RFR: JDK-8005263: Logging APIs takes Supplier<String> for message

[Peter Levart]

Hi Henry,

Have you considered reversing the positions of Supplier and Throwable 
arguments in methods that take both? For example instead of:

  695     public void logEx(Level level, Supplier<String> msgSupplier, Throwable thrown) {


the following:


  695     public void logEx(Level level,Throwable thrown, Supplier<String> msgSupplier) {


If one chooses this form (taking Throwable and Supplier) it might be 
because there is some code in the lambda expression that is turned into 
Suppier that spans multiple lines. Better compact multi-line formatting 
is possible if lambda is last argument:

logger.logEx(
     Level.WARN,
     () -> {
         StringBuilder sb = new StringBuilder();
         for (Foo foo : foos) {
             sb.append(sb.length() == 0 ? "[" : ",");
             sb.append(foo);
         }
         if (sb.length() > 0) sb.append("]");
         return sb.toString();
     },
     exception
);

vs.

logger.logEx(Level.WARN, exception, () -> {
     StringBuilder sb = new StringBuilder();
     for (Foo foo : foos) {
         sb.append(sb.length() == 0 ? "[" : ",");
         sb.append(foo);
     }
     if (sb.length() > 0) sb.append("]");
     return sb.toString();
});


It might be (haven't checked) that you don't need another name for a 
method (logEx) in that case too.

Regards, Peter

On 12/21/2012 07:28 AM, Henry Jen wrote:
> Hi,
>
> This patch adds a couple APIs to java.util.logging.Logger so that
> construction of log messages only occurs when it is actually to be
> logged by using Supplier<String> instead of String.
>
> Since the idea is to avoid unnecessary construction of log messages,
> thus APIs imply formatting are not provided. Thus all forms of logrb and
> log with Parameters are not included.
>
> log with Throwable are named to be logEx or logpEx to avoid null
> ambiguous as it seems like it's quite common usage with
>
> logger.log(level, null, thrown)
>
> Specdiff and webrev can be found at following,
>
> http://cr.openjdk.java.net/~henryjen/ccc/8005263.0/specdiff/diff.html
> http://cr.openjdk.java.net/~henryjen/ccc/8005263.0/webrev/
>
> Cheers,
> Henry