UnnecessarySuperQualifierInspection.java

/*
 * Copyright 2008-2016 Bas Leijdekkers
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.siyeh.ig.style;

import com.intellij.codeInspection.CleanupLocalInspectionTool;
import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.codeInspection.ProblemHighlightType;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.util.IncorrectOperationException;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import com.siyeh.ig.InspectionGadgetsFix;
import com.siyeh.ig.psiutils.MethodUtils;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class UnnecessarySuperQualifierInspection extends BaseInspection implements CleanupLocalInspectionTool {

  @Override
  @Nls
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "unnecessary.super.qualifier.display.name");
  }

  @Override
  @NotNull
  protected String buildErrorString(Object... infos) {
    return InspectionGadgetsBundle.message(
      "unnecessary.super.qualifier.problem.descriptor"
    );
  }

  @Override
  @Nullable
  protected InspectionGadgetsFix buildFix(Object... infos) {
    return new UnnecessarySuperQualifierFix();
  }

  private static class UnnecessarySuperQualifierFix
    extends InspectionGadgetsFix {
    @Override
    @NotNull
    public String getFamilyName() {
      return InspectionGadgetsBundle.message(
        "unnecessary.super.qualifier.quickfix");
    }

    @Override
    protected void doFix(Project project, ProblemDescriptor descriptor)
      throws IncorrectOperationException {
      final PsiElement element = descriptor.getPsiElement();
      element.delete();
    }
  }

  @Override
  public BaseInspectionVisitor buildVisitor() {
    return new UnnecessarySuperQualifierVisitor();
  }

  private static class UnnecessarySuperQualifierVisitor
    extends BaseInspectionVisitor {

    @Override
    public void visitSuperExpression(PsiSuperExpression expression) {
      super.visitSuperExpression(expression);
      final PsiJavaCodeReferenceElement qualifier = expression.getQualifier();
      if (qualifier != null) {
        return;
      }
      final PsiElement parent = expression.getParent();
      if (!(parent instanceof PsiReferenceExpression)) {
        return;
      }
      final PsiReferenceExpression referenceExpression = (PsiReferenceExpression)parent;
      final PsiElement grandParent = referenceExpression.getParent();
      if (grandParent instanceof PsiMethodCallExpression) {
        final PsiMethodCallExpression methodCallExpression =
          (PsiMethodCallExpression)grandParent;
        if (!hasUnnecessarySuperQualifier(methodCallExpression)) {
          return;
        }
      }
      else {
        if (!hasUnnecessarySuperQualifier(referenceExpression)) {
          return;
        }
      }
      registerError(expression, ProblemHighlightType.LIKE_UNUSED_SYMBOL);
    }

    private static boolean hasUnnecessarySuperQualifier(PsiReferenceExpression referenceExpression) {
      final PsiClass parentClass = PsiTreeUtil.getParentOfType(referenceExpression, PsiClass.class);
      if (parentClass == null) {
        return false;
      }
      final PsiElement target = referenceExpression.resolve();
      if (!(target instanceof PsiField)) {
        return false;
      }
      final PsiField superField = (PsiField)target;
      final PsiReferenceExpression copy = (PsiReferenceExpression)referenceExpression.copy();
      final PsiElement qualifier = copy.getQualifier();
      if (qualifier == null) {
        return false;
      }
      qualifier.delete(); // remove super
      final JavaResolveResult resolveResult = copy.advancedResolve(false);
      return resolveResult.isValidResult() && superField == resolveResult.getElement();
    }

    private static boolean hasUnnecessarySuperQualifier(PsiMethodCallExpression methodCallExpression) {
      final PsiMethod superMethod = methodCallExpression.resolveMethod();
      if (superMethod == null || MethodUtils.isOverridden(superMethod)) {
        return false;
      }
      // check that super.m() and m() resolve to the same method
      final PsiMethodCallExpression copy = (PsiMethodCallExpression)methodCallExpression.copy();
      final PsiReferenceExpression methodExpression = copy.getMethodExpression();
      final PsiElement qualifier = methodExpression.getQualifier();
      if (qualifier == null) {
        return false;
      }
      qualifier.delete(); //remove super
      final JavaResolveResult resolveResult = copy.resolveMethodGenerics();
      return resolveResult.isValidResult() && superMethod == resolveResult.getElement();
    }
  }
}