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












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.






java java-stream







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.






java java-stream







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.






java java-stream







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




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 5 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































    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




























        6














        You might use the map :



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





        share|improve this answer


























          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

























              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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