Question

I am writing a small web app using servlets and JSP ( no additional frameworks ).

There is a page that displays all groups in the DB. There is a possibility to edit the entry, by pressing a button that will redirect to page "editGroup?id=1". So, the target serlvet finds to group with the provided id, populates the request with that bean and make a forward to a JSP page:

        <form action="addGroup.html" method="post">
            Group name : <input type="text" name="name" value="${group.name }"/><br /> 
            Group description : <input type="text" name="description" value="${group.description }"/><br /> 
            Group roles :
            <c:forEach var="role" items="${roles}">
                <input type="checkbox" name="roles_id" value="${role.id}" />${role.name}<br />
            </c:forEach>
            <input type="submit" value="Submit">
        </form>

The question is : how to preselect the roles that already are attached to the group ?
The group’s bean has a list of beans Role. The request also has set an attribute that store the list of all available roles.

So inside of the loop I need to check if that role is already attached to the edited group.

Please help.

Answer 1

After some investigations I found the solution in this question:

<c:forEach var="role" items="${roles}">
    <c:choose>
        <c:when test="${group.roles.contains(role)}">
            <input type="checkbox" name="roles_id" value="${role.id}" checked="checked"/>${role.name}
        </c:when>
        <c:otherwise>
            <input type="checkbox" name="roles_id" value="${role.id}"/>${role.name}
        </c:otherwise>
    </c:choose>
</c:forEach>

Using expression like : ${group.roles.contains(role)}

or this way (thank you, BalusC ! )

<c:forEach var="role" items="${roles}">
    <input type="checkbox" name="roles_id" value="${role.id}" ${group.roles.contains(role) ? 'checked' : ''}/>${role.name}      
</c:forEach>