ClassInitializerMayBeStaticInspection.java

/*
 * Copyright 2000-2009 JetBrains s.r.o.
 *
 * 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.
 */

/*
 * @author max
 */
package com.siyeh.ig.performance;

import com.intellij.codeInspection.InspectionManager;
import com.intellij.openapi.extensions.Extensions;
import com.intellij.openapi.extensions.ExtensionsArea;
import com.intellij.openapi.util.Condition;
import com.intellij.psi.*;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import com.siyeh.ig.InspectionGadgetsFix;
import com.siyeh.ig.fixes.ChangeModifierFix;
import com.siyeh.ig.psiutils.ClassUtils;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;

public class ClassInitializerMayBeStaticInspection extends BaseInspection {
  @Override
  public boolean isEnabledByDefault() {
    return true;
  }

  @Override
  @NotNull
  protected String buildErrorString(Object... infos) {
    return InspectionGadgetsBundle.message(
      "class.initializer.may.be.static.problem.descriptor");
  }

  @Override
  protected InspectionGadgetsFix buildFix(Object... infos) {
    return new ChangeModifierFix(PsiModifier.STATIC);
  }

  @Override
  @Nls
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "class.initializer.may.be.static.display.name");
  }

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

  private static class ClassInitializerCanBeStaticVisitor extends BaseInspectionVisitor {
    @Override
    public void visitClassInitializer(PsiClassInitializer initializer) {
      if (initializer.hasModifierProperty(PsiModifier.STATIC)) return;

      final PsiClass containingClass =
        ClassUtils.getContainingClass(initializer);
      if (containingClass == null) {
        return;
      }
      final Condition<PsiElement>[] addins = InspectionManager.CANT_BE_STATIC_EXTENSION.getExtensions();
      for (Condition<PsiElement> addin : addins) {
        if (addin.value(initializer)) {
          return;
        }
      }
      final PsiElement scope = containingClass.getScope();
      if (!(scope instanceof PsiJavaFile) &&
          !containingClass.hasModifierProperty(PsiModifier.STATIC)) {
        return;
      }

      final MethodReferenceVisitor visitor =
        new MethodReferenceVisitor(initializer);
      initializer.accept(visitor);
      if (!visitor.areReferencesStaticallyAccessible()) {
        return;
      }

      registerClassInitializerError(initializer);
    }
  }
}