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Using streams for a null-safe conversion from an array to list


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8















I'm looking for a succinct way to rewrite a piece of Java code so that it uses streams to convert an array to a list in a null-safe fashion. Here's the original code:



public MailObject toMailObject(final String[] ccAddresses) {
final MailObject mailObject = new MailObject();

// line of code to be altered
mailObject.setCcAddresses(ccAddresses == null
? Collections.emptyList() : Arrays.asList(ccAddresses));

// other necessary code

return mailObject;
}


I've thought of doing something like this:



// psuedocode that obviously doesn't compile
Optional.ofNullable(ccAddresses).SOMETHING.orElse(Collections.emptyList());


where SOMETHING would be along the lines of:



Arrays.stream(ints).collect(Collectors.toList());


but I can't seem to get the syntax quite right.



This question was helpful but didn't exactly address my issue. Could anyone point me in the right direction? I feel like I'm close...



Thank you very much for your time.










share|improve this question




















  • 3





    Your original code seems succinct enough

    – GBlodgett
    4 hours ago











  • Fair enough, but I'm curious as to the best way it can be done using streams.

    – risingTide
    4 hours ago






  • 1





    .map(Arrays::asList)

    – shmosel
    4 hours ago
















8















I'm looking for a succinct way to rewrite a piece of Java code so that it uses streams to convert an array to a list in a null-safe fashion. Here's the original code:



public MailObject toMailObject(final String[] ccAddresses) {
final MailObject mailObject = new MailObject();

// line of code to be altered
mailObject.setCcAddresses(ccAddresses == null
? Collections.emptyList() : Arrays.asList(ccAddresses));

// other necessary code

return mailObject;
}


I've thought of doing something like this:



// psuedocode that obviously doesn't compile
Optional.ofNullable(ccAddresses).SOMETHING.orElse(Collections.emptyList());


where SOMETHING would be along the lines of:



Arrays.stream(ints).collect(Collectors.toList());


but I can't seem to get the syntax quite right.



This question was helpful but didn't exactly address my issue. Could anyone point me in the right direction? I feel like I'm close...



Thank you very much for your time.










share|improve this question




















  • 3





    Your original code seems succinct enough

    – GBlodgett
    4 hours ago











  • Fair enough, but I'm curious as to the best way it can be done using streams.

    – risingTide
    4 hours ago






  • 1





    .map(Arrays::asList)

    – shmosel
    4 hours ago














8












8








8


1






I'm looking for a succinct way to rewrite a piece of Java code so that it uses streams to convert an array to a list in a null-safe fashion. Here's the original code:



public MailObject toMailObject(final String[] ccAddresses) {
final MailObject mailObject = new MailObject();

// line of code to be altered
mailObject.setCcAddresses(ccAddresses == null
? Collections.emptyList() : Arrays.asList(ccAddresses));

// other necessary code

return mailObject;
}


I've thought of doing something like this:



// psuedocode that obviously doesn't compile
Optional.ofNullable(ccAddresses).SOMETHING.orElse(Collections.emptyList());


where SOMETHING would be along the lines of:



Arrays.stream(ints).collect(Collectors.toList());


but I can't seem to get the syntax quite right.



This question was helpful but didn't exactly address my issue. Could anyone point me in the right direction? I feel like I'm close...



Thank you very much for your time.










share|improve this question
















I'm looking for a succinct way to rewrite a piece of Java code so that it uses streams to convert an array to a list in a null-safe fashion. Here's the original code:



public MailObject toMailObject(final String[] ccAddresses) {
final MailObject mailObject = new MailObject();

// line of code to be altered
mailObject.setCcAddresses(ccAddresses == null
? Collections.emptyList() : Arrays.asList(ccAddresses));

// other necessary code

return mailObject;
}


I've thought of doing something like this:



// psuedocode that obviously doesn't compile
Optional.ofNullable(ccAddresses).SOMETHING.orElse(Collections.emptyList());


where SOMETHING would be along the lines of:



Arrays.stream(ints).collect(Collectors.toList());


but I can't seem to get the syntax quite right.



This question was helpful but didn't exactly address my issue. Could anyone point me in the right direction? I feel like I'm close...



Thank you very much for your time.







java java-stream






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 3 hours ago







risingTide

















asked 4 hours ago









risingTiderisingTide

60841238




60841238








  • 3





    Your original code seems succinct enough

    – GBlodgett
    4 hours ago











  • Fair enough, but I'm curious as to the best way it can be done using streams.

    – risingTide
    4 hours ago






  • 1





    .map(Arrays::asList)

    – shmosel
    4 hours ago














  • 3





    Your original code seems succinct enough

    – GBlodgett
    4 hours ago











  • Fair enough, but I'm curious as to the best way it can be done using streams.

    – risingTide
    4 hours ago






  • 1





    .map(Arrays::asList)

    – shmosel
    4 hours ago








3




3





Your original code seems succinct enough

– GBlodgett
4 hours ago





Your original code seems succinct enough

– GBlodgett
4 hours ago













Fair enough, but I'm curious as to the best way it can be done using streams.

– risingTide
4 hours ago





Fair enough, but I'm curious as to the best way it can be done using streams.

– risingTide
4 hours ago




1




1





.map(Arrays::asList)

– shmosel
4 hours ago





.map(Arrays::asList)

– shmosel
4 hours ago












2 Answers
2






active

oldest

votes


















6














You might use the map :



List<String> ccAddrs = Optional.ofNullable(ccAddress)
.map(Arrays::asList)
.orElse(Collections.emptyList())





share|improve this answer



















  • 2





    @downvoter: Should let me know the reason :)

    – Mạnh Quyết Nguyễn
    4 hours ago











  • They don't . Because they are random clickers

    – soorapadman
    2 hours ago



















4














In my opinion, the code that you have so far is perfectly readable. I think using a Stream for something like this will just complicate things. If you still want to use a Stream, then something like the following would work:



mailObject.setCcAddresses(Stream.ofNullable(ccAddresses)
.flatMap(Arrays::stream)
.collect(Collectors.toUnmodifiableList()));


As you can see, this is a more unreadable, and I wouldn't recommend it over your simple ternary expression.





Your Optional solution is slightly more readable and would look like the following:



mailObject.setCcAddresses(Optional.ofNullable(ccAddresses)
.map(Arrays::asList)
.orElse(Collections.emptyList()));





share|improve this answer

























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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    6














    You might use the map :



    List<String> ccAddrs = Optional.ofNullable(ccAddress)
    .map(Arrays::asList)
    .orElse(Collections.emptyList())





    share|improve this answer



















    • 2





      @downvoter: Should let me know the reason :)

      – Mạnh Quyết Nguyễn
      4 hours ago











    • They don't . Because they are random clickers

      – soorapadman
      2 hours ago
















    6














    You might use the map :



    List<String> ccAddrs = Optional.ofNullable(ccAddress)
    .map(Arrays::asList)
    .orElse(Collections.emptyList())





    share|improve this answer



















    • 2





      @downvoter: Should let me know the reason :)

      – Mạnh Quyết Nguyễn
      4 hours ago











    • They don't . Because they are random clickers

      – soorapadman
      2 hours ago














    6












    6








    6







    You might use the map :



    List<String> ccAddrs = Optional.ofNullable(ccAddress)
    .map(Arrays::asList)
    .orElse(Collections.emptyList())





    share|improve this answer













    You might use the map :



    List<String> ccAddrs = Optional.ofNullable(ccAddress)
    .map(Arrays::asList)
    .orElse(Collections.emptyList())






    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 4 hours ago









    Mạnh Quyết NguyễnMạnh Quyết Nguyễn

    11k1930




    11k1930








    • 2





      @downvoter: Should let me know the reason :)

      – Mạnh Quyết Nguyễn
      4 hours ago











    • They don't . Because they are random clickers

      – soorapadman
      2 hours ago














    • 2





      @downvoter: Should let me know the reason :)

      – Mạnh Quyết Nguyễn
      4 hours ago











    • They don't . Because they are random clickers

      – soorapadman
      2 hours ago








    2




    2





    @downvoter: Should let me know the reason :)

    – Mạnh Quyết Nguyễn
    4 hours ago





    @downvoter: Should let me know the reason :)

    – Mạnh Quyết Nguyễn
    4 hours ago













    They don't . Because they are random clickers

    – soorapadman
    2 hours ago





    They don't . Because they are random clickers

    – soorapadman
    2 hours ago













    4














    In my opinion, the code that you have so far is perfectly readable. I think using a Stream for something like this will just complicate things. If you still want to use a Stream, then something like the following would work:



    mailObject.setCcAddresses(Stream.ofNullable(ccAddresses)
    .flatMap(Arrays::stream)
    .collect(Collectors.toUnmodifiableList()));


    As you can see, this is a more unreadable, and I wouldn't recommend it over your simple ternary expression.





    Your Optional solution is slightly more readable and would look like the following:



    mailObject.setCcAddresses(Optional.ofNullable(ccAddresses)
    .map(Arrays::asList)
    .orElse(Collections.emptyList()));





    share|improve this answer






























      4














      In my opinion, the code that you have so far is perfectly readable. I think using a Stream for something like this will just complicate things. If you still want to use a Stream, then something like the following would work:



      mailObject.setCcAddresses(Stream.ofNullable(ccAddresses)
      .flatMap(Arrays::stream)
      .collect(Collectors.toUnmodifiableList()));


      As you can see, this is a more unreadable, and I wouldn't recommend it over your simple ternary expression.





      Your Optional solution is slightly more readable and would look like the following:



      mailObject.setCcAddresses(Optional.ofNullable(ccAddresses)
      .map(Arrays::asList)
      .orElse(Collections.emptyList()));





      share|improve this answer




























        4












        4








        4







        In my opinion, the code that you have so far is perfectly readable. I think using a Stream for something like this will just complicate things. If you still want to use a Stream, then something like the following would work:



        mailObject.setCcAddresses(Stream.ofNullable(ccAddresses)
        .flatMap(Arrays::stream)
        .collect(Collectors.toUnmodifiableList()));


        As you can see, this is a more unreadable, and I wouldn't recommend it over your simple ternary expression.





        Your Optional solution is slightly more readable and would look like the following:



        mailObject.setCcAddresses(Optional.ofNullable(ccAddresses)
        .map(Arrays::asList)
        .orElse(Collections.emptyList()));





        share|improve this answer















        In my opinion, the code that you have so far is perfectly readable. I think using a Stream for something like this will just complicate things. If you still want to use a Stream, then something like the following would work:



        mailObject.setCcAddresses(Stream.ofNullable(ccAddresses)
        .flatMap(Arrays::stream)
        .collect(Collectors.toUnmodifiableList()));


        As you can see, this is a more unreadable, and I wouldn't recommend it over your simple ternary expression.





        Your Optional solution is slightly more readable and would look like the following:



        mailObject.setCcAddresses(Optional.ofNullable(ccAddresses)
        .map(Arrays::asList)
        .orElse(Collections.emptyList()));






        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited 4 hours ago

























        answered 4 hours ago









        Jacob G.Jacob G.

        16.3k52363




        16.3k52363






























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