You can also create a "valueOf" method that takes a string value and
returns the proper enumeration instance, which is how Castor deals with
unmarshalling type-safe enumerations:
public static [object-type] valueOf(String enumValue) {
}
--Keith
-------- Original Message --------
Subject: Re: [castor-dev] NotConstructable Exception and FieldHandler
Date: Mon, 16 Dec 2002 11:55:54 -0800
From: "Chris Bedford" <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
References: <[EMAIL PROTECTED]>
Hi, Matthias: I'm no Castor expert,but I can tell you that
Class.newInstance() requires a no argument constructor be available on
theClass whose instance you are trying to construct. From the
Javadocs-> ****************
public Object newInstance()
throws InstantiationException,
IllegalAccessException
Creates a new instance of the class represented by this Class object.
The class is instantiatied as if by a new expression with an empty
argument list. The class is initialized if it has not already been
initialized. **************** As a workaround you could create a
pass-through proxy that for CoordinateFormatEnum that knows how to
constructan instance of a CoordinateFormatEnum. This proxy would
implement all methods of CoordinateFormatEnum and justdelegate the calls
to the embedded CoordinateFormatEnum instance. That's one way... maybe
the Castor guys can suggest a better one.. I'd be interested in
finding out as well since I find creationof these proxies to be a
hassle.. but they get the job done. thanks Chris
----- Original Message -----
From: Matthias David
To: [EMAIL PROTECTED]
Sent: Monday, December 16, 2002 1:39 AM
Subject: [castor-dev] NotConstructable Exception and
FieldHandler
Hi,
I have written a FieldHandler for a class
(CoordinateFormatEnum) that has no public constructor. When
Unmarshalling I get the following exception:
Nested error: org.exolab.castor.mapping.MappingException: The
Java class CoordinateFormatEnum is not constructable -- it
does not contain a default public constructor)
The problem is that the class CoordinateFormatEnum is a
tool-generated class, so I have no chance to make the
constructor public. So How can this problem be solved? I
thought that the Unmarshaller does not need to call the
constructor of the class since the FieldHandler is responsible
for that, e.g. using the method "newInstance".
Here's the handler's code:
public class CoordinateFormatEnumFieldHandler implements
FieldHandler {
public Object getValue(Object object)
throws IllegalStateException {
return ((Coordinates)object).getFormat().getValue();
}
public void setValue(Object object, Object value)
throws IllegalStateException,
IllegalArgumentException {
((Coordinates)object).setFormat(CoordinateFormatEnum.fromString((String)value));
}
public void resetValue(Object object)
throws IllegalStateException,
IllegalArgumentException {
}
public void checkValidity(Object object)
throws ValidityException, IllegalStateException {
}
public Object newInstance(Object parent)
throws IllegalStateException {
return CoordinateFormatEnum.Mercator;
}
}
And here's the mapping:
<class name="com.Coordinates" access="shared">
<description>Default mapping for
Coordinates</description>
<map-to xml="Coordinates"/>
<field name="format" type="com.CoordinateFormatEnum"
handler="com.CoordinateFormatEnumFieldHandler">
<bind-xml name="Format" node="attribute"/>
</field>
</class>
Any clues for that?
Thanks,
Matthias.
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