Question

I am attempting to validate my object that encapsulates a list of other objects, as follows (shortened for brevity):

public class FormDTO {
private List<AttributeDTO> ruleAttributes;
// More attributes here
}

public class AttributeDTO {
private String value;
// More attributes here
}

A snippet of my validator is as follows:

for(AttributeDTO attributeDTO : attributes)
{
    if(attributeDTO.getValue() == null || attributeDTO.getValue().length() == 0)
    {
        errors.reject("value", "value.isEmpty");
    }
}

My jsp contains the following:

<c:forEach items="${form.ruleAttributes}" var="ruleAttribute" varStatus="counter">
    <tr>
        <td>
            <c:choose>
                <c:when test="${ruleAttribute.isEditable}">
                    <form:input path="ruleAttributes[${counter.index}].value" value="${ruleAttribute.value}"/>
                </c:when>
                <c:otherwise>
                    <span class="derived">NotEditable</span>
                </c:otherwise>
            </c:choose>
        </td>
        <td>
            <form:errors path="ruleAttributes[${counter.index}].value"/>
        </td>
    </tr>
</c:forEach>

How do I get the corresponding error message to appear for the relevant list item? In summary, I want the “value.isEmpty” message to appear in the table cell for the relevant row that has an empty value.

Thanks

Answer 1

After reading the Spring reference guide again, I can answer this question myself.

To get the appropriate error to appear for this snippet…

<form:errors path="ruleAttributes[${counter.index}].value"/>

…I need to modify my validation code as follows:

for(int i = 0; i < ruleAttributes.size(); i++)
{
AttributeDTO attributeDTO = ruleAttributes.get(i);

if(attributeDTO.getValue() == null || attributeDTO.getValue().length() == 0)
{
        errors.rejectValue("ruleAttributes[" + i + "].value", "value.isEmpty", "Value should not be empty");
}

}