Indexed property in struts

The simplest demonstration of using indexed properties in Struts can be shown with the following simple bean and JSP page:

package org.apache.struts.webapp.exercise;
import org.apache.struts.action.ActionForm;
public class StringBean extends ActionForm {
    private String strAry[] = { "String 0", "String 1", "String 2", "String 3", "String 4" };

    public String getStringIndexed(int index) { 
        return strAry[index]; 
    }
    
    public void setStringIndexed(int index, String value) { 
        strAry[index] = value; 
    }
}

First note the two methods in the StringBean class, "getStringIndexed()" and "setStringIndexed()". Note that the "get" method takes an "int" and the "set" method takes an "int" and "String". The Beanutils package and Struts recognizes this arrangement of signatures as an "indexed property", in this case with the property name "stringIndexed".

<!-- indexedtest.jsp -->
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<jsp:useBean id="bean" class="org.apache.struts.webapp.exercise.StringBean"/>
<bean:write name="bean" property="stringIndexed[1]"/>

Note the property value of "stringIndexed[1]". This is intended to reference the indexed property "stringIndexed", and the 1st (zero-based) entry of whatever array or collection which the indexed property represents.

As you might be able to guess, when this page is executed, it will print just the string "String 1", which is the corresponding array entry at that index value.

This is a simple demonstration of what indexed properties can provide.