Re: [morph-developer] Damn Verizon

[Matt S. <Mat...@wh...>]

Comments inline....
> :)  I think making expressions perfectly safe for this
> copier will require more knowledge of how the
> expression is parsed, along the lines of my
> earlier-voiced thoughts about expressions in Morph. 
> Maybe I'll try to cook up a BC implementation of this.
>   
One of my original frustrations with BeanUtils is when it encountered 
something unexpected it would blowup at you and ruin your day.  With 
Morph I strove to just silently fail where possible and only throw 
exceptions when something really boneheaded happened (like trying to 
convert "hello world!" to an Integer).

I'm pretty sure what will happen if you enter a totally bogus expression 
is you'll get a blowup.  If you enter an expression for an object path 
and a null is encountered part way through, I'm pretty sure a null will 
just be returned.

Don't be intimidated by the expression parsing stuff, it's really very 
trivial (in fact SimpleExpressionParser has less than a dozen lines of 
code).  Basically the expression parser is just a StringTokenizer that 
looks for symbols usually found in languages like . [ ] ( ) and then 
just treats them all as word breaks.  So something.funky]like[this in 
Morph is equivalent to something.funky.like.this in a more strict 
language like JSTL.  Why be so strict with your syntax when the whole 
point of this new syntax (as opposed to strongly typed Java calls) is to 
ignore types and make things easier on yourself? ;)

Then for the Language implementation we just traverse the object graph 
in a loop and try our best to get what was requested:

public Object getImpl(Object target, String expression) throws Exception {
    if (ObjectUtils.isEmpty(expression)) {
        return target;
    }

    Object value = target;
   
    String[] tokens = expressionParser.parse(expression); // { 
"something", "funky", "like", "this" }
    for (int i=0; i<tokens.length; i++) {
        String token = tokens[i];
        if (value == null) { // just return null, no blowup
            return null;
        }
        value = getReflector().get(value, token); // yay found 
something!  go get it
    }
   
    return value;
}

> Oh, and I forgot to say before that yes, I will
> probably be grateful for help with jots and tittles
> wrt the release.  And just to be sure we're on the
> same page, we're talking 1.0.1, correct?
>   
Actually I released 1.0.1 last year but never updated the homepage since 
it's such a huge PITA.  Next could be 1.0.2 but even if it's still in 
the sandbox your new stuff might merit a 1.1 designation ;)  Up to you...

Matt S