iterate an object in struts-2

[Pradeep Adibatla]

I have an ArrayList in a javaclass and I want to iterate that in jsp...

How to achieve this?

The arrayList should be in the action class related to that jsp,isn't it,for the framework to to iterate the arrayList?

[Tudor Raneti]

This should do: Iterator
This should help: struts-2-ognl-expression-language-example-1

try (untested):

  <s:iterator var="counter" begin="1" end='<s:property value="sampleList.size"/>' >
   <!-- current iteration value (1, ... n) -->
   <s:property value="top" />
</s:iterator>
  

unsure how you actually extract the counter variable and index the list, OGNL must be it though.
The Iterator link gives you a hint on some OGNL magic:

  <s:iterator value="days">
  <p>day is: <s:property/></p>
</s:iterator>
  

Let me know if it worked.

[Pradeep Adibatla]

Now this is what I have...

    

 private ArrayList<RuleSet> rses=new ArrayList<RuleSet>();

while (rs1.next())
		    {
		    	String rsId=rs1.getString("RuleSetId");
		    	String rsCat=rs1.getString("RuleSetCategory");
		    	String rsName=rs1.getString("RuleSetName");
		    	String rsDesc=rs1.getString("RuleSetDescription");
		    	String rsAuthor=rs1.getString("RuleSetAuthor");
                String rsFrom=rs1.getString("RSFromDate");
                String rsTo=rs1.getString("RSToDate");

                ruleSet.setRsId(Integer.parseInt(rsId));
                ruleSet.setCategory(rsCat);
                ruleSet.setRulesetName(rsName);
                ruleSet.setDescripion(rsDesc);
                ruleSet.setAuthor(rsAuthor);
                ruleSet.setFromDate(rsFrom);
                ruleSet.setToDate(rsTo);
                
                rses.add(ruleSet);

    }

SO my Iterator will look like this...

 

<s:iterator value="rses" status="pos">
                <tr onclick="select(this)" >
                   <s:iterator value="rses[#pos.count]" status="pos">
                   <td ><s:property value=???></td>
                </tr>
                </s:iterator>

   

???--- there should be a td for each element of the bean? how is that achieved ?

[Ankit Garg]

Pradeep, first of all you've shown us incomplete code, your code has two starting iterator tags but only one of them is closed.

Actually the second iterator is not needed, you just need the var attribute of iterator tag. The iterator needs to iterate over the ArrayList and inside that, you need to put multiple <td> elements with s:property tags within it. Something like this

<s:iterator value="rses" status="pos" var="res">
  <tr>
    <td><s:property value="res.rsId" /></td>
    <td><s:property value="res.category" /></td>
    <td><s:property value="res.rulesetName" /></td>
  </tr>
</s:iterator>

[David Newton]

Tudor Andrei Raneti wrote:

  <s:iterator var="counter" begin="1" end='<s:property value="sampleList.size"/>' >

That's not legal JSP...

[Tudor Raneti]

Yea, Eclipse sais about end and begin attributes that they are undefined.
I copy pasted the example from struts-2 documentation (since he asked for struts 2 as he sais in title):
http://struts.apache.org/2.1.8.1/docs/iterator.html
and only added the <s:property tag

A loop that iterates 5 times

  <s:iterator var="counter" begin="1" end="5" >
   <!-- current iteration value (1, ... 5) -->
   <s:property value="top" />
</s:iterator>
  

That's why i also said "try (untested):". Is struts 2 documentation missleading?

my result was on using that: Attribute begin invalid for tag iterator according to TLD
Anyway it would've been nice to see it work like that...

[David Newton]

There's no nested JSP tags in the examples. The begin/end attributes were added sometime around 2.1.6 or so (I don't recall for sure). If you're not using a version that includes those attributes it won't work.

[Tudor Raneti]

I'm using struts 2.1.8.1 (which is the latest)
And this is the struts 2 documentation alright:

libraries in eclipse:

They still don't work...

[Pradeep Adibatla]

I am using Struts 2.0.11 and, there is no thing as 'var',so I presume it as; id='res'.

Now, I write like this

<s:iterator value="rses" status="pos" id="res">
<tr>
<td><s:property value="res.rsId" /></td>
<td><s:property value="res.category" /></td>
<td><s:property value="res.rulesetName" /></td>
<td><s:property value="res.descripion" /></td>
<td><s:property value="res.author" /></td>
<td><s:property value="res.fromDate" /></td>
<td><s:property value="res.toDate" /></td>
<td><s:property value="res.rsPid" /></td>
</tr>
</s:iterator>


but it doesn't display the records... is id incorrect?

[Ankit Garg]

Are you sure there are records in your database?? And since rses is private in your action, do you have public getter/setter methods for rses property in your action??

[Pradeep Adibatla]

Is it compulsary to have the ArrayLists only in the Action ? can't I have them in any class?
Will the framework look for the Arraylist name present in the Iterator only in Action class and not in other classes?
I have my 'rses' in the class that is taking data from DB and if the aforementioned is true then no wonder I don't see any records!

[Ankit Garg]

Is it compulsary to have the ArrayLists only in the Action ? can't I have them in any class?

What do you mean by "any class". Struts only accesses properties of your action class. Action class doesn't necessarily mean sub-class of ActionSupport, it can be any POJO which is declared as a action in the struts.xml config file. So basically if rses is a property of your action which is serving the request, then the iterator will work. If you want to manually put rses as an attribute in any scope, then you can use the #<scope> syntax of OGNL...

[Pradeep Adibatla]

Now it's very clear but still not populating values though...

yes there is data in DB and the get,set are public!

Wonder what else could be the culprit!

Also I tried in a seperate file like this... on success directed to this jsp

  

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1>Hello World!</h1>
        <s:iterator value="rsList" status="pos" id="res">
                  <h4><s:property value="res.rsId" /></h4>
                  <h4><s:property value="res.category" /></h4>
                  <h4><s:property value="res.rulesetName" /></h4>
                  <h4><s:property value="res.descripion" /></h4>
                  <h4><s:property value="res.author" /></h4>
                  <h4><s:property value="res.fromDate" /></h4>
                  <h4><s:property value="res.toDate" /></h4>
       </s:iterator>   
 </body>
</html>

  

It doesn't print anything! how to track this?

[Ankit Garg]

What is the actual name of the property in your action?? Is it rses or rsList?? Put a log or System.out.println statement in your while loop to see if the list actually contains elements i.e. whatever the query you use to get results from the database, actually return any value or not...

[Pradeep Adibatla]

it is rsList and its properly displaying the values ...

Here it is ...

  

while (rs1.next())
		    {
		    	String rsId=rs1.getString("RuleSetId");
		    	String rsCat=rs1.getString("RuleSetCategory");
		    	String rsName=rs1.getString("RuleSetName");
		    	String rsDesc=rs1.getString("RuleSetDescription");
		    	String rsAuthor=rs1.getString("RuleSetAuthor");
                String rsFrom=rs1.getString("RSFromDate");
                String rsTo=rs1.getString("RSToDate");
                String rspid=rs1.getString("ProjId");


                System.out.println("------------------------------------------------------------");
                System.out.println("The rsIS is :--> "+rsId);
                System.out.println("The rsCat is :--> "+rsCat);
                System.out.println("The rsName is :--> "+rsName);
                System.out.println("The rsDesc is :--> "+rsDesc);
                System.out.println("The rsAuthor is :--> "+rsAuthor);
                System.out.println("The rsFrom is :--> "+rsFrom);
                System.out.println("The rsTo is :--> "+rsTo);
                System.out.println("The rspid is :--> "+rspid);
                System.out.println("-------------------------------------------------------------");

                ruleSet.setRsId(Integer.parseInt(rsId));
                ruleSet.setCategory(rsCat);
                ruleSet.setRulesetName(rsName);
                ruleSet.setDescripion(rsDesc);
                ruleSet.setAuthor(rsAuthor);
                ruleSet.setFromDate(rsFrom);
                ruleSet.setToDate(rsTo);
                ruleSet.setRsPid(Integer.parseInt(rspid));
                
                rses.add(ruleSet);

                System.out.println("------------  ONE RULESET OBJECT ADDED ---------");

              

		    	i++;
		    }

            System.out.println("The rses size is :--> "+rses.size());

  

Here's the output... There is only 1 record in DB...

------------------------------------------------------------
The rsIS is :--> 1
The rsCat is :--> wef
The rsName is :--> Rs1
The rsDesc is :--> rg
The rsAuthor is :--> 3r5g
The rsFrom is :--> 2009-12-14
The rsTo is :--> 2009-12-28
The rspid is :--> 1
-------------------------------------------------------------
------------ ONE RULESET OBJECT ADDED ---------
The rses size is :--> 1




The while loop is in method getRSDataForProject() residing in a seperate class... This method is called from the action class as shown below!

In the action class...

    

ArrayList rsList;

    public ArrayList getRsList() {
        return rsList;
    }

   
  private DBToRuleSetPersistence dbtrsp;

                 ....


                 dbtrsp=new DBToRuleSetPersistence();
                 rsList=new ArrayList();

                ....

                  dbtrsp.getRSDataForProject();
                  rsList=DBToRuleSetPersistence.getRses();

                  System.out.println(" ----> size of rsList is :--> "+rsList.size());
                  target= "success2";

output:-

----> size of rsList is :--> 1

I hope the Iterator is fine!

[Ankit Garg]

The while loop is in method getRSDataForProject() residing in a seperate class

So basically getRSDataForProject method is in DBToRuleSetPersistence class?? Does this method return the ArrayList or not?? As I can see, there seems to be a getRses method in the DBToRuleSetPersistence class which actually returns the ArrayList. So does the getRSDataForProject method actually sets the ArrayList to a static field which is returned by the getRses method?? If that's the case then this might create concurrency problems. Other than that there doesn't seem to be any problem with the code. The iterator should work...

[Tudor Raneti]

If nothing works, <c:foreach> is there.

[Pradeep Adibatla]

No,that method does not return anything!


This is the rses ArrayList in DBToRuleSetPersistence class.

   

private ArrayList<RuleSet> rses=new ArrayList<RuleSet>();

    public ArrayList<RuleSet> getRses() {
        return rses;
    }

    public void setRses(ArrayList<RuleSet> rses) {
        this.rses = rses;
    }

 

but in action class the ArrayList is

  
ArrayList rsList;   
  
    public ArrayList getRsList() {   
        return rsList;   
    }   


  

is there a problem??

I can see that it's adding the row( very much compressed than usual size) but nothing in it!

[Ankit Garg]

I have no clue how your code is working. In the code that you showed, getRses is an instance method. But in the previous code, you called getRses as if it were a static method (21. DBToRuleSetPersistence.getRses()). I don't even know what this line means

I can see that it's adding the row( very much compressed than usual size) but nothing in it!

Adding the row where?? Print the values in the ArrayList in your action class i.e. after you call rsList=DBToRuleSetPersistence.getRses(); to see if there are actually any elements in the list. Also when your JSP is executed, see if there's any exception that is coming (although there's no reason for an exception, still there's no harm in checking)...

[Pradeep Adibatla]

Adding the row, meaning I am iterating a <TR> and I could see a small,compressed row adding to the header of table...

yeah the values in rsList are fine..here it is...

  


for (Iterator<Object> it = rsList.iterator(); it.hasNext();)
                   {
                       RuleSet ob = (RuleSet) it.next();

                       System.out.println("The 1 is :--> "+ob.getRsId());
                       System.out.println("The 2 is :--> "+ob.getCategory());
                       System.out.println("The 3 is :--> "+ob.getRulesetName());
                       System.out.println("The 4 is :--> "+ob.getDescripion());
                       System.out.println("The 5 is :--> "+ob.getAuthor());
                       System.out.println("The 6 is :--> "+ob.getFromDate());
                       System.out.println("The 7 is :--> "+ob.getToDate());
                       System.out.println("The 8 is :--> "+ob.getRsPid());


                   }



  

output:-
---------


The 1 is :--> 1
The 2 is :--> wef
The 3 is :--> Rs1
The 4 is :--> rg
The 5 is :--> 3r5g
The 6 is :--> 2009-12-14
The 7 is :--> 2009-12-28
The 8 is :--> 1


Still I see no values...

This is frustratimg!

[David Newton]

Try using a "#" character in the OGNL inside the iterator, so if the "id" attribute is "res", use "#res.theProperty" in the property tags (where "theProperty" is a property of the object). Alternatively, you can just use "theProperty" by itself, since each object will be put on the top of the stack.

[Pradeep Adibatla]

yep the '#' works.i think OGNL is complete with a '#'


Thanks Ankit,David and co...

[Maki Jav]

The Action class should have getter and setters for the list

ie

 private ArrayList<RuleSet> rsList=new ArrayList<RuleSet>();  
   
     public ArrayList<RuleSet> getRsList() {  
         return rsList;  
     }  
   
     public void setRsList(ArrayList<RuleSet> rses) {  
         this.rsList = rses;  
     }  

In the jsp you need to do the following...

No need to use a prefix of list name for each property...


<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<h1>Hello World!</h1>
<s:iterator value="rsList" status="pos" id="res">
<h4><s:property value="rsId" /></h4>
<h4><s:property value="category" /></h4>
<h4><s:property value="rulesetName" /></h4>
<h4><s:property value="descripion" /></h4>
<h4><s:property value="author" /></h4>
<h4><s:property value="fromDate" /></h4>
<h4><s:property value="toDate" /></h4>
</s:iterator>
</body>
</html>


Hope it is helpful to you...

Maki Jav

[Pradeep Adibatla]

Yep! As david said eother with hash or directly the variablename of the object... thanks!