On 09/29/2015 06:05 PM, Paul Sandoz wrote:
On 29 Sep 2015, at 12:57, Stephen Colebourne <scolebou...@joda.org> wrote:
Just to note that an ideal location for this would be on a new class,
one that has been discussed before, an "argument checker class".
See Guava Preconditions:
https://github.com/google/guava/blob/master/guava/src/com/google/common/base/Preconditions.java
See Commons Lang Validate:
https://commons.apache.org/proper/commons-lang/javadocs/api-release/org/apache/commons/lang3/Validate.html
See OpenGamma ArgChecker:
http://opengamma.github.io/StrataDocs/apidocs/com/opengamma/strata/collect/ArgChecker.html
https://github.com/OpenGamma/Strata/blob/master/modules/collect/src/main/java/com/opengamma/strata/collect/ArgChecker.java
This was discussed when Objects.requiresNotNull was discussed IIRC.
FTR here is the discussion:
http://openjdk.5641.n7.nabble.com/template/NamlServlet.jtp?macro=search_page&node=2&query=6797535&sort=date
<http://openjdk.5641.n7.nabble.com/template/NamlServlet.jtp?macro=search_page&node=2&query=6797535&sort=date>
AFAICT there was no objection in principle to such classes. I sense that the
objection to going that route was due to an increase in scope and as such it
would overrun it's budget.
I
still think it would be a great addition to the JDK (as every project
has something similar). This issue could be the start, although it
would need a few more methods, guided by the examples above.
Just a few *more* bike sheds to paint :-) I am concerned i will never finish
this nor other un/related tasks.
For now I am ok with Objects being that "argument checker class” simply because
it already has a gravitational pull due to the mass of the existing check methods
[*].
Paul.
[*] I believe it is a backwards compatible to change Objects to extends from
Preconditions and move the existing static check methods to Preconditions. That
seems like a sleazy trick though.
Yes, but the same could be achieved by just re-implementing those 3
methods in Preconditions or delegating from Preconditions to Objects -
without strange subtyping.
I think it's worth introducing Preconditions class. checkNotNull
overloads are equally well suited for Objects as they are for
Preconditions, so it's not wrong to have them in both, while checkIndex
and friends don't really suit any of the existing classes. If I would
have to search for them in among existing classes, Arrays would be the
place to look first. List interface the 2nd. IndexOutOfBoundsException
wouldn't come to my mind, as Exception(s) are usually not homes for
logic, neither would Integer which is to abstract to mentally associate
it with array or list index checks.
Regards, Peter
