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Alternative approach for checking data types to build an object

发布于 2020-11-28 00:40:23

I'm trying to build an object, which uses different methods based on different data types. I.e. it differs from withBooleanValue,withStringValue and withDateValue depending on the data type. What I have is a string, and depending on what that string is (boolean, string or date), I need to build this object. Below is how I went about it.

private List<Answer> getAnswers(Set<Question> questions) {
        List<Answer> answers = new ArrayList<>();
        questions.forEach(question -> {
            Answer.Builder answer = Answer.builder()
                    .withQuestion(question.question());
            if (BooleanUtils.toBooleanObject(question.value()) != null) {
                answer.withValue(AnswerValue.builder()
                        .withBooleanValue(BooleanUtils.toBoolean(question.value()))
                        .build());
            } else {
                try {
                    Date dateValue = DateUtils.parseDate(question.value(), new String[]{"dd-MM-YYYY"});
                    answer.withValue(AnswerValue.builder()
                            .withDateValue(dateValue)
                            .build());

                } catch (ParseException e) {
                    answer.withValue(AnswerValue.builder()
                            .withStringValue(question.value())
                            .build());
                }
            }
            answers.add(answer.build());
        });
        return answers;
    }

Is there a better way to do this in Java8? Somehow the ifs, and try-catch statements make it look very complicated and I'd like to reduce the lines and complexity with a better way. Any advice would be much appreciated.

Questioner
AnOldSoul
Viewed
0
Vlad L 2020-11-28 09:52:09

In terms of just refactoring the code, I would start with something like this (it doesn't compile since I don't have all the classes, so may have some errors):

    private List<Answer> getAnswers(Set<Question> questions) {
        List<Answer> answers = new ArrayList<>();
        questions.forEach(question -> {
            Answer.Builder answer = Answer.builder()
                    .withQuestion(question.question())
                    .withValue(parseAnswerValue(question));

            answers.add(answer.build());
        });
        return answers;
    }

    private AnswerValue parseAnswerValue(Question question) {
        Optional<AnswerValue> answerOptional = parseBoolean(question);
        if (answerOptional.isEmpty()) {
            answerOptional = parseDate(question);
        }

        return answerOptional.isEmpty() ? parseString(question) : answerOptional.get();
    }

    private Optional<AnswerValue> parseBoolean(Question question) {
        if (BooleanUtils.toBooleanObject(question.value()) != null) {
            return Optional.of(AnswerValue.builder()
                    .withBooleanValue(BooleanUtils.toBoolean(question.value()))
                    .build());
        }
        return Optional.empty();
    }

    private Optional<AnswerValue> parseDate(Question question) {
        try {
            Date dateValue = DateUtils.parseDate(question.value(), new String[]{"dd-MM-YYYY"});
            return Optional.of(AnswerValue.builder()
                    .withDateValue(dateValue)
                    .build());

        } catch (ParseException e) {
            return Optional.empty();
        }
    }


    private AnswerValue parseString(Question question) {
        return AnswerValue.builder()
                .withStringValue(question.value())
                .build();
    }

Then something like this. Also it would require having a global date, which may be questionable. Also instead of passing question around, it's possible to pass question.value() instead.

    private List<Answer> getAnswers(Set<Question> questions) {
        List<Answer> answers = new ArrayList<>();
        questions.forEach(question -> {
            Answer.Builder answer = Answer.builder()
                    .withQuestion(question.question())
                    .withValue(parseAnswerValue(question));

            answers.add(answer.build());
        });
        return answers;
    }

    private AnswerValue parseAnswerValue(Question question) {
        AnswerValue.Builder answerBuilder = AnswerValue.builder();
        
        if (isBoolean(question)) {
            answerBuilder.withBooleanValue(BooleanUtils.toBoolean(question.value()));
        } else if (isDate(question)) {
            answerBuilder.withDateValue(dateValue);
        } else {
            answerBuilder.withStringValue(question.value());
        }

        return answerBuilder.build();
    }

    private boolean isBoolean(Question question) {
        return BooleanUtils.toBooleanObject(question.value()) != null;
    }

    private boolean isDate(Question question) {
        try {
            dateValue = DateUtils.parseDate(question.value(), new String[]{"dd-MM-YYYY"});
            return true;
        } catch (ParseException e) {
            return false;
        }
    }