如何按字母数字顺序对guava多重映射(键和值)进行排序(不区分大小写)

时间:2014-06-11 02:36:40

标签: java guava multimap

我有一个Person类:

class Person {

    private String name;

    private String job;
    ... ...
}

我有个人名单:

personList.put(new Person("Pete","doctor"))
personList.put(new Person("pete","doctor"))
personList.put(new Person("Aaron","doctor"))
personList.put(new Person("Vivian","doctor"))
personList.put(new Person("Mary","teacher"))

我想显示作业的人员列表分组,名称和作业都是字母数字顺序(不区分大小写),作为以下数据格式。

doctor
>>Aaron
>>Pete
>>pete
>>Vivian
teacher
>>Mary

目前,我正在这样做:

public enum PersonComparator implements Comparator<Person> {
    NAME_JOB_INSENSTIVE_ASC {

        @Override
        public int compare(final Person obj1, final Person obj2) {

            String compareObj1 = obj1.getName();
            String compareObj2 = obj2.getName();

            int compareValue = compareObj1.compareTo(compareObj2);
        int compareValueIgnoreCase = compareObj1.compareToIgnoreCase(compareObj2);

            if(compareValueIgnoreCase == 0) {
                return compareValue >= 0 ? 1 : -1;
            } else {
                return compareValueIgnoreCase>= 0 ? ++compareValueIgnoreCase
                                                  : --compareValueIgnoreCase;
            }
        }
    }
}

ListMultimap<String, Person> personTableList = Multimaps.index(personList,
        new Function<Person, String>() {
        @Override
        public String apply(Person person) {
            return person.getJob();
        }
    });
TreeMultimap<String, Person> personTableTree = TreeMultimap.create(Ordering.natural(),
            PersonComparator.NAME_JOB_INSENSTIVE_ASC);
personTableTree.putAll(personTableList);

model.addAttribute(RequestParameter.Person_TABLE, personTableTree.asMap());

我认为PersonComparator不易阅读和理解。通过直接使用Guava API有什么好主意吗?感谢。

1 个答案:

答案 0 :(得分:2)

您可能想要使用ComparisonChain

从我收集的内容来看,您首先要比较不区分大小写,然后如果相等,则以区分大小写的方式执行比较。

public int compare(final Person p1, final Person p2)
{
  return ComparisonChain.start()
      .compare(p1.getName().toLowerCase(), p2.getName().toLowerCase())
      .compare(p1.getName(), p2.getName())
      .result();
}