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From: "Damaraju Nagendra Kumar" <damarajun@iictechnologies.com>
To: "'Jakarta Commons Users List'" <commons-user@jakarta.apache.org>
Subject: RE: BeanUtils.populate problem
Date: Thu, 17 Apr 2003 18:12:28 +0530
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-----Original Message-----
From: Jesse Vitrone [mailto:jessevitrone@vitalworks.com]
Sent: Wednesday, April 16, 2003 8:18 PM
To: commons-user@jakarta.apache.org
Subject: BeanUtils.populate problem


I posted something along these lines earlier, but it doesn't really get to
the heart of the problem, so I'm posting something a little more specific.
Here's an example of the problem I'm running into:
 
bean - a bean with some Object on it, like a Person.  In this case, person
on the bean is null.
 
on my properties, I have a "patient.firstName" that has a String value.
 
When I call
    BeanUtils.populate(bean, properties);
 
if my person is null on the bean, then when populate tries to populate it,
it dies, because it winds up trying to call setFirstName on a null person.
 
I would prefer if Commons would just create me a new Person if it needs to
set something on it, but it's null.
 
If I add this to PropertyUtils.getSimpleProperty:
 
        This existed already:
        // Call the property getter and return the value
        Object value = readMethod.invoke(bean, new Object[0]);
 
        Below it, I added:
        if (value == null) {
            try {
                Method writeMethod = getWriteMethod(descriptor);
                if (writeMethod == null) {
                    throw new NoSuchMethodException("Property '" + name +
                            "' has no setter method");
                }
 
                value = readMethod.getReturnType().newInstance();
                writeMethod.invoke(bean, new Object[] {value});
 
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
 
This works just like I want it to :)
 
Do you think people would find something like this useful?  I know I would.
I don't want all the objects on my bean (and the objects on that object,
etc) to have to be initialized already when I try to set them.
 
Does anyone else think that this should be the default behavior?  Or, even
if it's not the default, maybe just be able to pass a flag to force an init
of a null object?
 
Let me know what you think.
 
Jesse