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+1 A:

Apart from "don't do it that way", I guess you could test the type of updatedDate:

<c:choose>
    <c:when test="${review.updatedDate.class.name == 'java.util.Date'}">
     Date: ${review.updatedDate}
    </c:when>
    <c:otherwise>
     Map: ${review.updatedDate._value}
    </c:otherwise>
</c:choose>

...assuming that the date is an instance of the Date class. Strangely, this approach didn't work when I tried to test for java.util.HashMap.

Perhaps a more reliable approach would be to hand the test off to a Java class:

package typetest;

import java.util.Map;

public class TypeUtil {

    public static boolean isMap(Object o) {
     return o instanceof Map;
    }

}

This can be mapped to a custom function via a TLD file (e.g. WEB-INF/maptest.tld):

<?xml version="1.0" encoding="UTF-8"?>
<taglib xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"
    version="2.1">
    <tlib-version>1.0</tlib-version>
    <short-name>myfn</short-name>
    <uri>http://typeutil&lt;/uri&gt;
    <function>
     <name>isMap</name>
     <function-class>typetest.TypeUtil</function-class>
     <function-signature>boolean isMap(java.lang.Object)</function-signature>
    </function>
</taglib>

Sample JSP that imports the function:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%&gt;
<%@ taglib prefix="myfn" uri="http://typeutil"%&gt;
<html>
<body>
<c:choose>
    <c:when test="${myfn:isMap(review.updatedDate)}">
     Map: ${review.updatedDate._value}
    </c:when>
    <c:otherwise>
     Date: ${review.updatedDate}
    </c:otherwise>
</c:choose>
</body>
</html>

McDowell 2009-07-05 21:07:34

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JSTL: check if property doesn't exist

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