CallToStringConcatCanBeReplacedByOperatorInspection.java

/*
 * Copyright 2007-2010 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.ProblemDescriptor;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
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.PsiReplacementUtil;
import com.siyeh.ig.psiutils.MethodCallUtils;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class CallToStringConcatCanBeReplacedByOperatorInspection
  extends BaseInspection {

  @Override
  @Nls
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "call.to.string.concat.can.be.replaced.by.operator.display.name");
  }

  @Override
  @NotNull
  protected String buildErrorString(Object... infos) {
    return InspectionGadgetsBundle.message(
      "call.to.string.concat.can.be.replaced.by.operator.problem.descriptor");
  }

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

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

  private static class CallToStringConcatCanBeReplacedByOperatorFix
    extends InspectionGadgetsFix {

    @Override
    @NotNull
    public String getFamilyName() {
      return InspectionGadgetsBundle.message("call.to.string.concat.can.be.replaced.by.operator.quickfix");
    }

    @Override
    protected void doFix(Project project, ProblemDescriptor descriptor)
      throws IncorrectOperationException {
      final PsiElement element = descriptor.getPsiElement();
      final PsiElement parent = element.getParent();
      if (!(parent instanceof PsiReferenceExpression)) {
        return;
      }
      final PsiReferenceExpression referenceExpression =
        (PsiReferenceExpression)parent;
      final PsiExpression qualifier =
        referenceExpression.getQualifierExpression();
      if (qualifier == null) {
        return;
      }
      final PsiElement grandParent = referenceExpression.getParent();
      if (!(grandParent instanceof PsiMethodCallExpression)) {
        return;
      }
      final PsiMethodCallExpression methodCallExpression =
        (PsiMethodCallExpression)grandParent;
      final PsiExpressionList argumentList =
        methodCallExpression.getArgumentList();
      final PsiExpression[] arguments = argumentList.getExpressions();
      if (arguments.length != 1) {
        return;
      }
      final PsiExpression argument = arguments[0];
      @NonNls
      final String newExpression =
        qualifier.getText() + '+' + argument.getText();
      PsiReplacementUtil.replaceExpression(methodCallExpression, newExpression);
    }
  }

  private static class CallToStringConcatCanBeReplacedByOperatorVisitor
    extends BaseInspectionVisitor {

    @Override
    public void visitMethodCallExpression(
      PsiMethodCallExpression expression) {
      super.visitMethodCallExpression(expression);
      final Project project = expression.getProject();
      final JavaPsiFacade psiFacade = JavaPsiFacade.getInstance(project);
      final PsiClass stringClass =
        psiFacade.findClass(CommonClassNames.JAVA_LANG_STRING,
                            expression.getResolveScope());
      if (stringClass == null) {
        return;
      }
      final PsiClassType stringType =
        psiFacade.getElementFactory().createType(stringClass);
      if (!MethodCallUtils.isCallToMethod(expression,
                                          CommonClassNames.JAVA_LANG_STRING,
                                          stringType, "concat", stringType)) {
        return;
      }
      final PsiExpressionList argumentList = expression.getArgumentList();
      final PsiExpression[] arguments = argumentList.getExpressions();
      if (arguments.length != 1) {
        return;
      }
      final PsiElement parent = expression.getParent();
      if (parent instanceof PsiExpressionStatement) {
        return;
      }
      registerMethodCallError(expression);
    }
  }
}