Flatmap example

[mohan.radhakrishnan at polarisFT.com]

That are 2 variants that compile. I mistook code folding for a new 
pattern.

Mohan



From:   Mohan Radhakrishnan/BSC31/polarisFT
To:     lambda-dev at openjdk.java.net
Date:   12/03/2013 09:48 AM
Subject:        Re: Flatmap example


I am using 113 and it compiles.. But I realized there are 3 variants.

        //Style 1
        patterns.stream()
                .flatMap(new Function<Pattern, Stream<String>>() {
                    @Override
                    public Stream<String> apply(Pattern p) {
                        return source.stream()
                                .map(p::matcher)
                                .filter(Matcher::find)
                                .map(Matcher::group);
                    }
                })
                .forEach(System.out::println);

        //Style 2
        patterns.stream().flatMap(( Pattern p1 ) -> source.
                stream().
                map(p1::matcher).
                filter(Matcher::find).map(matcher -> 
matcher.group())).forEach(x -> System.out.println(x));

        //Style 3
        patterns.stream()
                .flatMap(new Function<Pattern, Stream<String>>() {
                    @Override
                    public Stream<String> apply(Pattern p) {
                        return source.stream()
                                .map(p::matcher)
                                .filter(Matcher::find)
                                .map(Matcher::group);
                    }
                })
                .forEach(System.out::println);

Thanks,
Mohoan




From:   Paul Sandoz <paul.sandoz at oracle.com>
To: 
Cc:     "lambda-dev at openjdk.java.net" <lambda-dev at openjdk.java.net>
Date:   12/02/2013 08:42 PM
Subject:        Re: Flatmap example
Sent by:        lambda-dev-bounces at openjdk.java.net




On Dec 2, 2013, at 3:31 PM, "Millies, Sebastian" 
<Sebastian.Millies at softwareag.com> wrote:

> I can't get the second variant (without the inner class) to compile with 
b117.
> 

Compiles and runs for me against the tip of tl.


> The method reference in ".map(p::matcher)" seems illegal, and explicitly 
typing the Lambda-Parameter
> "p" as "Pattern" leads to an Incompatible Types error. I have to cast 
the function that goes into the flatMap
> to "Function<Pattern, Stream<String>>". Why is that?
> 

I guess passing compile glitch or bug that was recently fixed.

Paul.





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