[BEANUTILS-61] PropertyUtilsBean isReadable() and isWriteable() methods do not work correctly for WrapDynaBean

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Nightly Builds
• Fix Version/s: 1.8.0
• Component/s: DynaBean

Environment

Operating System: other
Platform: All

• Bugzilla Id: 35240
• Assignee: Niall Pemberton
• Reporter: Brian Ewins
• Created: 06/Jun/05 23:58
• Updated: 25/Mar/08 08:07
• Resolved: 05/Jul/07 01:16

Description

Try this: given any pojo class MyBean.java,

MyBean orig = new MyBean();
MyBean dest = new MyBean();
DynaBean db = new WrapDynaBean(dest);
PropertyUtils.copyProperties(db, orig);

You'll see an exception like:
java.lang.IllegalArgumentException: Property 'class' has no write method
at org.apache.commons.beanutils.WrapDynaBean.set(WrapDynaBean.java:266)

This surprised me because 'copyProperties()' does an 'isWritable()' check before
it sets properties. However, what PropertyUtilsBean.isWritable actually does is
this:
if (bean instanceof DynaBean) {
// All DynaBean properties are writeable
return (((DynaBean) bean).getDynaClass().getDynaProperty(name) != null);
} ...

That's plainly wrong for a WrapDynaBean, since pretty much every wrapped object
has a non-writable 'class' property.

A workaround for the immediate problem:
if (db instanceof WrapDynaBean) {
PropertyUtils.copyProperties(((WrapDynaBean) db).getInstance(), src);
} else {
PropertyUtils.copyProperties(dest, src);
}

... the problem affects isReadable and isWritable, and hence copyProperties; to
fix it for all cases would (I think) require unwrapping any WrapDynaBeans passed
into those calls.

I guess having a situation where you'd use PropertyUtils /and/ WrapDynaBeans is
fairly unusual so this is just a minor bug.