UnnecessarilyQualifiedInnerClassAccessInspection.java

/*
 * Copyright 2010-2014 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.codeInspection.ui.SingleCheckboxOptionsPanel;
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.ImportUtils;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;

import javax.swing.*;

public class UnnecessarilyQualifiedInnerClassAccessInspection extends BaseInspection implements CleanupLocalInspectionTool {

  @SuppressWarnings({"PublicField"})
  public boolean ignoreReferencesNeedingImport = false;

  @Nls
  @NotNull
  @Override
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "unnecessarily.qualified.inner.class.access.display.name");
  }

  @NotNull
  @Override
  protected String buildErrorString(Object... infos) {
    final PsiClass aClass = (PsiClass)infos[0];
    return InspectionGadgetsBundle.message(
      "unnecessarily.qualified.inner.class.access.problem.descriptor",
      aClass.getName());
  }

  @Override
  public JComponent createOptionsPanel() {
    return new SingleCheckboxOptionsPanel(
      InspectionGadgetsBundle.message(
        "unnecessarily.qualified.inner.class.access.option"),
      this, "ignoreReferencesNeedingImport");
  }

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

  private static class UnnecessarilyQualifiedInnerClassAccessFix
    extends InspectionGadgetsFix {

    @Override
    @NotNull
    public String getFamilyName() {
      return InspectionGadgetsBundle.message(
        "unnecessarily.qualified.inner.class.access.quickfix");
    }

    @Override
    protected void doFix(Project project, ProblemDescriptor descriptor)
      throws IncorrectOperationException {
      final PsiElement element = descriptor.getPsiElement();
      final PsiElement parent = element.getParent();
      if (!(parent instanceof PsiJavaCodeReferenceElement)) {
        return;
      }
      final PsiJavaCodeReferenceElement referenceElement =
        (PsiJavaCodeReferenceElement)parent;
      final PsiElement target = referenceElement.resolve();
      if (!(target instanceof PsiClass)) {
        return;
      }
      final PsiClass aClass = (PsiClass)target;
      ImportUtils.addImportIfNeeded(aClass, element);
      final String shortName = aClass.getName();
      if (isReferenceToTarget(shortName, aClass, parent)) {
        element.delete();
      }
    }
  }

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

  private static boolean isReferenceToTarget(String referenceText, @NotNull PsiClass target, PsiElement context) {
    final PsiJavaCodeReferenceElement reference =
      JavaPsiFacade.getElementFactory(target.getProject()).createReferenceFromText(referenceText, context);
    final JavaResolveResult[] results = reference.multiResolve(false);
    if (results.length == 0) {
      return true;
    }
    if (results.length > 1) {
      return false;
    }
    final JavaResolveResult result = results[0];
    return result.isAccessible() && target.equals(result.getElement());
  }

  private class UnnecessarilyQualifiedInnerClassAccessVisitor
    extends BaseInspectionVisitor {

    @Override
    public void visitReferenceElement(
      PsiJavaCodeReferenceElement reference) {
      super.visitReferenceElement(reference);
      final PsiElement qualifier = reference.getQualifier();
      if (!(qualifier instanceof PsiJavaCodeReferenceElement)) {
        return;
      }
      if (isInImportOrPackage(reference)) {
        return;
      }
      final PsiJavaCodeReferenceElement referenceElement =
        (PsiJavaCodeReferenceElement)qualifier;
      final PsiReferenceParameterList parameterList =
        referenceElement.getParameterList();
      if (parameterList != null &&
          parameterList.getTypeParameterElements().length > 0) {
        return;
      }
      final PsiElement qualifierTarget = referenceElement.resolve();
      if (!(qualifierTarget instanceof PsiClass)) {
        return;
      }
      final PsiClass referenceClass =
        PsiTreeUtil.getParentOfType(reference, PsiClass.class);
      if (referenceClass == null) {
        return;
      }
      final PsiElement brace = referenceClass.getLBrace();
      if (!referenceClass.equals(qualifierTarget) || brace != null && brace.getTextOffset() > reference.getTextOffset()) {
        if (ignoreReferencesNeedingImport &&
            (PsiTreeUtil.isAncestor(referenceClass, qualifierTarget,
                                    true) ||
             !PsiTreeUtil.isAncestor(qualifierTarget,
                                     referenceClass, true))) {
          return;
        }
      }
      final PsiElement target = reference.resolve();
      if (!(target instanceof PsiClass)) {
        return;
      }
      final PsiClass aClass = (PsiClass)target;
      final PsiClass containingClass = aClass.getContainingClass();
      if (containingClass == null) {
        return;
      }
      if (!containingClass.equals(qualifierTarget)) {
        return;
      }
      final String shortName = aClass.getName();
      if (!isReferenceToTarget(shortName, aClass, reference)) {
        return;
      }
      registerError(qualifier, ProblemHighlightType.LIKE_UNUSED_SYMBOL, aClass);
    }

    @Override
    public void visitReferenceExpression(
      PsiReferenceExpression expression) {
      visitReferenceElement(expression);
    }

    private boolean isInImportOrPackage(PsiElement element) {
      while (element instanceof PsiJavaCodeReferenceElement) {
        element = element.getParent();
        if (element instanceof PsiImportStatementBase ||
            element instanceof PsiPackageStatement ||
            element instanceof PsiImportStaticReferenceElement) {
          return true;
        }
      }
      return false;
    }
  }
}