String.contains(CharSequence) calls toString on argument

[Tomasz Kowalczewski]

It is more about custom implementations of CharSuqence that may be backed
by some exotic matter and calling toString on them to create actual String
goes against purpose of CharSequence in the first place (esp. when passing
it to a method that accepts CharSequence). For JDK user it is easy to avoid
calling contains and roll his/her own implementation but it would be nice
if we can avoid such surprises.


On Fri, Mar 20, 2015 at 1:31 PM, Aleksey Shipilev <
aleksey.shipilev at oracle.com> wrote:

> On 03/20/2015 03:28 PM, Aleksey Shipilev wrote:
> > I wonder if the change is "only" about specializing
> > indexOf(CharSequence) on the Java side to shortcut to indexOf(String)
> > and others, like String.contentEquals(CharSequence) already does.
>
> Ah, sorry for the confusion, contains(CharSequence) already
> "specializes" via shortcut in
>
>   String toString() {
>       return this;
>   }
>
>   public boolean contains(CharSequence s) {
>      return indexOf(s.toString()) > -1;
>   }
>
> So the question is about StringBuffers/StringBuilders then?
>
> -Aleksey.
>
>


-- 
Tomasz Kowalczewski