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gexter
Asked:2022-08-13 18:45:22 +0800 CST2022-08-13 18:45:22 +0800 CST

如何摆脱枚举类？

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public class ReportBuilder {
private final DataParser parser = new DataParser();
private final DataReader reader = new DataReader();
private List<ReportRecord> recordList;

enum EndOrStart {
    END, START
}

public List<String> prepareReport(String startFile, String endFile, String abbrevFile) {
    formatChart(abbrevFile);
    addTime(startFile, EndOrStart.START);
    addTime(endFile, EndOrStart.END);
    recordList.forEach(rec -> rec.setTimeDiff(rec.getEndTime().toNanoOfDay()-rec.getStartTime().toNanoOfDay()));
    sortByDiffTime();
    return collectReport();

}

private Stream<String> recordToString(int index) {
    String timeFormat = "m:ss.SSS";
    String reportFormat = "%d. %s | %s | %s";
    String delimiter = "-".repeat(60);
    ReportRecord dataRecord = recordList.get(index);
    String name = dataRecord.getName();
    String team = dataRecord.getTeam();
    String time = LocalTime.ofNanoOfDay(dataRecord.getTimeDiff()).format(DateTimeFormatter.ofPattern(timeFormat));
    String result = String.format(reportFormat, 1 + index, name, team, time);
    return (1 + index) % 15 == 0
            ? Stream.of(result, delimiter)
            : Stream.of(result);
}

private ArrayList<String> collectReport() {
    return IntStream.range(0, recordList.size())
            .mapToObj(this::recordToString)
            .flatMap(s -> s)
            .collect(Collectors.toCollection(ArrayList::new));
}

private void formatChart(String abbrevFile) {
    List<String> abbrevList = reader.readFile(abbrevFile);
    recordList = new ArrayList<>(abbrevList.size());
    abbrevList.stream().sorted(Comparator.naturalOrder())
            .forEach(line -> recordList.add(parser.parseRacer(line)));
}

private void addTime(String timeFile, EndOrStart startOrEndFile) {
    List<String> timeStringList = reader.readFile(timeFile);
    timeStringList.sort(Comparator.naturalOrder());
    List<LocalTime> timeList = timeStringList.stream().map(parser::parseTime).collect(Collectors.toList());
    if (startOrEndFile.equals(EndOrStart.START)) {
        recordList.forEach(rec -> rec.setStartTime(timeList.get(recordList.indexOf(rec))));
    }
    if (startOrEndFile.equals(EndOrStart.END)) {
        recordList.forEach(rec -> rec.setEndTime(timeList.get(recordList.indexOf(rec))));
    }
}

在 addTime 方法中，我将有关开始时间 (startTime) 和结束时间 (entTime) 的数据添加到 ReportRecord 类的实例中。为了使 addTime 方法具有通用性，我在 prepareReport 方法中调用了两次，并将其作为第二个枚举参数传递，该参数指示我正在为哪个字段赋值。我们如何摆脱枚举类并保持 addTime 方法的通用性？

java

1 个回答

  1. Best Answer

    在最简单的情况下，您可以将 enum 替换为 true/false 标志。一个更美观、更通用的选择是将行为逻辑作为参数传递给方法。

    private void addTime(String timeFile, BiConsumer<ReportRecord, LocalTime> consumer) {
        List<String> timeStringList = reader.readFile(timeFile);
        timeStringList.sort(Comparator.naturalOrder());
        List<LocalTime> timeList = timeStringList.stream().map(parser::parseTime).collect(Collectors.toList());
        recordList.forEach(rec -> consumer.accept(rec, timeList.get(recordList.indexOf(rec))));
    }

    好吧，挑战：

    addTime(startFile, ReportRecord::setStartTime);
addTime(endFile, ReportRecord::setEndTime);
    • 2

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