error: incompatible types: unexpected return value : Java 8 [duplicate]
up vote
7
down vote
favorite
2
This question already has an answer here:
error: incompatible types: unexpected return value Char compare to String
3 answers
I have written a simple method which returns the boolean value.
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null)
{
studentConfigs.forEach(studentConfig -> {
if(studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE)) {
return true;
}
});
}
return false;
}
The method is throwing the following exception .
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
What's the problem with my code?
java foreach java-8 java-stream
edited 13 hours ago
Andrew Tobilko
23.9k84078
asked 14 hours ago
Ram R
413
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Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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marked as duplicate by Robert Harvey♦ 10 hours ago
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
up vote
7
down vote
favorite
2
This question already has an answer here:
error: incompatible types: unexpected return value Char compare to String
3 answers
I have written a simple method which returns the boolean value.
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null)
{
studentConfigs.forEach(studentConfig -> {
if(studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE)) {
return true;
}
});
}
return false;
}
The method is throwing the following exception .
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
What's the problem with my code?
java foreach java-8 java-stream
edited 13 hours ago
Andrew Tobilko
23.9k84078
asked 14 hours ago
Ram R
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
marked as duplicate by Robert Harvey♦ 10 hours ago
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
up vote
7
down vote
favorite
2
up vote
7
down vote
favorite
2
2
This question already has an answer here:
error: incompatible types: unexpected return value Char compare to String
3 answers
I have written a simple method which returns the boolean value.
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null)
{
studentConfigs.forEach(studentConfig -> {
if(studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE)) {
return true;
}
});
}
return false;
}
The method is throwing the following exception .
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
What's the problem with my code?
java foreach java-8 java-stream
edited 13 hours ago
Andrew Tobilko
23.9k84078
asked 14 hours ago
Ram R
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This question already has an answer here:
error: incompatible types: unexpected return value Char compare to String
3 answers
I have written a simple method which returns the boolean value.
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null)
{
studentConfigs.forEach(studentConfig -> {
if(studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE)) {
return true;
}
});
}
return false;
}
The method is throwing the following exception .
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
What's the problem with my code?
This question already has an answer here:
error: incompatible types: unexpected return value Char compare to String
3 answers
java foreach java-8 java-stream
java foreach java-8 java-stream
edited 13 hours ago
Andrew Tobilko
23.9k84078
asked 14 hours ago
Ram R
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 13 hours ago
Andrew Tobilko
23.9k84078
asked 14 hours ago
Ram R
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 13 hours ago
Andrew Tobilko
23.9k84078
edited 13 hours ago
Andrew Tobilko
23.9k84078
edited 13 hours ago
Andrew Tobilko
23.9k84078
23.9k84078
asked 14 hours ago
Ram R
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 14 hours ago
Ram R
413
asked 14 hours ago
Ram R
413
413
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Ram R is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
marked as duplicate by Robert Harvey♦ 10 hours ago
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
marked as duplicate by Robert Harvey♦ 10 hours ago
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
add a comment |
5 Answers
5
active
oldest
votes
up vote
9
down vote
accepted
The lambda expression passed to forEach shouldn't have a return value.
It looks like you want to return true if any of the elements of the input Collection satisfies a condition:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null) {
if (studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE))) {
return true;
}
}
return false;
}
As Holger suggested, this can be reduced to a single statement:
return studentConfigs != null && studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE));
or
return studentConfigs != null ? studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE)) : false;
answered 14 hours ago
Eran
273k35434518
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think usinganyMatchin this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.
– Eran
14 hours ago
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
@LukeGarrigan well, you would usecollection.contains(obj)instead of looping over the collection to test each element for equality, wouldn’t you? Socollection.stream().anyMatch(condition)is just a generalization of the idea, when the condition is more complex than plain equality.
– Holger
11 hours ago
|
show 2 more comments
up vote
4
down vote
Alternatively with Java9 and above you can use Stream.ofNullable and update as:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs) {
return Stream.ofNullable(studentConfigs)
.flatMap(Collection::stream)
.anyMatch(studentConfig -> studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE));
}
answered 14 hours ago
nullpointer
35.5k1071141
4
It’s debatable whetherStream.ofNullable(studentConfigs) .flatMap(Collection::stream) …is simpler thanstudentConfigs != null && studentConfigs.stream() …
– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue withflatMapwhich still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.
– Holger
13 hours ago
add a comment |
up vote
4
down vote
I don't recommend you use Stream API here. Look at how clear and simple the foreach version is:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigurations) {
if(studentConfigurations == null) {
return false;
}
for (StudentConfiguration configuration : studentConfigurations) {
if (!Action.DELETE.equals(configuration.action())) {
return true;
}
}
return false;
}
Otherwise, if you are a fanatic guy,
private boolean isActionAvailable(Collection<StudentConfiguration> configs) {
return configs != null &&
configs.stream()
.map(StudentConfiguration::action)
.anyMatch(Predicate.isEqual(Action.DELETE).negate()));
}
answered 13 hours ago
Andrew Tobilko
23.9k84078
add a comment |
up vote
1
down vote
The return statement in your lambda will terminate that lambda, not the isActionAvailable() method. Therefore, the inferred type of the lambda is now wrong, because forEach expects a Consumer.
See the other answers for how to solve that problem.
answered 13 hours ago
ohlec
1,685717
add a comment |
up vote
0
down vote
This is signature of forEach() method forEach(Consumer<? super T> action) .
It takes reference of Consumer interface which has method void accept(T t).
In your code you are overriding accept() and returning a value which is not valid as accept() has void return type.
Therefore it is showing error
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
answered 13 hours ago
Tarun
601414
add a comment |
5 Answers
5
active
oldest
votes
5 Answers
5
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
9
down vote
accepted
The lambda expression passed to forEach shouldn't have a return value.
It looks like you want to return true if any of the elements of the input Collection satisfies a condition:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null) {
if (studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE))) {
return true;
}
}
return false;
}
As Holger suggested, this can be reduced to a single statement:
return studentConfigs != null && studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE));
or
return studentConfigs != null ? studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE)) : false;
answered 14 hours ago
Eran
273k35434518
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think usinganyMatchin this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.
– Eran
14 hours ago
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
@LukeGarrigan well, you would usecollection.contains(obj)instead of looping over the collection to test each element for equality, wouldn’t you? Socollection.stream().anyMatch(condition)is just a generalization of the idea, when the condition is more complex than plain equality.
– Holger
11 hours ago
|
show 2 more comments
up vote
9
down vote
accepted
The lambda expression passed to forEach shouldn't have a return value.
It looks like you want to return true if any of the elements of the input Collection satisfies a condition:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null) {
if (studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE))) {
return true;
}
}
return false;
}
As Holger suggested, this can be reduced to a single statement:
return studentConfigs != null && studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE));
or
return studentConfigs != null ? studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE)) : false;
answered 14 hours ago
Eran
273k35434518
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think usinganyMatchin this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.
– Eran
14 hours ago
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
@LukeGarrigan well, you would usecollection.contains(obj)instead of looping over the collection to test each element for equality, wouldn’t you? Socollection.stream().anyMatch(condition)is just a generalization of the idea, when the condition is more complex than plain equality.
– Holger
11 hours ago
|
show 2 more comments
up vote
9
down vote
accepted
up vote
9
down vote
accepted
The lambda expression passed to forEach shouldn't have a return value.
It looks like you want to return true if any of the elements of the input Collection satisfies a condition:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null) {
if (studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE))) {
return true;
}
}
return false;
}
As Holger suggested, this can be reduced to a single statement:
return studentConfigs != null && studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE));
or
return studentConfigs != null ? studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE)) : false;
answered 14 hours ago
Eran
273k35434518
The lambda expression passed to forEach shouldn't have a return value.
It looks like you want to return true if any of the elements of the input Collection satisfies a condition:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs){
if(studentConfigs != null) {
if (studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE))) {
return true;
}
}
return false;
}
As Holger suggested, this can be reduced to a single statement:
return studentConfigs != null && studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE));
or
return studentConfigs != null ? studentConfigs.stream().anyMatch(sc -> sc.action() == null || !sc.action().equals(Action.DELETE)) : false;
answered 14 hours ago
Eran
273k35434518
edited 13 hours ago
answered 14 hours ago
Eran
273k35434518
answered 14 hours ago
Eran
273k35434518
answered 14 hours ago
Eran
273k35434518
273k35434518
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think usinganyMatchin this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.
– Eran
14 hours ago
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
@LukeGarrigan well, you would usecollection.contains(obj)instead of looping over the collection to test each element for equality, wouldn’t you? Socollection.stream().anyMatch(condition)is just a generalization of the idea, when the condition is more complex than plain equality.
– Holger
11 hours ago
|
show 2 more comments
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think usinganyMatchin this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.
– Eran
14 hours ago
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
@LukeGarrigan well, you would usecollection.contains(obj)instead of looping over the collection to test each element for equality, wouldn’t you? Socollection.stream().anyMatch(condition)is just a generalization of the idea, when the condition is more complex than plain equality.
– Holger
11 hours ago
2
2
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
Why not a simple enhanced forloop? When do you choose one over the other?
– Luke Garrigan
14 hours ago
1
1
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think using
anyMatch in this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.– Eran
14 hours ago
@LukeGarrigan Enhanced for loop would also be fine. As to which one to choose, I'd go for the one more readable to you (and to other developers that may read your code). I think using
anyMatch in this example better expresses what the method is doing, which is to find whether any of the elements of the input collection satisfies some condition.– Eran
14 hours ago
1
1
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
@LukeGarrigan Java is an evolving language. Higher order functions are working their way in. I would suggest you embrace them, rather than get left behind
– Alexander
12 hours ago
1
1
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
@LukeGarrigan "I suppose it's just because I don't use it as often as I potentially should." Yep, pretty much. This is the future of Java, so you'll only see more and more of these higher order functions.
– Alexander
11 hours ago
1
1
@LukeGarrigan well, you would use
collection.contains(obj) instead of looping over the collection to test each element for equality, wouldn’t you? So collection.stream().anyMatch(condition) is just a generalization of the idea, when the condition is more complex than plain equality.– Holger
11 hours ago
@LukeGarrigan well, you would use
collection.contains(obj) instead of looping over the collection to test each element for equality, wouldn’t you? So collection.stream().anyMatch(condition) is just a generalization of the idea, when the condition is more complex than plain equality.– Holger
11 hours ago
|
show 2 more comments
up vote
4
down vote
Alternatively with Java9 and above you can use Stream.ofNullable and update as:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs) {
return Stream.ofNullable(studentConfigs)
.flatMap(Collection::stream)
.anyMatch(studentConfig -> studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE));
}
answered 14 hours ago
nullpointer
35.5k1071141
4
It’s debatable whetherStream.ofNullable(studentConfigs) .flatMap(Collection::stream) …is simpler thanstudentConfigs != null && studentConfigs.stream() …
– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue withflatMapwhich still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.
– Holger
13 hours ago
add a comment |
up vote
4
down vote
Alternatively with Java9 and above you can use Stream.ofNullable and update as:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs) {
return Stream.ofNullable(studentConfigs)
.flatMap(Collection::stream)
.anyMatch(studentConfig -> studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE));
}
answered 14 hours ago
nullpointer
35.5k1071141
4
It’s debatable whetherStream.ofNullable(studentConfigs) .flatMap(Collection::stream) …is simpler thanstudentConfigs != null && studentConfigs.stream() …
– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue withflatMapwhich still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.
– Holger
13 hours ago
add a comment |
up vote
4
down vote
up vote
4
down vote
Alternatively with Java9 and above you can use Stream.ofNullable and update as:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs) {
return Stream.ofNullable(studentConfigs)
.flatMap(Collection::stream)
.anyMatch(studentConfig -> studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE));
}
answered 14 hours ago
nullpointer
35.5k1071141
Alternatively with Java9 and above you can use Stream.ofNullable and update as:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigs) {
return Stream.ofNullable(studentConfigs)
.flatMap(Collection::stream)
.anyMatch(studentConfig -> studentConfig.action() == null || !studentConfig.action().equals(Action.DELETE));
}
answered 14 hours ago
nullpointer
35.5k1071141
answered 14 hours ago
nullpointer
35.5k1071141
answered 14 hours ago
nullpointer
35.5k1071141
answered 14 hours ago
nullpointer
35.5k1071141
35.5k1071141
4
It’s debatable whetherStream.ofNullable(studentConfigs) .flatMap(Collection::stream) …is simpler thanstudentConfigs != null && studentConfigs.stream() …
– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue withflatMapwhich still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.
– Holger
13 hours ago
add a comment |
4
It’s debatable whetherStream.ofNullable(studentConfigs) .flatMap(Collection::stream) …is simpler thanstudentConfigs != null && studentConfigs.stream() …
– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue withflatMapwhich still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.
– Holger
13 hours ago
4
4
It’s debatable whether
Stream.ofNullable(studentConfigs) .flatMap(Collection::stream) … is simpler than studentConfigs != null && studentConfigs.stream() …– Holger
13 hours ago
It’s debatable whether
Stream.ofNullable(studentConfigs) .flatMap(Collection::stream) … is simpler than studentConfigs != null && studentConfigs.stream() …– Holger
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
@Holger By simpler here you meant readability aspect or performance as well? Readability I believe would be opinion based, I find it easy to read now, maybe sometimes back I wouldn't have.
– nullpointer
13 hours ago
2
2
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue with
flatMap which still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.– Holger
13 hours ago
I only meant readability when I wrote the comment, but now that you’re asking… There is the lack-of-laziness issue with
flatMap which still exists in Java 9, which would be a reason not to use your variant before Java 10. But in recent versions, I wouldn’t think about any remaining minor performance differences.– Holger
13 hours ago
add a comment |
up vote
4
down vote
I don't recommend you use Stream API here. Look at how clear and simple the foreach version is:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigurations) {
if(studentConfigurations == null) {
return false;
}
for (StudentConfiguration configuration : studentConfigurations) {
if (!Action.DELETE.equals(configuration.action())) {
return true;
}
}
return false;
}
Otherwise, if you are a fanatic guy,
private boolean isActionAvailable(Collection<StudentConfiguration> configs) {
return configs != null &&
configs.stream()
.map(StudentConfiguration::action)
.anyMatch(Predicate.isEqual(Action.DELETE).negate()));
}
answered 13 hours ago
Andrew Tobilko
23.9k84078
add a comment |
up vote
4
down vote
I don't recommend you use Stream API here. Look at how clear and simple the foreach version is:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigurations) {
if(studentConfigurations == null) {
return false;
}
for (StudentConfiguration configuration : studentConfigurations) {
if (!Action.DELETE.equals(configuration.action())) {
return true;
}
}
return false;
}
Otherwise, if you are a fanatic guy,
private boolean isActionAvailable(Collection<StudentConfiguration> configs) {
return configs != null &&
configs.stream()
.map(StudentConfiguration::action)
.anyMatch(Predicate.isEqual(Action.DELETE).negate()));
}
answered 13 hours ago
Andrew Tobilko
23.9k84078
add a comment |
up vote
4
down vote
up vote
4
down vote
I don't recommend you use Stream API here. Look at how clear and simple the foreach version is:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigurations) {
if(studentConfigurations == null) {
return false;
}
for (StudentConfiguration configuration : studentConfigurations) {
if (!Action.DELETE.equals(configuration.action())) {
return true;
}
}
return false;
}
Otherwise, if you are a fanatic guy,
private boolean isActionAvailable(Collection<StudentConfiguration> configs) {
return configs != null &&
configs.stream()
.map(StudentConfiguration::action)
.anyMatch(Predicate.isEqual(Action.DELETE).negate()));
}
answered 13 hours ago
Andrew Tobilko
23.9k84078
I don't recommend you use Stream API here. Look at how clear and simple the foreach version is:
private boolean isActionAvailable(Collection<StudentConfiguration> studentConfigurations) {
if(studentConfigurations == null) {
return false;
}
for (StudentConfiguration configuration : studentConfigurations) {
if (!Action.DELETE.equals(configuration.action())) {
return true;
}
}
return false;
}
Otherwise, if you are a fanatic guy,
private boolean isActionAvailable(Collection<StudentConfiguration> configs) {
return configs != null &&
configs.stream()
.map(StudentConfiguration::action)
.anyMatch(Predicate.isEqual(Action.DELETE).negate()));
}
answered 13 hours ago
Andrew Tobilko
23.9k84078
edited 13 hours ago
answered 13 hours ago
Andrew Tobilko
23.9k84078
answered 13 hours ago
Andrew Tobilko
23.9k84078
answered 13 hours ago
Andrew Tobilko
23.9k84078
23.9k84078
add a comment |
add a comment |
up vote
1
down vote
The return statement in your lambda will terminate that lambda, not the isActionAvailable() method. Therefore, the inferred type of the lambda is now wrong, because forEach expects a Consumer.
See the other answers for how to solve that problem.
answered 13 hours ago
ohlec
1,685717
add a comment |
up vote
1
down vote
The return statement in your lambda will terminate that lambda, not the isActionAvailable() method. Therefore, the inferred type of the lambda is now wrong, because forEach expects a Consumer.
See the other answers for how to solve that problem.
answered 13 hours ago
ohlec
1,685717
add a comment |
up vote
1
down vote
up vote
1
down vote
The return statement in your lambda will terminate that lambda, not the isActionAvailable() method. Therefore, the inferred type of the lambda is now wrong, because forEach expects a Consumer.
See the other answers for how to solve that problem.
answered 13 hours ago
ohlec
1,685717
The return statement in your lambda will terminate that lambda, not the isActionAvailable() method. Therefore, the inferred type of the lambda is now wrong, because forEach expects a Consumer.
See the other answers for how to solve that problem.
answered 13 hours ago
ohlec
1,685717
answered 13 hours ago
ohlec
1,685717
answered 13 hours ago
ohlec
1,685717
answered 13 hours ago
ohlec
1,685717
1,685717
add a comment |
add a comment |
up vote
0
down vote
This is signature of forEach() method forEach(Consumer<? super T> action) .
It takes reference of Consumer interface which has method void accept(T t).
In your code you are overriding accept() and returning a value which is not valid as accept() has void return type.
Therefore it is showing error
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
answered 13 hours ago
Tarun
601414
add a comment |
up vote
0
down vote
This is signature of forEach() method forEach(Consumer<? super T> action) .
It takes reference of Consumer interface which has method void accept(T t).
In your code you are overriding accept() and returning a value which is not valid as accept() has void return type.
Therefore it is showing error
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
answered 13 hours ago
Tarun
601414
add a comment |
up vote
0
down vote
up vote
0
down vote
This is signature of forEach() method forEach(Consumer<? super T> action) .
It takes reference of Consumer interface which has method void accept(T t).
In your code you are overriding accept() and returning a value which is not valid as accept() has void return type.
Therefore it is showing error
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
answered 13 hours ago
Tarun
601414
This is signature of forEach() method forEach(Consumer<? super T> action) .
It takes reference of Consumer interface which has method void accept(T t).
In your code you are overriding accept() and returning a value which is not valid as accept() has void return type.
Therefore it is showing error
error: incompatible types: unexpected return value
studentConfigs.forEach(studentConfig ->
answered 13 hours ago
Tarun
601414
answered 13 hours ago
Tarun
601414
answered 13 hours ago
Tarun
601414
answered 13 hours ago
Tarun
601414
601414
add a comment |
add a comment |
