CODEWITHSUNDEEP
javalombok
Rpj
Rpj

Reputation: 6080

How to add using Singular attribute in lombok

How to add using @Singular attribute in lombok

Foo foo = ..;
FooActivity fa = ..;

foo.fooActivity(fa); // this fails - compilation error

@Builder    
class Foo {
    @Singular("fooActivity")
    private List<FooActivity> fooActivities;
}

Upvotes: 2

Views: 2374

Answers (2)

Gautham M
Gautham M

Reputation: 4935

@Singular is to be used along with @Builder annotation. So in this case the fooActivity method to add an element to the list is created in the FooBuilder class generated by lombok and it is NOT part of Foo. Hence you cannot access fooActivity using the Foo object.

How to solve? (There is an issue with this approach, which I have mentioned in the end.)

You can solve this by having toBuilder set to true for the @Builder annotation. This would generate a method in Foo that would return a builder object, which you can use to invoke fooActivity.

@Builder(toBuilder = true)
public class Foo {
    @Singular("fooActivity")
    private List<FooActivity> acts;
}

// To invoke
foo = foo.toBuilder().fooActivity(fa).build();

The issue with the above approach

toBuilder() would generate a builder using the values in foo and the build would generate a NEW object. So you need to be careful with this because the original object foo is not the one being updated using this approach.

Second Approach (Not recommended)

Use experimental feature @Delegate. This is what the lombok website says about this feature:

Currently we feel this feature will not move out of experimental status anytime soon, and support for this feature may be dropped if future versions of javac or ecj make it difficult to continue to maintain the feature.

It would also cause issues when there are multiple collections in your class.

@Builder
public class Foo {
    @Delegate
    @Builder.Default
    private List<FooActivity> acts = new ArrayList<>(); // make sure you do this while using @Delegate    
}

To invoke

foo.add(fa);

Upvotes: 1

user11868214
user11868214

Reputation:

Have you tried something like this?

Foo myFoo = Foo.builder()
.fooActivity(new FooActivity())
.fooActivity(new FooActivity())
.build();

Upvotes: 2

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