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Re: streams list in list reduce

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I have found a solution myself, I use .flatMap( i -> i.exec() ).collect( Collectors::toList() )

Thanks for help

Phil


Am Donnerstag, 17. Dezember 2015 03:14:31 UTC+1 schrieb Arne Vajhøj:
> On 12/16/2015 5:52 AM, Philipp Kraus wrote:
> > I have got a definition like
> >
> > interface Execute { Collection<Term> exec(); }
> >
> > and run vai streams over my data
> >
> > List<Execute> x; // x is filled
> >
> > And I would like to create List<Term> y = x.stream().map( i ->
> > i.exec()).collect( ?? toList() );
> >
> > I would like to run addAll on the collect and build a concatinated
> > list if all lists which are return by the exec method. How can I
> > create this concatinated list?
> 
> Demo of one approach:
> 
> import java.util.ArrayList;
> import java.util.Collection;
> import java.util.List;
> 
> public class LotsOfLists {
> 	public static interface Execute
> 	{
> 	     public Collection<Integer> exec();
> 	}
> 	public static class ExecuteImpl implements Execute {
> 		private List<Integer> data = new ArrayList<>();
> 		public ExecuteImpl(int... vals) {
> 			for(int val : vals) data.add(val);
> 		}
> 		@Override
> 		public Collection<Integer> exec() {
> 			return data;
> 		}
> 	}
> 	public static void main(String[] args) {
> 		List<Execute> x = new ArrayList<>();
> 		x.add(new ExecuteImpl(1));
> 		x.add(new ExecuteImpl(2, 3));
> 		List<Integer> res = x.stream().collect(ArrayList<Integer>::new, 
> (acc,elm) -> acc.addAll(elm.exec()), ArrayList<Integer>::addAll);
> 		System.out.println(res);
> 	}
> 
> }
> 
> Arne

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streams list in list reduce Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2015-12-16 02:52 -0800
  Re: streams list in list reduce Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-12-16 09:23 -0500
  Re: streams list in list reduce Arne Vajhøj <arne@vajhoej.dk> - 2015-12-16 21:14 -0500
    Re: streams list in list reduce Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2015-12-16 23:41 -0800

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