public void updateThrowsList(PsiClassType exceptionType) {
    if (!getSuperMethods().isEmpty()) {
      for (RefMethod refSuper : getSuperMethods()) {
        ((RefMethodImpl) refSuper).updateThrowsList(exceptionType);
      }
    } else if (myUnThrownExceptions != null) {
      if (exceptionType == null) {
        myUnThrownExceptions = null;
        return;
      }
      PsiClass exceptionClass = exceptionType.resolve();
      JavaPsiFacade facade = JavaPsiFacade.getInstance(myManager.getProject());
      for (int i = myUnThrownExceptions.size() - 1; i >= 0; i--) {
        String exceptionFqn = myUnThrownExceptions.get(i);
        PsiClass classType =
            facade.findClass(
                exceptionFqn, GlobalSearchScope.allScope(getRefManager().getProject()));
        if (InheritanceUtil.isInheritorOrSelf(exceptionClass, classType, true)
            || InheritanceUtil.isInheritorOrSelf(classType, exceptionClass, true)) {
          myUnThrownExceptions.remove(i);
        }
      }

      if (myUnThrownExceptions.isEmpty()) myUnThrownExceptions = null;
    }
  }
  protected boolean preprocessUsages(Ref<UsageInfo[]> refUsages) {
    final MultiMap<PsiElement, String> conflicts = new MultiMap<PsiElement, String>();

    checkExistingMethods(conflicts, true);
    checkExistingMethods(conflicts, false);
    final Collection<PsiClass> classes = ClassInheritorsSearch.search(myClass).findAll();
    for (FieldDescriptor fieldDescriptor : myFieldDescriptors) {
      final Set<PsiMethod> setters = new HashSet<PsiMethod>();
      final Set<PsiMethod> getters = new HashSet<PsiMethod>();

      for (PsiClass aClass : classes) {
        final PsiMethod getterOverrider =
            myDescriptor.isToEncapsulateGet()
                ? aClass.findMethodBySignature(fieldDescriptor.getGetterPrototype(), false)
                : null;
        if (getterOverrider != null) {
          getters.add(getterOverrider);
        }
        final PsiMethod setterOverrider =
            myDescriptor.isToEncapsulateSet()
                ? aClass.findMethodBySignature(fieldDescriptor.getSetterPrototype(), false)
                : null;
        if (setterOverrider != null) {
          setters.add(setterOverrider);
        }
      }
      if (!getters.isEmpty() || !setters.isEmpty()) {
        final PsiField field = fieldDescriptor.getField();
        for (PsiReference reference : ReferencesSearch.search(field)) {
          final PsiElement place = reference.getElement();
          if (place instanceof PsiReferenceExpression) {
            final PsiExpression qualifierExpression =
                ((PsiReferenceExpression) place).getQualifierExpression();
            final PsiClass ancestor;
            if (qualifierExpression == null) {
              ancestor = PsiTreeUtil.getParentOfType(place, PsiClass.class, false);
            } else {
              ancestor = PsiUtil.resolveClassInType(qualifierExpression.getType());
            }

            final boolean isGetter = !PsiUtil.isAccessedForWriting((PsiExpression) place);
            for (PsiMethod overridden : isGetter ? getters : setters) {
              if (InheritanceUtil.isInheritorOrSelf(myClass, ancestor, true)) {
                conflicts.putValue(
                    overridden,
                    "There is already a "
                        + RefactoringUIUtil.getDescription(overridden, true)
                        + " which would hide generated "
                        + (isGetter ? "getter" : "setter")
                        + " for "
                        + place.getText());
                break;
              }
            }
          }
        }
      }
    }
    return showConflicts(conflicts, refUsages.get());
  }
  private static boolean isSuperMethod(
      PsiClass aClass,
      HierarchicalMethodSignature hierarchicalMethodSignature,
      HierarchicalMethodSignature superSignatureHierarchical) {
    PsiMethod superMethod = superSignatureHierarchical.getMethod();
    PsiClass superClass = superMethod.getContainingClass();
    PsiClass containingClass = hierarchicalMethodSignature.getMethod().getContainingClass();
    if (!superMethod.isConstructor()) {
      if (!aClass.equals(superClass)) {
        if (PsiUtil.isAccessible(aClass.getProject(), superMethod, aClass, aClass)) {
          if (MethodSignatureUtil.isSubsignature(
              superSignatureHierarchical, hierarchicalMethodSignature)) {
            if (superClass != null) {
              if (superClass.isInterface()
                  || CommonClassNames.JAVA_LANG_OBJECT.equals(superClass.getQualifiedName())) {
                if (superMethod.hasModifierProperty(PsiModifier.DEFAULT)
                    || hierarchicalMethodSignature
                        .getMethod()
                        .hasModifierProperty(PsiModifier.DEFAULT)) {
                  return !InheritanceUtil.isInheritorOrSelf(superClass, containingClass, true);
                }
                return true;
              }

              if (containingClass != null) {
                if (containingClass.isInterface()) {
                  return false;
                }

                if (!aClass.isInterface()
                    && !InheritanceUtil.isInheritorOrSelf(superClass, containingClass, true)) {
                  return true;
                }
              }
            }
          }
        }
      }
    }
    return false;
  }
  private void checkExistingMethods(MultiMap<PsiElement, String> conflicts, boolean isGetter) {
    if (isGetter) {
      if (!myDescriptor.isToEncapsulateGet()) return;
    } else {
      if (!myDescriptor.isToEncapsulateSet()) return;
    }

    for (FieldDescriptor descriptor : myFieldDescriptors) {
      PsiMethod prototype =
          isGetter ? descriptor.getGetterPrototype() : descriptor.getSetterPrototype();

      final PsiType prototypeReturnType = prototype.getReturnType();
      PsiMethod existing = myClass.findMethodBySignature(prototype, true);
      if (existing != null) {
        final PsiType returnType = existing.getReturnType();
        if (!RefactoringUtil.equivalentTypes(
            prototypeReturnType, returnType, myClass.getManager())) {
          final String descr =
              PsiFormatUtil.formatMethod(
                  existing,
                  PsiSubstitutor.EMPTY,
                  PsiFormatUtilBase.SHOW_NAME
                      | PsiFormatUtilBase.SHOW_PARAMETERS
                      | PsiFormatUtilBase.SHOW_TYPE,
                  PsiFormatUtilBase.SHOW_TYPE);
          String message =
              isGetter
                  ? RefactoringBundle.message(
                      "encapsulate.fields.getter.exists",
                      CommonRefactoringUtil.htmlEmphasize(descr),
                      CommonRefactoringUtil.htmlEmphasize(prototype.getName()))
                  : RefactoringBundle.message(
                      "encapsulate.fields.setter.exists",
                      CommonRefactoringUtil.htmlEmphasize(descr),
                      CommonRefactoringUtil.htmlEmphasize(prototype.getName()));
          conflicts.putValue(existing, message);
        }
      } else {
        PsiClass containingClass = myClass.getContainingClass();
        while (containingClass != null && existing == null) {
          existing = containingClass.findMethodBySignature(prototype, true);
          if (existing != null) {
            for (PsiReference reference : ReferencesSearch.search(existing)) {
              final PsiElement place = reference.getElement();
              LOG.assertTrue(place instanceof PsiReferenceExpression);
              final PsiExpression qualifierExpression =
                  ((PsiReferenceExpression) place).getQualifierExpression();
              final PsiClass inheritor;
              if (qualifierExpression == null) {
                inheritor = PsiTreeUtil.getParentOfType(place, PsiClass.class, false);
              } else {
                inheritor = PsiUtil.resolveClassInType(qualifierExpression.getType());
              }

              if (InheritanceUtil.isInheritorOrSelf(inheritor, myClass, true)) {
                conflicts.putValue(
                    existing,
                    "There is already a "
                        + RefactoringUIUtil.getDescription(existing, true)
                        + " which would be hidden by generated "
                        + (isGetter ? "getter" : "setter"));
                break;
              }
            }
          }
          containingClass = containingClass.getContainingClass();
        }
      }
    }
  }