Hi,
I posted a message last week with a similar problem. I basically have
several fields on a row in a table, each row containing the same fields
but the number of rows in the table is dynamic and is dependant on a
number of things that aren't defined at compile time.
Although I managed to figure out a workaround based on some other posts
in this group (although not ideal) of sorts and have got the dynamic
form (as described above) to work.
First I have defined a form bean (IterateForm) that contains a Vector
and a constructor capable of initialising it with a fixed number of
blank elements. Each element is another bean (NameForm) which is
essentially a row in the HTML table containing the dynamic fields.
NameForm.java
-------------
public final class NameForm extends ActionForm
{
private String title;
private String forename;
private String surname;
public NameForm()
{
title = "";
forename = "";
surname = "";
}
// getters and setters
IterateForm.java
-----------------
public final class IterateForm extends ActionForm
{
private java.util.Vector names;
// Constructor
public IterateForm(int iNumElements)
{
names = new java.util.Vector(iNumElements);
for(int i = 0; i < iNumElements; i++)
{
NameForm nameForm = new NameForm();
nameForm.setTitle("");
nameForm.setForename("");
nameForm.setSurname("");
names.add(nameForm);
}
this.numRows = Integer.toString(iNumElements);
}
public java.util.Vector getNames()
{
return names;
}
// Don't require setter.
My first JSP index.jsp allows you to specify the number of rows for the
dynamic form.
index.jsp
---------
<html:html locale="true">
<head>
<title>Dynamic Forms Using Struts</title>
<html:base/>
</head>
<body>
<h2>Dynamic Form Using Struts</h2>
<html:form action="/dynaFormSetup.do">
Number of Rows: <html:text property="numRows"/>
<html:submit />
</html:form>
</body>
</html:html>
This page submits its form to the DynaSetupAction action class. This
class then creates a IterateForm (above) using the constructor and
passing it the number of rows for the dynamic form, which initialises
the collection with whatever number of elements you want.
DynaSetupAction.java
--------------------
public final class DynaSetupAction extends Action
{
public ActionForward perform(ActionMapping mapping,
ActionForm form,
HttpServletRequest
request,
HttpServletResponse
response)
throws IOException,
ServletException
{
int numRows =
Integer.parseInt(((DynaSetupForm)form).getNumRows());
HttpSession session = request.getSession();
// Create IterateForm with dynamic number of rows.
ActionForm iterForm = new IterateForm(numRows);
session.setAttribute("iterateForm", iterForm);
// request.setAttribute("iterateForm", iterForm);
return (mapping.findForward("iterationForm"));
}
}
This action then forwards control back to a JSP named IterateForm.jsp.
Which iterates around the collection creating rows the number of rows
specifid from the index.jsp page.
IterateForm.jsp
---------------
<html:html locale="true">
<head>
<title>Dynamic Form Using Struts</title>
<html:base/>
</head>
<body>
<h2>Dynamic Form Using Struts</h2>
<table align="center" width="70%">
<html:form action="/processForm.do" method="POST">
<th>Title</th>
<th>Forename</th>
<th>Surname</th>
<logic:iterate id="names" name="iterateForm" property="names"
type="com.kainos.struts.NameForm">
<tr>
<td><html:text name="names" property="title" indexed="true"/></td>
<td><html:text name="names" property="forename" indexed="true"/></td>
<td><html:text name="names" property="surname" indexed="true"/></td>
</tr>
</logic:iterate>
<tr>
<td colspan="3" align="center">
<html:submit />
</td>
</tr>
</html:form>
</table>
</body>
</html:html>
This page then submits its results to the IterateAction action class
which simply forwards control to the results page DynaFormResults.jsp
which displays them. (See Below).
DynaFormResults.jsp
-------------------
<html:html locale="true">
<head>
<title>Dynamic Form Results Page</title>
</head>
<html:base/>
<body>
<h2>Results of Dynamic Form</h2>
<p>
First Person:<br>
<bean:write name="dynaForm" property="title" scope="request"
filter="false"/>
<bean:write name="dynaForm" property="forename" scope="request"
filter="false"/>
<bean:write name="dynaForm" property="surname" scope="request"
filter="false"/>
</body>
</html:html>
struts-config.xml
------------------
...
<form-bean name="iterateForm" type="com.kainos.struts.IterateForm" />
<form-bean name="name" type="com.kainos.struts.NameForm"/>
<form-bean name="dynaSetupForm"
type="com.kainos.struts.DynaSetupForm"/>
...
<forward name="dynaFormResults" path="/DynaFormResults.jsp"/>
<forward name="iterationForm" path="/IterateForm.jsp"/>
...
<action path="/processForm"
type="com.kainos.struts.IterateAction"
name="iterateForm"
scope="request"
input="/IterateForm.jsp" />
<action path="/dynaFormSetup"
type="com.kainos.struts.DynaSetupAction"
name="dynaSetupForm"
scope="request"
input="/index.jsp" />
...
It isn't an ideal way to do it I suppose but it works for what I need.
Adrian Cunningham.
"Daniel Hinz" <[EMAIL PROTECTED]> wrote in message
news:<[EMAIL PROTECTED]>...
> Hi,
>
> i posted a feature request on struts-dev on friday, which i'd like to
> bring to this forum for dicsussion. Although this has already been
> discussed in some threads, a satifactory conclusion has not been
> reached (at least in my opinion). So here it goes:
>
> A) Use Cases:
> 1) Develop a generic RDMBS Browser using Struts.
> 2) Develop a WebInterface for arbitrary XML editing.
>
> B) Problems in Struts 1.0 and 1.1:
> For each property A the corresonding setA / getA methods are invoked
> upon read/write. There's nothing wrong with that. However i must
> deploy form fields that are unknown to me at compile-time. Thus i
> cannot write a Bean with the appropriate methods.
>
> C) Request for extending org.apache.struts.action.ActionForm:
> A simple solution would be to introduce methods with the following
> signature:
> public void setProperty(String propertyName, Object propertyValue)
> public Object getProperty(String propertyName)
>
> D) Workaround:
> None known to me. There's a class called DynaActionForm which allows
> you to add a dynamic number of fields *in the struts-config.xml file*.
> This is not feasible since the properties are unknown at Servlet
> Initialization time.
>
> I'm quite new to Struts so please forgive me if i missed something
> blatantly obvious.
>
> Regards,
>
> Daniel Hinz
>
> --
> Daniel Hinz
> Software Engineer
> [EMAIL PROTECTED]
>
>
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