无法将枚举列表传递到Hibernate查询中？

Question

I am trying to pass in a list of enums into my hibernate query. Here is what I am trying to do:

public Integer getReportRunsCount(Set<ReportRunStatus> statusSet, Optional<String> userId) {
    Query query = sessionFactory.getCurrentSession().createQuery("select count(1) from ReportRun r where r.status in (:fieldStatuses) and r.createdBy = :userId");
    query.setParameterList("fieldStatuses", Arrays.asList(statusSet));
    query.setString("userId", userId.orElse(null));
    return Ints.checkedCast((Long)query.uniqueResult());
}

ReportRunStatus.java:

public enum ReportRunStatus {
    STARTED,
    QUERYDATA,
    PROCESSINGDATA,
    COMPLETED,
    CANCELLED,
    ERROR;
}

I am just trying to pass in these fieldStatuses as a parameter where ReportRunStatus is a class of enums. However, I keep getting this error saying that

java.lang.ClassCastException: java.util.HashSet cannot be cast to java.lang.Enum

Any ideas why this might happen? I Looked at this link here: using enum list as parameter in HQL query as reference to do what I am trying to do but I keep getting the error above. Any help would be appreciated. Thanks!

Answer 1

What is causing problem is this one: Arrays.asList(statusSet)

This is simply creating a one-element list, with a Set as the value (ie a List<Set<ReportRunStatus>> . However setParameterList is expecting a Collection<ReportRunStatus> , hence it caused class cast exception because internally it was getting an element out (which is a HashSet<ReportRunStatus> ) and trying to cast it to a ReportRunStatus .

What you should do is something like

query.setParameterList("fieldStatuses", statusSet);

Answer 2

Try this,

 List<String> reportRunStatusList = new ArrayList<String>();
 for(ReportRunStatus reportRunStatus : statusSet){
     reportRunStatusList.add(reportRunStatus.toString);
 }
 query.setParameterList("fieldStatuses", reportRunStatusList);

You just needed to convert the enums to String explicitly.