CODEWITHSUNDEEP
javajava-8java-stream
DarkCrow
DarkCrow

Reputation: 850

How do we handle exception in java streams

How can I convert this for loop using the stream.

for (final Foo foo : fooList) {
    if (!FooConstant.FOO_TYPE.equals(foo.getType())) {
        throw new BadRequestException(
          LOGGER,
          FooErrorEnum.NOT_FOO_TYPE.name(),
          String.format("Element %s is not Foo type", foo.getId())
        );
    }
}

I tried doing this way but the foo.getId() is not available in orElseThrow(). Note: BadRequestException is checked exception.

fooList.stream().filter(foo -> !FooConstant.FOO_TYPE.equals(foo.getType())
    .findFirst()
    .orElseThrow(() -> new BadRequestException(LOGGER, FooErrorEnum.NOT_FOO_TYPE.name(), String.format("Element %s is not Foo type", foo.getId()));

Upvotes: 3

Views: 161

Answers (1)

Andrew
Andrew

Reputation: 49606

You need Optional#ifPresent.

fooList.stream().filter(foo -> !FooConstant.FOO_TYPE.equals(foo.getType())
                .findFirst()
                .ifPresent(foo -> {
                     throw new BadRequestException(LOGGER, FooErrorEnum.NOT_FOO_TYPE.name(), String.format("Element %s is not Foo type", foo.getId())
                });

It's weird, though. We usually use Optional the other way around: to filter out invalid options and find the first valid one. In your example, orElseThrow would be executed when everything is fine, so no exception should be thrown.

Note that BadRequestException must be a RuntimeException, otherwise it won't compile.

Upvotes: 3

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