How to query workitems in open state ?

I want to query workitems in open state by using client java API, but the following code doesn't work, anyone can help me?

IQueryableAttribute queryableAttribute1 = factory.findAttribute(projectArea, IWorkItem.STATE_PROPERTY, auditableClient, null);

Identifier sIdentifier1 = Identifier.create (com.ibm.team.workitem.common.model.IState.class, String.valueOf(IWorkflowInfo.OPEN_STATES)); 

AttributeExpression projectAreaExpression1 = new AttributeExpression(queryableAttribute1, AttributeOperation.EQUALS, sIdentifier1);



Term term = new Term(Operator.AND);

term.add(projectAreaExpression1);

IQueryResult<IResolvedResult<IWorkItem>> result = queryClient.getResolvedExpressionResults(projectArea, term, IWorkItem.SMALL_PROFILE);



IAttribute idAttribute = workItemClient.findAttribute(projectArea, IWorkItem.ID_PROPERTY, null);

while (result.hasNext(null)) {

			    IResolvedResult<IWorkItem> resolved = result.next(null);

			    wi = resolved.getItem();

			    System.out.println(wi.getValue(idAttribute));

			 }

I also tried this:

AttributeExpression projectAreaExpression1 = new AttributeExpression(queryableAttribute1, AttributeOperation.EQUALS, new StatusVariable(IWorkflowInfo.OPEN_STATES));

They all doesn't work. Am I using query API incorrect?