Uninitialize a property when unselecting data from html:optionsCollection

[Francois Bourgault]

Hi,

When I select from a system list(populated using optionsCollection ) it works very well. For instance, systemname[0] = '21' if I select the 1st system in the list. Problem is when I unselect that system. systemname[0] is still = '21' when it should be = to '' or null

When I trace the code, I can see the setSystemName() being executed when I select a system. But the same method isn't executed when I unselect the system I selected before. So, systemname[0] is still = '21' and nothing is selected on the window. How do I get around that problem when I unselect all data in a optionsCollection? I don't want to use the reset button for this. Below I added code from the formbean and jsp page.


thanks.

In struts-config, action for the search form..
<action path="/smtSearch" type="gov.mdot.webapp.smt.control.action.SearchAction"
name="SearchForm"
input="/jsp/Search.jsp"
delegater="gov.mdot.webapp.smt.delegate.SearchDelegateImpl"
scope="session"
validate="true" >
<forward name="success" path="/jsp/Search.jsp"/>
</action>


// formbean
private String systemName[]

// jsp page
<TD align="left" valign="top">
<html:select property="systemName" size="10" multiple="multiple">
<html:optionsCollection name="SearchForm" property="systemList"/>
</html:select>
</TD>

[Bear Bibeault]

Please be sure to ask Struts-related questions in the Struts forum. This topic has been moved there for you.

[Merrill Higginson]

This problem is due to a quirk in HTML. If the user selects no options in a <select> input, nothing gets sent back to the server for that input, and hence Struts doesn't call the setter.

In this case where your ActionForm is in session scope, you must override ActionForm's reset() method, and in that method you must set the systemname array to an empty array. Example:

@Override
public void reset(ActionMapping mapping, HttpServletRequest request) {
systemname = new String[0];
}

Struts calls the reset method prior to calling the setters. Therefore, if the user does select an option, the setter will be called and will replace the empty array with the values selected.

[Francois Bourgault]

I tried that and it works. But what if I added errors in the ActionErrors class in the validate() method? The user will see all error messages. Will he/she need to re-enter all the data again?

[Merrill Higginson]

Originally posted by Francois Bourgault:
Will he/she need to re-enter all the data again?

No. Here is the order in which Struts calls methods on your ActionForm class:

1-reset()
2-the setters (setX(), setY(), etc.)
3-validate()

When you clear data in your reset method, it's immediately re-populated with what the user entered when Struts calls the setters. By the time the validate method is called, the fields are populated properly, and if the JSP is redisplayed because of an error, it will show the data the user entered.

[Francois Bourgault]

It works. Thanks for the clarification.