On Dec 30, 6:26 pm, Lew <l...@lewscanon.com> wrote:
yishayj...@hotmail.com wrote:
The following jsp (I named it 'master.jsp') is as simple as I've
gotten it.
=====
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="org.apache.struts.action.ActionMessage"%>
<%@ page import="org.apache.struts.action.ActionMessages"%>
<%! public class MyActionMessages extends ActionMessages {
public java.util.Map getMessages() {
return messages;
}
}
%>
<%
MyActionMessages actionMessages = new MyActionMessages();
actionMessages.add("prop1", new ActionMessage("one"));
session.setAttribute("my_action_message_item",
actionMessages.getMessages().get("prop1"));
%>
<html>
<body>
<span>this is a test: ${my_action_message_item.list}</span><br>
</body>
</html>
====
The message I get is:
org.apache.jasper.JasperException: An exception occurred processing
JSP page /views/profiler/master.jsp at line 20
...
root cause
javax.el.PropertyNotFoundException: Property 'list' not readable on
type java.util.List
javax.el.BeanELResolver$BeanProperty.read(BeanELResolver.java:259)
javax.el.BeanELResolver$BeanProperty.access$000(BeanELResolver.java:
209)
javax.el.BeanELResolver.getValue(BeanELResolver.java:60)
javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
org.apache.el.parser.AstValue.getValue(AstValue.java:97)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:
186)
org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextIm?pl.java:
923)
org.apache.jsp.views.profiler.master_jsp._jspService(master_jsp.java:
77)
==========
This is after the upgrade (see my opening post). Before upgrade the
list is evaluated in the normal toString fasion. I get:
====
this is a test: [one[]]
The object retrieved via 'my_action_message_item' is the one from the call to
actionMessages.getMessages().get("prop1")
'actionMessages.getMessages()' is a Map, 'messages'. A raw Map.
'messages.get("prop1")' returns an Object. 'Object' does not have a method
'getList()'. Boom. But that's not the error. Somehow the system figured out
what the underlying Map types are. Let's follow that chain.
The retrieval from getMessages() is the protected 'messages' element of the
superclass, a HashMap that maps String to an ArrayList. So the result of
get("prop1") is an ArrayList<ActionMessage>.
You then call getList() on that ArrayList. But ArrayList doesn't have such a
method. Now boom.
The exception is correct behavior.
--
Lew- Hide quoted text -
- Show quoted text -
Is the result of get("prop1") an ArrayList? API docs support this
http://struts.apache.org/1.2.4/api/org/apache/struts/action/ActionMessages.html#messages
But if you run the following jsp (you're welcome to try it; it's self
contained):
-----------
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="org.apache.struts.action.ActionMessage"%>
<%@ page import="org.apache.struts.action.ActionMessages"%>
<%! public class MyActionMessages extends ActionMessages {
public java.util.Map getMessages() {
return messages;
}
}
%>
<%
MyActionMessages actionMessages = new MyActionMessages();
actionMessages.add("prop1", new ActionMessage("one"));
Object myObject = actionMessages.getMessages().get("prop1");
session.setAttribute("is_list", new Boolean (myObject
instanceof java.util.List));
session.setAttribute("my_action_message_item", myObject);
%>
<html>
<body>
<span>is list? ${is_list}</span><br>
<span>class name: ${my_action_message_item.class.name}</span><br>
</body>
</html>
---------
You'll get:
---------
is list? false
class name: org.apache.struts.action.ActionMessages$ActionMessageItem
---------
java.util.List. The results you show are correct.
'actionMessages.getMessages()' is a Map, 'messages'. A raw Map.
'messages.get("prop1")' returns an Object.
List even though your code does its level best to hide that fact. It should