Re: java.util.Properties extending from HashMap<Object, Object> instead
of HashMap<String, String>
Zig wrote:
but note one difference:
"Properties whose key or value is not of type String are omitted"
Yes, but more importantly,
Because Properties inherits from Hashtable, the put and putAll methods
can be applied to a Properties object. Their use is strongly discouraged
as they allow the caller to insert entries whose keys or values are
not Strings. The setProperty method should be used instead.
If the store or save method is called on a "compromised" Properties object
that contains a non-String key or value, the call will fail. Similarly, the
call to the propertyNames or list method will fail if it is called on a
"compromised" Properties object that contains a non-String key.
Zig wrote:
I think this is an indication that, while Properties are *meant* for
Strings, there may be existing code which uses them for other things.
Not if their authors read the Javadocs there isn't.
Current developers using those APIs may need some awareness that, if the
Properties has passed through a 3rd party API, the developer is not
guaranteed that casting each key or value to a String will be successfull.
It had better be, and no casting should be needed.
<http://java.sun.com/javase/6/docs/api/java/util/Properties.html#getProperty(java.lang.String)>
takes and returns String anyway, so why cast? Likewise with
<http://java.sun.com/javase/6/docs/api/java/util/Properties.html#setProperty(java.lang.String,%20java.lang.String)>
I just don't get all this silly talk about using non-String items in a Properties.
* The type has to be <Object,Object> due to backwards compatibility
issues for APIs which used Properties in ways it was not intended for.
That's not it. It's because that's the only backward-compatible type for a
class that came from 1.0 days. It's for APIs that used Properties in ways
that it *was* intended for.
I think it would be useful if Properties were more Map-like. One might
But then it would be less Properties-like.
Oh well, I guess that's just nit-picking. Maybe Apache Commons
Collections will offer some good replacements in the future.
Unlikely, since Properties does the job just fine already.
--
Lew