Question

I have a Spring MVC form:select whose form:options are bind with a List<Custom_Object>. The List<Custom_Object> is named as LOCALIZATION_LIST in the code below.

The path attribute of form:select is used to set the selected option.

<form:form action="editNode.do" method="post" name="editNodeForm" commandName="editElementDetails">
  <table>
    <tr>
      <td>Data Type</td>
      <td>
       <form:select path="datatype" onchange="" cssClass="large" id="datatypes">
        <c:if test="${! empty LOCALIZATION_LIST}">
          <form:options items="${LOCALIZATION_LIST}" itemLabel="local_Name" itemValue="local_Name"/>
        </c:if>
       </form:select>
      </td>
    </tr>   
  </table>
</form:form>

Now my problem is that there might be a scenario when editElementDetails.datatype may contain a value which is not there in LOCALIZATION_LIST at all. So currently Spring MVC shows the first element of LOCALIZATION_LIST as selected.

Is there a way I can figure out whether the bind action for setting the selected object in form:options of form:select was successful or not?

So that when the binding was not successful, I can then add one extra form:option with the new value in the form.

Answer 1

Note: Answering my own question

I figured it out for now by manually searching for the incoming command object field value in the LOCALIZATION_LIST and if not found, adding an extra form:option corresponding to it.

I was hoping to find a JSTL/Spring-MVC out-of-box solution for this though.

Here is the code:

<form:form action="editNode.do" method="post" name="editNodeForm" commandName="editElementDetails">
  <table>
    <tr>
      <td>Data Type</td>
      <td>
       <form:select path="datatype" onchange="" cssClass="large" id="datatypes">
        <c:if test="${! empty LOCALIZATION_LIST}">
          <c:set var="contains" value="false" />
          <c:forEach var="item" items="${LOCALIZATION_LIST}">
            <c:if test="${item eq editElementDetails.datatype}">
              <c:set var="contains" value="true" />
            </c:if>
          </c:forEach>
          <c:if test="${ !contains }">
            <form:option label="${editElementDetails.datatype}" value="${editElementDetails.datatype}"/>
          </c:if>
          <form:options items="${LOCALIZATION_LIST}" itemLabel="local_Name" itemValue="local_Name"/>
        </c:if>
       </form:select>
      </td>
    </tr>   
  </table>
</form:form>