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vector
 Post subject: not able to update many-to-many relationship
PostPosted: Fri Oct 23, 2009 6:21 am 
Beginner
Beginner

Joined: Mon May 26, 2008 3:34 am
Posts: 31
Hello everyone,

I have two classes Article and Tag. An article can have a list of tags and a tag can be present in any article. I will show the relevant part of the code.
Article.java
Code:
public class Article implements Serializable, Auditable {
        ......
   private List<Tag> tagList = null;
        ......
}

Tag.java
Code:
public class Article implements Serializable, Auditable {
        ......
   private int id = 0;
   private String keyword = null;
   private int count = 0;
   private Timestamp creationDate = new Timestamp(new Date().getTime());
   private List<Article> articleList = null;
        ......
}


And here is the mapping files:
Article.hbm.xml
Code:
....
<bag name="tagList" table="article_tag" cascade="all">
      <key column="id_article" not-null="true"/>
      <many-to-many column="id_tag" class="com.model.metadata.Tag"/>
    </bag>
....


Tag.hbm.xml
Code:
....
<bag name="articleList" table="article_tag" cascade="all" inverse="true">
      <key column="id_tag" not-null="true"/>
      <many-to-many column="id_article" class="com.model.article.Article"/>
    </bag>
....


And this is the part of my code where i get the article data related to tags and insert/update my article
Code:
.....
List<Article> articleList = new ArrayList<Article>();   
         tagValues = StringUtils.split(value, " ");
         for (int i = 0; i < tagValues.length; i++) {
            this.tag = new Tag();
            this.tag.setKeyword(tagValues[i]);
            this.tag.setArticleList(articleList);
            this.tagList.add(this.tag);
         }
......
this.article.setTagList(this.tagList);
......


When i insert a new article with new tags everything works fine, the problem is when i try to update the article, my code does not update the existing tags, it inserts them again.

Any idea of what could be wrong?

Thanks a lot in advance.
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vector
 Post subject: Re: not able to update many-to-many relationship
PostPosted: Mon Oct 26, 2009 6:06 am 
Beginner
Beginner

Joined: Mon May 26, 2008 3:34 am
Posts: 31
Any help on this? i am still stuck on this and not able to find a solution.

Thanks a lot in advance
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pretham
 Post subject: Re: not able to update many-to-many relationship
PostPosted: Mon Oct 26, 2009 10:25 am 
Beginner
Beginner

Joined: Mon Sep 14, 2009 9:29 am
Posts: 30
I think the object which u r updating is detached ...The solution to this prob can be using session.load(primarykey column)...
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vector
 Post subject: Re: not able to update many-to-many relationship
PostPosted: Tue Oct 27, 2009 2:35 pm 
Beginner
Beginner

Joined: Mon May 26, 2008 3:34 am
Posts: 31
Thanks for the response pretham, but that did not solve my problem.

I have tried to modify the part of my code where i get the article data related to tags and insert/update my article
Code:
tagValues = StringUtils.split(value, " ");
         for (int i = 0; i < tagValues.length; i++) {
            this.tag = new Tag();
            this.tag.setKeyword(StringUtils.trim(tagValues[i], " "));            
            if(this.article.getTagList() != null) {
               this.article.getTagList().add(this.tag);
            } else {
               this.article.setTagList(new ArrayList<Tag>());
               this.article.getTagList().add(this.tag);
            }
            if(this.tag.getArticleList() != null) {
               this.tag.getArticleList().add(this.article);
            } else {
               this.tag.setArticleList(new ArrayList<Article>());
               this.tag.getArticleList().add(this.article);
            }
         }


But it did not work either, any other idea?

Thanks again
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vector
 Post subject: Re: not able to update many-to-many relationship
PostPosted: Mon Nov 02, 2009 3:38 pm 
Beginner
Beginner

Joined: Mon May 26, 2008 3:34 am
Posts: 31
Hi again,

I was not be able to make it work.

Do i have to do this everytime i need to update my collection?
Code:
// if it does no exist in actual list i add it
         tagValues = StringUtils.split(value, " ");
         Tag object = null;
         boolean exist = false;
         for (int i = 0; i < tagValues.length; i++) {
            this.tag = new Tag();
            this.tag.setKeyword(StringUtils.trim(tagValues[i], " "));
            if(this.article.getTagList() != null) {
               for (Iterator iterator = article.getTagList().iterator(); iterator.hasNext();) {
                  object = (Tag) iterator.next();                  
                  if(object.getKeyword().equals(this.tag.getKeyword()))
                     exist = true;               
               }
            } else {
               this.article.setTagList(new ArrayList<Tag>());
            }
            if(!exist)
               this.article.getTagList().add(tag);
            exist = false;
         }
         // if it does not exist in the new list i remove it
         exist = false;         
         if(this.article.getTagList() != null) {
            for (Iterator iter = article.getTagList().iterator(); iter.hasNext();) {
               object = (Tag) iter.next();
               System.out.println(object.getId() + " - " + object.getKeyword());
               for (int i = 0; i < tagValues.length; i++) {               
                  this.tag = new Tag();
                  this.tag.setKeyword(StringUtils.trim(tagValues[i], " "));
                  
                  if(this.tag.getKeyword().equals(object.getKeyword()))
                     exist = true;                  
               }
               if(!exist) {                  
                  iter.remove();
                  object.setArticleList(null);
                  TagDAO tagDao = new TagDAO();
                  tagDao.makeTransient(object);
               }                  
               exist = false;
            }
         } else {
            this.article.setTagList(new ArrayList<Tag>());
         }


Please, is there any other solution to my issue?

Thanks again
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