@Nullable
public static PsiType getQualifierType(PsiMethodReferenceExpression expression) {
PsiType qualifierType = null;
final PsiTypeElement typeElement = expression.getQualifierType();
if (typeElement != null) {
qualifierType = typeElement.getType();
} else {
final PsiElement qualifier = expression.getQualifier();
if (qualifier instanceof PsiExpression) {
qualifierType = ((PsiExpression) qualifier).getType();
}
}
if (qualifierType == null) {
final QualifierResolveResult qualifierResolveResult = getQualifierResolveResult(expression);
final PsiClass containingClass = qualifierResolveResult.getContainingClass();
if (containingClass == null) {
return null;
}
qualifierType =
JavaPsiFacade.getElementFactory(expression.getProject()).createType(containingClass);
}
return qualifierType;
}
@NotNull
public static QualifierResolveResult getQualifierResolveResult(
@NotNull PsiMethodReferenceExpression methodReferenceExpression) {
PsiClass containingClass = null;
PsiSubstitutor substitutor = PsiSubstitutor.EMPTY;
final PsiExpression expression = methodReferenceExpression.getQualifierExpression();
if (expression != null) {
final PsiType expressionType = getExpandedType(expression.getType(), expression);
PsiClassType.ClassResolveResult result = PsiUtil.resolveGenericsClassInType(expressionType);
containingClass = result.getElement();
if (containingClass != null) {
substitutor = result.getSubstitutor();
}
if (containingClass == null && expression instanceof PsiReferenceExpression) {
final JavaResolveResult resolveResult =
((PsiReferenceExpression) expression).advancedResolve(false);
final PsiElement resolve = resolveResult.getElement();
if (resolve instanceof PsiClass) {
containingClass = (PsiClass) resolve;
substitutor = resolveResult.getSubstitutor();
return new QualifierResolveResult(containingClass, substitutor, true);
}
}
} else {
final PsiTypeElement typeElement = methodReferenceExpression.getQualifierType();
if (typeElement != null) {
PsiType type = getExpandedType(typeElement.getType(), typeElement);
PsiClassType.ClassResolveResult result = PsiUtil.resolveGenericsClassInType(type);
containingClass = result.getElement();
if (containingClass != null) {
return new QualifierResolveResult(containingClass, result.getSubstitutor(), true);
}
}
}
return new QualifierResolveResult(containingClass, substitutor, false);
}