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How to display different values ​​from different types of objects in one data table?

I have an object (Ticket) that has a list of other objects (Message). The message is abstract and has several subclasses - for example, EditMessage, CreationMessage, etc. So the Ticket object contains a mixture of these messages, and they are ordered by the time they were created.

Now I want to display all these messages on the Facelets page, and I need to display the values ​​of the fields specific to this type of message: for example, the editedField in EditMessage, userName in CreationMessage, ...

The most obvious way seems to be h: dataTable:

<h:dataTable value="#{ticketController.ticket.messages}" var="msg" >
    // determine type of message, cast, and use <c:if> to output needed values
</h:dataTable>

The problem is that the Facelets expression language does not have "instanceof" and casts. As far as I can tell, this can be solved with some ugly rounding to a managed bean, defining a message type in standard Java, returning a message of the desired type, etc.

Is there a better, more clear and concise way to do this?

<h / "> <B> Solution

My main problem was the <c: if> tag. It turned out to be a JSTL tag, so it has a slightly different rendering life cycle. Instead, I now use <h: panelGroup> and its "rendered" attribute.

Some codes:

<h:dataTable value="#{ticketController.ticket.messages}" var="msg" >
    <h:column>
        <h:panelGroup rendered="#{msg.class.name == 'org.rogach.tsnt.TextMessage'}" >
            <h:outputText value="msg.text" />
        </h:panelGroup>
        <h:outputText value="#{msg.creationTime}" />
    </h:column>
</h:dataTable>

And no throw is ever needed.

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instanceof .
: <c:if test="${xxx.class.name == 'CreationMessage'}"> c: EL. , , , .

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