iterate object

[lynn fann]

how do i do <logic:iterate>? my code as below. what are the things that i have to add/change. Im using hibernate and struts. thanks

Actionclass:

  
 List lMessage= msgr.getMessages(sThreadId);        
       
        for(int i=0; i<lMessage.size();i++)
        {
          MessageForm oForm = (MessageForm) form;
          msgObj = (Message) lMessage.get(i);     
          oForm.setThreadId(msgObj.getThreadId());
}
  

what should i do so that in my jsp page, i can <logic:iterate> and <bean:write>

[sreenivas jeenor]

Hi,

put down your lMessage i.e List object in request/session scope in action class and use in the following way in the jsp page

<logic resent name="lMessage " scope="request">
<bean:size id="mcount" name="lMessage "/>

<logic:greaterThan name="mcount" value="0">
<logic:iterate id="msgs" name="lMessage ">

<bean:write name="msgs" property="Message"/>
</logic:iterate>
</logic:greaterThan>
</logic resent>

hope this will work for you.

[lynn fann]

hi,
after amendent my code is *in bold are added lines:

action class

 
List lMessage= msgr.getMessages(sThreadId);        
        for(int i=0; i<lMessage.size();i++)
        {
          MessageForm oForm = (MessageForm) form;
          msgObj = (Message) lMessage.get(i);     
          oForm.setThreadId(msgObj.getThreadId());   
        }      
       [B]request.setAttribute("lMessage",lMessage);[/B]
   

service class

 public static List getMessages(String threadId)
    {
       String sSql="from Message where THREAD_ID="+threadId;
        List lMessage = HibernateAction.search(sSql);
     return lMessage;
    }

hibernate class

 
 public static List search(String sQuery) throws HibernateException{
        final String _METHOD = "[search] ";
        try {
            session = HibernateUtils.openSession();
            List lResult = session.createQuery(sQuery).list();
            HibernateUtils.flushSession();
            log.debug(_METHOD + sQuery + "=" + lResult);
            return lResult;
        } catch (HibernateException e) {
            log.error(_METHOD + e);
            throw e;
        } finally {
            if (session!=null)
                HibernateUtils.closeSession();
        }
    }
   

in jsp:

   
        <logic :-P	 resent name="lMessage" scope="request">
<bean:size id="mcount" name="lMessage"/>
 
<logic:greaterThan name="mcount" value="0">
<logic:iterate id="msgs" name="lMessage">
 
<bean:write name="msgs" property="Message"/>
</logic:iterate>
</logic:greaterThan>
</logic :-P	 resent>     
    </td>
 

however, i get a blank page. what went wrong. Should i setAttribute for lMessage or msgObj

[sreenivas jeenor]

I dont have idea about hibernate..

anyway checkout lMessage size in action class..if the size is greater than 0,the given code will be working

place this code after </logic:greaterThan> tag


<logic:equal name="msg" value="0">
print here saying value is 0
</logic:equal>

if you get message saying 0,then your list size is 0.

[Merrill Higginson]

First of all, the for loop in your action class is useless. All you're doing is setting the same property in the form bean over and over again.

Secondly, all you need in your JSP is this:

<logic:iterate id="msgs" name="lMessage" >
  <bean:write name="msgs" />
</logic:iterate>

Everything else is unnecessary. If it doesn't display anything, it's because your List of messages is empty.

[lynn fann]

what could cause the list to return null? is it my database mapping or what? i get my message as null

[Merrill Higginson]

I suspect it's the Hibernate query that's not returning anything. Are you sure the database table actually has rows? Are you sure your hibernate query is valid? Is THREAD_ID a string? if so, append single quotes around the id. Having a property named THREAD_ID is very non-standard. Are you sure that's the right property name for your Hibernate POJO?

[lynn fann]

i have tried this:
String sql="from Message";
lMessage = HibernateAction.search(sql);

my pojo is name as Message.java

when i print out the lMessage, it is [null,null]. im able get the size of the list which is 2 in this case. what went wrong?