比较器没有正确排序

Question

我正在尝试编写一个测试来强调下一个类的行为。它是网站的比较器，但由于某种原因，“propertiesCreatedBy”部分不起作用。这是一个非常奇怪的问题，只要其余字段正常工作并且可以正确排序，但是当尝试按此列排序时，顺序似乎是随机的：

import java.io.Serializable;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;


public class CaseNoteDTOComparator implements Comparator, Serializable {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    protected class CaseNoteDTOComparatorInternal implements Serializable  {
        private String[] properties = null;
        boolean[] shouldReverse = null;

        public CaseNoteDTOComparatorInternal(String[] properties, boolean[] shouldReverse) {
            this.properties = properties;
            this.shouldReverse = shouldReverse;
        }

        public int compare(Object obj1, Object obj2) {
            int result = 0;
            for (int i = 0; i < properties.length; i++) {
                JavaBeanNamedPropertyComparator comparator =
                    new JavaBeanNamedPropertyComparator(properties[i], shouldReverse[i]);
                result = comparator.compare(obj1, obj2);
                if(result != ComparatorConstants.EQUAL) {
                    return result;
                }
            }
            //actually object are equals....
            return ComparatorConstants.LESS_THAN;
        }

        public void setDescending(boolean descending) {
            for (int i = 0; i < shouldReverse.length; i++) {
                shouldReverse[i] = descending;
            }
        }
    }

    private static Map comparators = new HashMap();

    //statically initialise comparators
    {
        final String[] propertiesEffectiveDate = { EFFECTIVE_DATE_NAME, CREATED_ON };
        boolean[] shouldReverseEffectiveDate= {false, false};
        comparators.put(EFFECTIVE_DATE_NAME, new CaseNoteDTOComparatorInternal(propertiesEffectiveDate, shouldReverseEffectiveDate));

        final String[] propertiesId = { ID_NAME };
        boolean[] shouldReverseId = {false};
        comparators.put(ID_NAME, new CaseNoteDTOComparatorInternal( propertiesId, shouldReverseId));

        final String[] propertiesType = { TYPE_NAME, ID_NAME };
        boolean[] shouldReverseType = {false, false};
        comparators.put(TYPE_NAME, new CaseNoteDTOComparatorInternal( propertiesType, shouldReverseType));

        final String[] propertiesTitle = { TITLE_NAME, ID_NAME };
        boolean[] shouldReverseTitle = {false, false};
        comparators.put(TITLE_NAME, new CaseNoteDTOComparatorInternal( propertiesTitle, shouldReverseTitle));

        final String[] propertiesRecordedVS = { PERSON_LASTNAME_NAME, PERSON_FIRSTNAME_NAME, ID_NAME };
        boolean[] shouldReverseRecordedVS= {false, false, false};
        comparators.put(RECORDED_VS, new CaseNoteDTOComparatorInternal( propertiesRecordedVS, shouldReverseRecordedVS));

        final String[] propertiesCreatedBy = { CREATED_BY_LASTNAME_NAME, CREATED_BY_FIRSTNAME_NAME, ID_NAME };
        boolean[] shouldReverseCreatedBy= {false, false, false};
        comparators.put(CREATED_BY_NAME, new CaseNoteDTOComparatorInternal( propertiesCreatedBy, shouldReverseCreatedBy));

        final String[] propertiesOrganisation = { ORGANISATION_NAME, ID_NAME };
        boolean[] shouldReverseOrganisation= {false, false};
        comparators.put(ORGANISATION_NAME, new CaseNoteDTOComparatorInternal( propertiesOrganisation, shouldReverseOrganisation));

        final String[] propertiesScore = { LUCENE_INDEX_SCORE};
        boolean[] shouldReverseScore = {false};
        comparators.put(LUCENE_INDEX_SCORE, new CaseNoteDTOComparatorInternal( propertiesScore, shouldReverseScore));

    }

    private CaseNoteDTOComparatorInternal comparator = null;

    public static final String ID_NAME = "id";
    public static final String EFFECTIVE_DATE_NAME = "effectiveDate";
    public static final String TYPE_NAME = "displayCaseNoteType";
    public static final String TITLE_NAME = "title";
    public static final String PERSON_LASTNAME_NAME = "personLastName";
    public static final String PERSON_FIRSTNAME_NAME = "personFirstName";
    public static final String RECORDED_VS = "recordedVS";
    public static final String CREATED_BY_NAME = "createdBy";
    public static final String CREATED_BY_FIRSTNAME_NAME = "createdByFirstName";
    public static final String CREATED_BY_LASTNAME_NAME =  "createdByLastName";
    public static final String CREATED_ON = "createdOn";
    public static final String ORGANISATION_NAME = "organisationName";
    public static final String DEFAULT_FIELD_NAME = EFFECTIVE_DATE_NAME;
    public static final String LUCENE_INDEX_SCORE = "score";

    public CaseNoteDTOComparator(String fieldKeyName, boolean descending) {
        this.comparator = (CaseNoteDTOComparatorInternal)comparators.get(fieldKeyName);
        if(comparator==null) {
            this.comparator = (CaseNoteDTOComparatorInternal)comparators.get(DEFAULT_FIELD_NAME);
        }
        comparator.setDescending(descending);
    }

    public int compare(Object obj1, Object obj2) {

        return comparator.compare(obj1, obj2);
    }
}

我花了几个小时查看代码并进行实验，但找不到问题所在。除了为班级实施测试之外，我还想修复它，但找不到问题。我将非常感谢任何提示。

谢谢！

Answer 1

我的猜测：这是一个数据问题。您以相等的值返回 ComparatorConstants.LESS_THAN（为什么？），这意味着相等的数据将被任意排序。

如果排序算法不能容忍这种情况，则返回小于等于值也有引入无限循环的风险。

您确定这些字段已正确填充，并且您使用正确的名称引用它们吗？