Gdtyjr

Why Shazam when there is already Superman?

Pre-Employment Background Check With Consent For Future Checks

I'm just a whisper. Who am I?

Can I run 125kHz RF circuit on a breadboard?

Mimic lecturing on blackboard, facing audience

Proving an identity involving cross products and coplanar vectors

Should I warn new/prospective PhD Student that supervisor is terrible?

How to preserve electronics (computers, iPads and phones) for hundreds of years

Personal or impersonal in a technical resume

In One Punch Man, is King actually weak?

What does "Scientists rise up against statistical significance" mean? (Comment in Nature)

If the only attacker is removed from combat, is a creature still counted as having attacked this turn?

Quoting Keynes in a lecture

Unable to disable Microsoft Store in domain environment

What is this high flying aircraft over Pennsylvania?

How can I safely use "Thalidomide" in my novel while respecting the trademark?

Can I say "fingers" when referring to toes?

Typing CO_2 easily

How were servants to the Kaiser of Imperial Germany treated and where may I find more information on them

Is there a RAID 0 Equivalent for RAM?

How to get directions in deep space?

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

Grepping string, but include all non-blank lines following each grep match

Language involving irrational number is not a CFL

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

Converting Array to ListCreate ArrayList from arrayHow to simplify a null-safe compareTo() implementation?Converting array to list in JavaConvert list to array in JavaRetrieving a List from a java.util.stream.Stream in Java 8How to Convert a Java 8 Stream to an Array?Java 8 Stream and operation on arraysHow can I create a stream from an array?How to sum a list of integers with java streams?Java 8 stream - how to properly make NPE-safe stream

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

edited 3 hours ago

risingTide

asked 5 hours ago

risingTiderisingTide

60841238

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Your original code seems succinct enough
  
  – GBlodgett
  5 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
  

  
  
  
  

add a comment | 

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

edited 3 hours ago

risingTide

asked 5 hours ago

risingTiderisingTide

60841238

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Your original code seems succinct enough
  
  – GBlodgett
  5 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
  

  
  
  
  

add a comment | 

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

edited 3 hours ago

risingTide

asked 5 hours ago

risingTiderisingTide

60841238

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;

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

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

share|improve this question

edited 3 hours ago

risingTide

asked 5 hours ago

risingTiderisingTide

60841238

share|improve this question

edited 3 hours ago

risingTide

asked 5 hours ago

risingTiderisingTide

60841238

asked 5 hours ago

risingTiderisingTide

60841238

asked 5 hours ago

risingTiderisingTide

60841238

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

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

add a comment | 

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

edited 4 hours ago

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55272522%2fusing-streams-for-a-null-safe-conversion-from-an-array-to-list%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

6

You might use the map :

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

share|improve this answer

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

add a comment | 

6

You might use the map :

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

share|improve this answer

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

add a comment | 

You might use the map :

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

share|improve this answer

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

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

share|improve this answer

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

11k1930

answered 4 hours ago

Mạnh Quyết NguyễnMạnh Quyết Nguyễn

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

edited 4 hours ago

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

add a comment | 

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

edited 4 hours ago

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

add a comment | 

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

edited 4 hours ago

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

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

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

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363

answered 4 hours ago

Jacob G.Jacob G.

16.3k52363