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Java 8 How to return from a method if Optional is not present?

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2

I don't means return a Optional value, I mean for a method:

public void someMethod() 
 Optional<Obj> obj = someService.getObj();
 if (obj.isPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 
 xxxxxxxxxxxxxxxxxx
 xxxxxxxxxxxxx
 other codes

Is is possible to write it with Optional.ifPresent way? I mean, avoid to use the if isPresent thing.

Many thanks.

== updated:

it seems ifPresentOrElse in JDK9 can do this, but is there any way to do this in JAVA8?

I don't need this method return any value, but if the Optional not present, I want to log something.

java lambda optional

share|improve this question

edited Mar 28 at 14:19

Niuhuru Lang

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  If you want to return if the Optional isn't present, the if/else statement looks good to me. Can't think why you'd want or need to do it another way
  
  – Chris Neve
  Mar 28 at 8:47
  

  
  
  
  

add a comment | 

2

I don't means return a Optional value, I mean for a method:

public void someMethod() 
 Optional<Obj> obj = someService.getObj();
 if (obj.isPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 
 xxxxxxxxxxxxxxxxxx
 xxxxxxxxxxxxx
 other codes

Is is possible to write it with Optional.ifPresent way? I mean, avoid to use the if isPresent thing.

Many thanks.

== updated:

it seems ifPresentOrElse in JDK9 can do this, but is there any way to do this in JAVA8?

I don't need this method return any value, but if the Optional not present, I want to log something.

java lambda optional

share|improve this question

edited Mar 28 at 14:19

Niuhuru Lang

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  If you want to return if the Optional isn't present, the if/else statement looks good to me. Can't think why you'd want or need to do it another way
  
  – Chris Neve
  Mar 28 at 8:47
  

  
  
  
  

add a comment | 

I don't means return a Optional value, I mean for a method:

public void someMethod() 
 Optional<Obj> obj = someService.getObj();
 if (obj.isPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 
 xxxxxxxxxxxxxxxxxx
 xxxxxxxxxxxxx
 other codes

Is is possible to write it with Optional.ifPresent way? I mean, avoid to use the if isPresent thing.

Many thanks.

== updated:

it seems ifPresentOrElse in JDK9 can do this, but is there any way to do this in JAVA8?

I don't need this method return any value, but if the Optional not present, I want to log something.

java lambda optional

share|improve this question

edited Mar 28 at 14:19

Niuhuru Lang

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

public void someMethod() 
 Optional<Obj> obj = someService.getObj();
 if (obj.isPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 
 xxxxxxxxxxxxxxxxxx
 xxxxxxxxxxxxx
 other codes

share|improve this question

edited Mar 28 at 14:19

Niuhuru Lang

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

share|improve this question

edited Mar 28 at 14:19

Niuhuru Lang

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

asked Mar 28 at 8:44

Niuhuru LangNiuhuru Lang

22511 silver badge1818 bronze badges

3 Answers
3

active

oldest

votes

5

Seems like a use case for ifPresentOrElse as in Java-9 :

obj.ifPresentOrElse(a -> ..., () -> logger.info(xxxx);return; );

share|improve this answer

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Good solution. The return; inside the lambda doesn’t do what you think.
  
  – Ole V.V.
  Mar 28 at 8:51
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @OleV.V. It's not of much use agreed. But not sure what in the current context is the use of return as well!
  
  – Naman
  Mar 28 at 8:53
  
  

  
  
  
  

add a comment | 

2

If you want to do nothing when the Optional is empty, you can use ifPresent:

public void someMethod() 
 someService.getObj().ifPresent (v -> 
 ....
 ); 

share|improve this answer

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  However you can't return the obj, because ifPresent is void method, you can only do something with your object. To return value, use if (obj.isPresent())
  
  – Taavi Kivimaa
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @TaaviKivimaa based on the void method the OP posted, I assumed there's no need to return anything.
  
  – Eran
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  OP's english got me confused there, thought he was trying to return something inside the if statement and set a bad example code with void method.
  
  – Taavi Kivimaa
  Mar 28 at 8:57
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your answer. Sorry I don't need to return any value, but I want to log something if not present.
  
  – Niuhuru Lang
  Mar 28 at 14:20
  

  
  
  
  

add a comment | 

0

Just throwing an idea out there, what about having a method on the service to check if the object is present?
I think that generally you don't want to spread your Optionals all over your code, I'd prefer to keep it inside the service.

On SomeService:

public boolean isObjectPresent() 
 return getObj().isPresent();

Then

public void someMethod() 
 if (someService.isObjectPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 

This way you don't have to deal with the Optional in your call as you don't really care about its value

NOTE: Also, I'd add that if you have no code after the if blocks, you don't need the return statement.

share|improve this answer

edited Mar 28 at 9:01

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your idea. This is just an example, I have more codes after the if. so I must return if not present. sorry I didn't mention that, I adjusted my question.
  
  – Niuhuru Lang
  Mar 28 at 14:24
  

  
  
  
  

add a comment | 

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5

Seems like a use case for ifPresentOrElse as in Java-9 :

obj.ifPresentOrElse(a -> ..., () -> logger.info(xxxx);return; );

share|improve this answer

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Good solution. The return; inside the lambda doesn’t do what you think.
  
  – Ole V.V.
  Mar 28 at 8:51
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @OleV.V. It's not of much use agreed. But not sure what in the current context is the use of return as well!
  
  – Naman
  Mar 28 at 8:53
  
  

  
  
  
  

add a comment | 

5

Seems like a use case for ifPresentOrElse as in Java-9 :

obj.ifPresentOrElse(a -> ..., () -> logger.info(xxxx);return; );

share|improve this answer

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Good solution. The return; inside the lambda doesn’t do what you think.
  
  – Ole V.V.
  Mar 28 at 8:51
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @OleV.V. It's not of much use agreed. But not sure what in the current context is the use of return as well!
  
  – Naman
  Mar 28 at 8:53
  
  

  
  
  
  

add a comment | 

Seems like a use case for ifPresentOrElse as in Java-9 :

obj.ifPresentOrElse(a -> ..., () -> logger.info(xxxx);return; );

share|improve this answer

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

obj.ifPresentOrElse(a -> ..., () -> logger.info(xxxx);return; );

share|improve this answer

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

answered Mar 28 at 8:50

NamanNaman

51.9k1414 gold badges111111 silver badges216216 bronze badges

2

If you want to do nothing when the Optional is empty, you can use ifPresent:

public void someMethod() 
 someService.getObj().ifPresent (v -> 
 ....
 ); 

share|improve this answer

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  However you can't return the obj, because ifPresent is void method, you can only do something with your object. To return value, use if (obj.isPresent())
  
  – Taavi Kivimaa
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @TaaviKivimaa based on the void method the OP posted, I assumed there's no need to return anything.
  
  – Eran
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  OP's english got me confused there, thought he was trying to return something inside the if statement and set a bad example code with void method.
  
  – Taavi Kivimaa
  Mar 28 at 8:57
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your answer. Sorry I don't need to return any value, but I want to log something if not present.
  
  – Niuhuru Lang
  Mar 28 at 14:20
  

  
  
  
  

add a comment | 

2

If you want to do nothing when the Optional is empty, you can use ifPresent:

public void someMethod() 
 someService.getObj().ifPresent (v -> 
 ....
 ); 

share|improve this answer

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  However you can't return the obj, because ifPresent is void method, you can only do something with your object. To return value, use if (obj.isPresent())
  
  – Taavi Kivimaa
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @TaaviKivimaa based on the void method the OP posted, I assumed there's no need to return anything.
  
  – Eran
  Mar 28 at 8:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  OP's english got me confused there, thought he was trying to return something inside the if statement and set a bad example code with void method.
  
  – Taavi Kivimaa
  Mar 28 at 8:57
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your answer. Sorry I don't need to return any value, but I want to log something if not present.
  
  – Niuhuru Lang
  Mar 28 at 14:20
  

  
  
  
  

add a comment | 

If you want to do nothing when the Optional is empty, you can use ifPresent:

public void someMethod() 
 someService.getObj().ifPresent (v -> 
 ....
 ); 

share|improve this answer

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

public void someMethod() 
 someService.getObj().ifPresent (v -> 
 ....
 ); 

share|improve this answer

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

answered Mar 28 at 8:48

EranEran

308k4040 gold badges520520 silver badges597597 bronze badges

0

Just throwing an idea out there, what about having a method on the service to check if the object is present?
I think that generally you don't want to spread your Optionals all over your code, I'd prefer to keep it inside the service.

On SomeService:

public boolean isObjectPresent() 
 return getObj().isPresent();

Then

public void someMethod() 
 if (someService.isObjectPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 

This way you don't have to deal with the Optional in your call as you don't really care about its value

NOTE: Also, I'd add that if you have no code after the if blocks, you don't need the return statement.

share|improve this answer

edited Mar 28 at 9:01

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your idea. This is just an example, I have more codes after the if. so I must return if not present. sorry I didn't mention that, I adjusted my question.
  
  – Niuhuru Lang
  Mar 28 at 14:24
  

  
  
  
  

add a comment | 

0

Just throwing an idea out there, what about having a method on the service to check if the object is present?
I think that generally you don't want to spread your Optionals all over your code, I'd prefer to keep it inside the service.

On SomeService:

public boolean isObjectPresent() 
 return getObj().isPresent();

Then

public void someMethod() 
 if (someService.isObjectPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 

This way you don't have to deal with the Optional in your call as you don't really care about its value

NOTE: Also, I'd add that if you have no code after the if blocks, you don't need the return statement.

share|improve this answer

edited Mar 28 at 9:01

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for your idea. This is just an example, I have more codes after the if. so I must return if not present. sorry I didn't mention that, I adjusted my question.
  
  – Niuhuru Lang
  Mar 28 at 14:24
  

  
  
  
  

add a comment | 

Just throwing an idea out there, what about having a method on the service to check if the object is present?
I think that generally you don't want to spread your Optionals all over your code, I'd prefer to keep it inside the service.

On SomeService:

public boolean isObjectPresent() 
 return getObj().isPresent();

Then

public void someMethod() 
 if (someService.isObjectPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 

This way you don't have to deal with the Optional in your call as you don't really care about its value

NOTE: Also, I'd add that if you have no code after the if blocks, you don't need the return statement.

share|improve this answer

edited Mar 28 at 9:01

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

public boolean isObjectPresent() 
 return getObj().isPresent();

public void someMethod() 
 if (someService.isObjectPresent()) 
 ....
 else 
 log.info(xxxx);
 return;
 

share|improve this answer

edited Mar 28 at 9:01

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges

answered Mar 28 at 8:55

BentayeBentaye

5,53233 gold badges2323 silver badges3333 bronze badges