[Springframework-developer] styling string values consistently

[Keith D. <kd...@cs...>]

Ahile back I ran across this point Howard Lewis Ship made on the
DebugInterceptor's handling of argument styling (particularly arrays):

"You can see [below] the Debug interceptor catching the invocations of
toString() as well as add(). It doesn't do a great job [rendering]
arguments."

Debug interceptor: count=2 invocation=[Invocation: method=[public abstract
int springex.Adder.add(int,int)] args=[Ljava.lang.Object;@1b9240e] target is
of class springex.impl.AdderImpl]

I've since created some utility interfaces/classes that encapsulate string
styling algorithms for any type of object (arrays, maps, classes, methods,
invocations, entries, null, etc.) and placed them in the sandbox under
sandbox/util.  Internally the implementation leverages the visitor pattern
to nicely encapsulate styling algorithms (specifically a form of visitor
based on reflection.)

The classes are:

ObjectStyler (interface) - a generic interface - a single style(Object)
method accepts an object, returns the styled string form.

DefaultObjectStyler - styles an object according to Spring conventions.  I
don't know all the styling conventions, so feel free to polish this class if
I styled a particular type of object incorrectly (or add new styled types.)

There is also a class called ToStringBuilder (which uses a ToStringStyler,
which delegates to an ObjectStyler for styling field values) to style
toString() method output flexibly yet consistently and with less LoC.  I got
the ideas for this from jakarta-lang (though my implementation differs
considerably).  I also got the idea for combining visitor with reflection
from Bob Lee.

I think these would be a nice addition to the core.util module post 1.0.
Keith