plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/bugs/InstanceofIncompatibleInterfaceInspection.java

/*
 * Copyright 2003-2013 Dave Griffith, 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.bugs;

import com.intellij.psi.*;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import com.siyeh.ig.psiutils.InheritanceUtil;
import org.jetbrains.annotations.NotNull;

public class InstanceofIncompatibleInterfaceInspection extends BaseInspection {

  @Override
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message("instanceof.with.incompatible.interface.display.name");
  }

  @Override
  @NotNull
  public String buildErrorString(Object... infos) {
    return InspectionGadgetsBundle.message("instanceof.with.incompatible.interface.problem.descriptor");
  }

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

  private static class InstanceofIncompatibleInterfaceVisitor extends BaseInspectionVisitor {

    @Override
    public void visitInstanceOfExpression(@NotNull PsiInstanceOfExpression expression) {
      super.visitInstanceOfExpression(expression);
      final PsiTypeElement castTypeElement = expression.getCheckType();
      if (castTypeElement == null) {
        return;
      }
      final PsiType castType = castTypeElement.getType();
      if (!(castType instanceof PsiClassType)) {
        return;
      }
      final PsiClassType castClassType = (PsiClassType)castType;
      final PsiExpression operand = expression.getOperand();
      final PsiType operandType = operand.getType();
      if (!(operandType instanceof PsiClassType)) {
        return;
      }
      final PsiClassType operandClassType = (PsiClassType)operandType;
      final PsiClass castClass = castClassType.resolve();
      if (castClass == null || !castClass.isInterface()) {
        return;
      }
      final PsiClass operandClass = operandClassType.resolve();
      if (operandClass == null || operandClass.isInterface()) {
        return;
      }
      if (InheritanceUtil.existsMutualSubclass(operandClass, castClass, isOnTheFly())) {
        return;
      }
      registerError(castTypeElement);
    }
  }
}