fine, because if I submit the Edit form I'm able to UPDATE the correct record.

Just to be sure, I would ask you a little clarification: in chapter 3 (page 54) you explain how to get a prepopulated form by submitting directly the ID of the object from the list page to the edit form. In this way I can get filled form fields, but in chapter 12 you say that, using Stripersist and Hibernate, it is possibly to submit the entity News as parameter of the link (as I'm doing now).
My doubt is if I have now to write form fields like <s:text name="news.titolo"/> or <s:text name="news.titolo" value="${news.titolo}"/> in the edit form.

Just a note: please forget differences on properties names between code in previous posts and this, I can ensure you that they are consistant

Thank you.

[Frederic Daoud]

Gabriele,

So far, I don't see any problem with the source code that you have posted. I have a feeling that it is just a small detail somewhere that is preventing the form from being prepopulated. It should work as you have described.

If you can create a zip file of the source code for your example and email it to me so that I can reproduce the problem, I'll try to find what is missing.

Cheers,

[Gabriele Fabbri]

Thank you Frederic for your attention, I really apreciate this.
I'll try to solve the issue tomorrow, in case I wont be able to find the solution by my self, I will send you the zipped source.

Regards,
Gabriele

[Gregg Bolinger]

So here is what I noticed. The edit method doesn't do anything but forward to a view. My first question is, does the type converter that Stripersist creates automatically populate the object from the database or should that be done in the edit method of the action bean?

[Frederic Daoud]

Gregg Bolinger wrote:So here is what I noticed. The edit method doesn't do anything but forward to a view. My first question is, does the type converter that Stripersist creates automatically populate the object from the database or should that be done in the edit method of the action bean?

If the class is annotated with JPA annotations (@Entity, @Id), the Stripersist type converter automatically populates the object.

I was going to ask Gabriele to post the code for the News class, but I figured that it was properly annotated since the update does work and the correct changes are made to the database.

[Gregg Bolinger]

Frederic Daoud wrote:

Gregg Bolinger wrote:So here is what I noticed. The edit method doesn't do anything but forward to a view. My first question is, does the type converter that Stripersist creates automatically populate the object from the database or should that be done in the edit method of the action bean?

If the class is annotated with JPA annotations (@Entity, @Id), the Stripersist type converter automatically populates the object.

I was going to ask Gabriele to post the code for the News class, but I figured that it was properly annotated since the update does work and the correct changes are made to the database.

[OFFTOPIC] This is scary because you have no control over it happening or not. One of a handful of reasons I'm not a big fan of Stripersist.[/OFFTOPIC]

That's what I thought but wanted to make sure I was correct. What I would do then is set a breakpoint in the edit method and look at the news property and see if it is populated and for whatever reason just not making it to the JSP. But other than that, I agree with Freddy that everything looks normal.

[Frederic Daoud]

Hi Gabriele,

I finally found the problem: the link to edit the News item targets NewsListActionBean, but it should target NewsEditActionBean since this is the bean used in news_edit.jsp, in the <s:form beanclass=""> tag. Otherwise, Stripes does not find the News object, and that is why the form was always blank.

Here is the code to be changed:

news_list.jsp:

<s:link beanclass="jpa.action.NewsEditActionBean">
  <s:param name="news" value="${news}"/>
   Modifica
</s:link>

NewsEditActionBean.java:

private static final String EDIT = "/news_edit.jsp";

@DefaultHandler
public Resolution edit() {
    return new ForwardResolution(EDIT);
}

public Resolution save() {
    // same as before
}

The news_edit.jsp does not need any changes, and now displays a prepopulated form.

Cheers,

[Gabriele Fabbri]

I confirm that it works perfectly.
Thank you very much Frederic to share you knowledge in a friendly way!

Cheers,