Equivalent of logic iterate in Struts 2

[Vic Hood]

Hi.
Im currently working on migrating an application from Struts 1.x to Struts 2 , and have been trying to figure out an equivalent to logic iterate , as im using html indexed fields using an iterator .
Currently ,
its in the form --

<logic:iterate id="listDetails" name="list" scope="session" type="com.enzen.domain.vo.DomainDetailsVO" >
<tr>
<td><bean:write name="listDetails" property="code"/></td>
<td><bean:write name="listDetails" property="description"/></td>
<td><bean:write name="listDetails" property="active"/></td>
<td><bean:write name="listDetails" property="edit"/></td>



</tr>
</logic:iterate>

It would be great if anyone could help in how to implement the same using struts 2 tags or a workaround..


Thanks in Advance .

[Tom Rispoli]

you'll probaly want to use s:iterator to do the loop and s:property to display your data.

something like this:

<s:iterator value="list" status="listStatus">
    <s:property value="code"/>
    <s:property value="description"/>
    <s:property value="active"/>
    <s:property value="edit"/>
</s:iterator>

s:iterator will look for "list" in your Ognl value statck, if this is a property of your action class tha you have exposed correctly with getters and setters it will be found on the value stack. As the iterator pulls each element from the list it will put the elment on top of the stack. So when the first s:property tag runs, it will look for "code" on the stack and it should find it in the element from your list that was pushed onto the stack (again, assuming that it is a property of the element with getters and setters). If you want to generate input fields in the loop its a little more complicated, you'll need to give the fully qualified path to the property in your action class and specify what index its at using listStatus.index.

[Vic Hood]

Thanks for the reply tom!

Ill try and implement the same .
I was also looking at whether there was an equivalent for the <logic:notEmpty> tag which checks whether a list or structure is empty before processing a code block.
Right now , im using an if else block of this nature,---

				<s:if test="(list == null || list.equals(''))">
  					<jsp:forward page="interface.jsp">  //</jsp:forward><!-- Not sure , too fantastic! -->(if arraylist  "list" is = null)
				</s:if>
	
	
	// (normal flow of logic)-->)
				<s:else>
 				  			<TABLE class="DocMasterFooterTable" width="75%" border="1">
			<TR>
</s:else> 

[Tom Rispoli]

If you don't want to use the s:else then you could do

<s:if test="list != null && list.size > 0">

[Vic Hood]

Thanks tom!

[Tom Rispoli]

No Problem, hope it helps.

[Vic Hood]

Hi Tom,
Ive been trying to implement your logic and currently dont have any input fields to be generated within the record , in that case how do I use the ---- status="listStatus" part in my code , is it needed or can i do away with it . Please explain its use and relevance .
Thanks.

Tom Rispoli wrote:you'll probaly want to use s:iterator to do the loop and s:property to display your data.

something like this:

<s:iterator value="list" status="listStatus">
    <s:property value="code"/>
    <s:property value="description"/>
    <s:property value="active"/>
    <s:property value="edit"/>
</s:iterator>

s:iterator will look for "list" in your Ognl value statck, if this is a property of your action class tha you have exposed correctly with getters and setters it will be found on the value stack. As the iterator pulls each element from the list it will put the elment on top of the stack. So when the first s:property tag runs, it will look for "code" on the stack and it should find it in the element from your list that was pushed onto the stack (again, assuming that it is a property of the element with getters and setters). If you want to generate input fields in the loop its a little more complicated, you'll need to give the fully qualified path to the property in your action class and specify what index its at using listStatus.index.

[Tom Rispoli]

Hi Vic,

by setting the status attribute you get a reference to an object that has information about the status of the iterator. Amongst the information is the index that the iterator is currently processing. For your puropses (just using s:property in the iterator) you don't really need a reference to this object. However, if you were creating input fields in the iterator and you wanted the names of the input fields to allow struts2 to put them into the same list that they were read from correctly, you need to use the full name of property that you are putting in the input field (rather than just the name to access it from the object that the iterator puts on top of the stack).

So if you wanted to display "code" in an input field that would repopulate your form, the tag would look like this:

<s:textfield name="[list%{#listStatus.index}].code"/>

[Vic Hood]

Hi Tom,

Thanks for the information.
I'm currently not implementing any input fields and I think wouldn't be needing the status parameter.However, I'm currently faced with another difficulty, my screen involves loading a dropdown box whose values are populated from a database. Ive written a method for the same , that returns a List from the database , but when i write the code for the drop down in the jsp , do i call the name of the list OR the action associated with populating the list
ie. JSP

<s:select list="domainList" listKey="bean.objid"  listValue="bean.code"   headerKey="0" headerValue="D.T DropDown " label="DomainType"></s:select>

OR

<s:select list="loadDomainType" listKey="bean.objid"  listValue="bean.code"   headerKey="0" headerValue="D.T DropDown " label="DomainType"></s:select>

Ive also attached snippets of my action class and the dao class to help get a complete idea.

Action

public String loadDomainType(){
		
		String result=SUCCESS;
		try {
			List loadDomainType = DomainDAO.loadDomainType();
			dtList=loadDomainType;
		} catch (Exception e) {
			result=ERROR;
			e.printStackTrace();
		}
		
		
		return result;
	}
	

DAO- Class

public static List loadDomainType() throws Exception {
		Connection con = null;
		PreparedStatement stmt = null;
		ResultSet rs = null;
		DomainBean bean = new DomainBean();
		ArrayList<DomainBean> domainList = new ArrayList<DomainBean>();
		
		try {
			con= DBConnector.getConnection();
			if (con != null){
				System.out.println("Connected");
				String query= " SELECT CODE,DESCRIPTION,OBJECTID FROM DOMAINTYPE " ;
				stmt = con.prepareStatement(query);
				rs = stmt.executeQuery();
				System.out.println("inside loadDomainType");
				while (rs.next()){
					bean.setCode(rs.getString("CODE"));
					bean.setDescription(rs.getString("DESCRIPTION"));
					bean.setObjid(rs.getInt("OBJECTID"));
					domainList.add(bean);
					
				}
				
			}
		} catch (SQLException sqe) {
			sqe.printStackTrace();

		} finally {
			DBConnector.closeResultSet(rs);
			DBConnector.closeStatement(stmt);
			DBConnector.closeConnection(con);
		}

		return domainList;
	}	

Thanks in Advance.

[Vic Hood]

Bounce! Please Help!

[Tom Rispoli]

you want the list attribute to be the name of a property of your action class. So you need to have a variable for it and the getters and setters. In your action clase you'll need to populate the list. Looks like you may have this already, called "dtList". Then you'll want to specify properties of the objects of the list for the "listKey" and "listValue" attributes of the s:select. The property you specify for listValue will be what appears on the screen and what you specify for listKey will be what is returned in the input filed when the form is submitted. So I'd guess you want something more like this:

<s:select list="dtList" listKey="objid"  listValue="code"   headerKey="0" headerValue="D.T DropDown " label="DomainType">

You'll probably also want to specify a name attribute to control what property of your action class the selected value is put into.

[Vic Hood]

Hi Tom
I tried your suggestion . But however it throws the following error.


SEVERE: Servlet.service() for servlet jsp threw exception
tag 'select', field 'list': The requested list key 'dtList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
at org.apache.struts2.components.Component.fieldError(Component.java:231)
at org.apache.struts2.components.Component.findValue(Component.java:293)
at org.apache.struts2.components.ListUIBean.evaluateExtraParams(ListUIBean.java:79)
at org.apache.struts2.components.Select.evaluateExtraParams(Select.java:99)
Please help on how i can correct my code.

[Tom Rispoli]

Hi Vic, looks like your jsp can't find the property "dtList" in the value stack. I saw that variable in the part of your action class that you posted and assumed it was set up as a property with getters and setters. Was this a bad assumption? Is the loadDomainType method in your action class getting called before your JSP is run? Posting more of your action class might help, also are you accessing the JSP by calling a struts action, or are you calling the JSP directly?

[Vic Hood]

Hi Tom,
Im using getters and setters to obtain the "dtList" both in the bean and action class . Im placing the action,bean java classes and the jsp of my project below .Please do have a look.
Thanks for helping.
DomainAction1.java

package com.vivek.struts2.action;

import java.util.ArrayList;
import java.util.List;

import com.opensymphony.xwork2.ActionSupport;
import com.vivek.struts2.*;
import com.vivek.struts2.bean.DomainBean;
import com.vivek.struts2.dao.DomainDAO;

;


public class DomainAction1  extends ActionSupport  {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;



	private DomainBean listbean;
	
	

	private List<DomainBean> domList;// bean array list for Domain (child).
	private List<DomainBean> dtList; // bean array list for Domain type(parent)
	
	private Integer dt_oid;
	
		
	/**
	 * 
	 */
	
	public String loadDomainType(){
		// Class used to get the domaintype from domaintype table
		
		String result=SUCCESS;
		try {
			List loadDomainType = DomainDAO.loadDomainType();
			dtList=loadDomainType;
		} catch (Exception e) {
			// TODO Auto-generated catch block;
			result=ERROR;
			e.printStackTrace();
		}
		
		
		return result;
	}
	
	public String addupDomain(){// Class used to insert a value or execute an update query based on object id from domain table.(Logic in  DAO class)
		String result= SUCCESS;	
		System.out.println("Inside AddDomain");
		if(listbean!=null){
			try {
				if(DomainDAO.addupDomain(listbean)){
					result= SUCCESS;
					System.out.println("Adding a tuple");
				}
				
					else {
						result=ERROR;
					}
				}
			catch (Exception e) {
				
				result= null;
				listbean=null;
				System.out.println("Adddomain isnt working.");
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		else{
			result=INPUT;
			
		}
		listDomain(dt_oid);
		return result;
	}

	
	public String listDomain(Integer dt_oid)
	{										// Used to display records from domain table . Using an iterator tag in the 
		String result= SUCCESS;

		
		try {
			domList=DomainDAO.listDomain(dt_oid);
			System.out.println("Listing domain");
			return result;
			
		
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			result=null;
			return result;
		}
		
	}
	
	public String obtainData(Integer objid){ // used to obtain a single row from the domain table and repopulate the corresponding fields in drop down and checkboxes.
		
		String result= ERROR;
		if(listbean!=null){
			try {
				result= SUCCESS;
				listbean =DomainDAO.obtainData(objid);
			} catch (Exception e) {
				result=ERROR;
				listbean=null;
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
		return result;
		
	}
	
	
	public DomainBean getListbean() {
		return listbean;
	}

	public void setListbean(DomainBean listbean) {
		this.listbean = listbean;
	}

	public void setDomList(List<DomainBean> domList) {
		this.domList = domList;
	}

	public List<DomainBean> getDomList() {
		return domList;
	}

	public Integer getDt_oid() {
		return dt_oid;
	}

	public void setDt_oid(Integer dt_oid) {
		this.dt_oid = dt_oid;
	}

	public void setDtList(List<DomainBean> dtList) {
		this.dtList = dtList;
	}

	public List<DomainBean> getDtList() {
		return dtList;
	}
	
}

DomainBean.java

ublic class DomainBean implements Serializable  {
	
	private String domainType;
	private String  code;
	private String description;
	private boolean  active;
	private boolean edit;
	private int dt_oid;
	private ArrayList domainList;
	private String StatusActive;
	private String StatusEdit;
	private String message;
	
	
	private int hdnDomainId;
	private Integer  objid;// to get link ..
	ArrayList<DomainBean> listDetails = new ArrayList<DomainBean>();
	ArrayList<DomainBean> dtList = new ArrayList<DomainBean>();
	

	
	public void setDomainType(String domainType) {
		this.domainType = domainType;
	}

	public String getDomainType() {
		return domainType;
	}

	public void setCode(String code) {
		this.code = code;
	}

	public String getCode() {
		return code;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	public String getDescription() {
		return description;
	}

	public void setActive(boolean active) {
		this.active = active;
	}

	public boolean getActive() {
		return active;
	}

	public void setEdit(boolean edit) {
		this.edit = edit;
	}

	public boolean getEdit() {
		return edit;
	}

	public ArrayList getDomainList() {
		return domainList;
	}

	public void setDomainList(ArrayList domainList) {
		this.domainList = domainList;
	}

	public void setDt_oid(int dt_oid) {
		this.dt_oid = dt_oid;
	//System.out.println("in Vo dtoid is "+dt_oid);
	
	}

	public int getDt_oid() {
		return dt_oid;
	}

	public void setObjid(int objid) {
		System.out.println("I am setting the value as "+objid);
		this.objid = objid;
	}

	public Integer getObjid() {
		return objid;
	}

	public void setHdnDomainId(int hdnDomainId) {
	System.out.println("the Domain ID in VO:"+hdnDomainId);
		this.hdnDomainId = hdnDomainId;
	}

	public int getHdnDomainId() {
		return hdnDomainId;
	}

	public void setStatusActive(String statusActive) {
		StatusActive = statusActive;
	}

	public String getStatusActive() {
		return StatusActive;
	}

	public void setStatusEdit(String statusEdit) {
		StatusEdit = statusEdit;
	}

	public String getStatusEdit() {
		return StatusEdit;
	}

	public void setMessage(String message) {
		this.message = message;
	}

	public String getMessage() {
		return message;
	}
	public void setObjid(Integer objid) {
		this.objid = objid;
	}

	public ArrayList<DomainBean> getDtList() {
		return dtList;
	}

	public void setDtList(ArrayList<DomainBean> dtList) {
		this.dtList = dtList;
	}
	
	

}

P.S How do i attach files on here , i tried attaching my source code using .java, .txt, .doc and the system rejects it , what format should i use to attach my code, in the form of files?
Thanks.

[Tom Rispoli]

At first glance this looks right, how are you calling the loadDomainType method in your action class? Can you please show the code or config that is doing it? Have you verified that it is getting called?

[Vic Hood]

Im calling the loadDomainType function through the struts.xml which ive placed below .
<struts> <constant name="struts.enable.DynamicMethodInvocation" value="false" /> <constant name="struts.devMode" value="false" /> <constant name="struts.custom.i18n.resources" value="ApplicationResources" /> <package name="default" extends="struts-default" > <action name="loadDomainType" class="com.vivek.struts2.action.DomainAction1" method="loadDomainType"> <result name="success">/jsp/interface.jsp</result> </action> <action name="listDomain" class="com.vivek.struts2.action.DomainAction1" method="listDomain"> <result name="success">/jsp/interface.jsp</result> </action> <action name="addupDomain" class="com.vivek.struts2.action.DomainAction1" method="addupDomain"> <result name="success">/jsp/interface.jsp</result> <result name="error">/jsp/header.jsp</result><!-- Pages placed just to help in detecting that the flow of logic is incorrect --> <result name="input">/jsp/footer.jsp</result><!-- Pages placed just to help in detecting that the flow of logic is incorrect --> </action> <action name="obtainData" class="com.vivek.struts2.action.DomainAction1" method="obtainData" > <result name="success">/jsp/interface.jsp</result> </action> </package> </struts>

And my jsp is as follows.

<html>
	<head>
    <title>Domain Master</title>
	
	<link href="<s:url value="/css/wss.css"/>" rel="stylesheet" type="text/css"/></head>
 	</head>
 	
	<body>

	  
	  
	  <TABLE width="100%" height="100%" border="1" cellspacing="0"
	cellpadding="0">
	<TR>
		<TD height="75" class="header"><%@ include file="/jsp/header.jsp"%>
		</TD>
	</TR>
	<TR>
		<TD height="30" class="menu"><%@ include file="/jsp/Menu.jsp"%>

		</TD>
	</TR>
	
	<TR>
		<TD class="content" valign="top">
		<TABLE class="DocMasterBodyTable">
	
	
			 <s:form action="addupDomain" method="post">
			 <input type="hidden" name="listbean.objid"  value="<s:property value="listbean.objid"/>"/>
	 
	  <TR class="odd">
				<TD class="cssLabel">DomainType</TD>
				<TD class="cssComboBox">	
						<s:select list="dtList" listKey="dt_oid"  listValue="code"   headerKey="0" headerValue="D.T DropDown " label="DomainType"></s:select><!-- throws error-->
	
	
	<TR class="even">
				<TD class="cssLabel">Code</TD>
				<TD class="cssComboBox">
					<s:textfield name="listbean.code" > </s:textfield>
				
				</TD>
				<TD></TD>
				<TD class="cssLabel">Description</TD>
				<TD class="cssComboBox"><s:textfield name="listbean.description"></s:textfield>
			</TR>
	
	<TR class="odd">
				<TD class="cssLabel">Active</TD>
				<TD><s:checkbox name="listbean.active" ></s:checkbox></TD>
				<TD></TD>
				<TD class="cssLabel">Editable</TD>
				<TD><s:checkbox name="listbean.edit" ></s:checkbox></TD>
			</TR>
	<TR class="even">
				<TD colspan="5" align="right"><s:submit/>
				<s:reset label="Clear"></s:reset>	</TD>	

			</TR>
	
	</s:form>
	
</TABLE>
<s:if test="domList != null && list.size > 0"> 
 				  			<TABLE class="DocMasterFooterTable" width="75%" border="1">
			<TR>

				<TD>Code</TD>
				<TD>Description</TD>
				<TD>IsActive?</TD>
				<TD>IsEditable?</TD>

			</TR>	
		</TABLE>
 
     <s:iterator value="domList" >  
        <s:property value="code"/>  
        <s:property value="description"/>  
        <s:property value="active"/>  
        <s:property value="edit"/>  
    
    	<a href>="<s:url action="obtainData" > <s:param name="objid" value="%{objid}" ></s:param>  </s:url>"
    		<td><input type="submit" value="Audit Trail"/></td>
    	</a>
    	</TD>
    	
    	
    	    </s:iterator>  
    </s:if>
   
      <TR>
		
		<TD class="footer"><%@ include file="/jsp/footer.jsp"%>

		</TD>
	</TR>
</TABLE>
      
	</body>
	
</html>

[Tom Rispoli]

Ok, at first glance the config looks right too. Can you put some logging into your action class after

dtList=loadDomainType;

to verify that dtList is actually being populated with some values?

[Vic Hood]

Hi Tom,
Thanks for replying .
could you please check your PM.

Thanks