plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/codeInspection/control/GroovyIfStatementWithIdenticalBranchesInspection.java

/*
 * Copyright 2000-2014 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.
 */
package org.jetbrains.plugins.groovy.codeInspection.control;

import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.openapi.project.Project;
import com.intellij.psi.PsiElement;
import com.intellij.util.IncorrectOperationException;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.plugins.groovy.codeInspection.BaseInspection;
import org.jetbrains.plugins.groovy.codeInspection.BaseInspectionVisitor;
import org.jetbrains.plugins.groovy.codeInspection.GroovyFix;
import org.jetbrains.plugins.groovy.codeInspection.utils.EquivalenceChecker;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.GrIfStatement;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.GrStatement;

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

  @Override
  @NotNull
  public String getDisplayName() {
    return "If statement with identical branches";
  }

  @Override
  @NotNull
  public String getGroupDisplayName() {
    return CONTROL_FLOW;
  }

  @Override
  public String buildErrorString(Object... args) {
    return "'#ref' statement with identical branches #loc";
  }

  @Override
  public GroovyFix buildFix(@NotNull PsiElement location) {
    return new CollapseIfFix();
  }

  private static class CollapseIfFix extends GroovyFix {

    @Override
    @NotNull
    public String getName() {
      return "Collapse 'if' statement'";
    }

    @Override
    public void doFix(Project project, ProblemDescriptor descriptor) throws IncorrectOperationException {
      final PsiElement identifier = descriptor.getPsiElement();
      final GrIfStatement statement = (GrIfStatement) identifier.getParent();
      assert statement != null;
      final GrStatement thenBranch = statement.getThenBranch();
      replaceStatement(statement, thenBranch);
    }
  }

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

  private static class IfStatementWithIdenticalBranchesVisitor extends BaseInspectionVisitor {

    @Override
    public void visitIfStatement(@NotNull GrIfStatement statement) {
      super.visitIfStatement(statement);
      final GrStatement thenBranch = statement.getThenBranch();
      final GrStatement elseBranch = statement.getElseBranch();
      if (thenBranch == null || elseBranch == null) {
        return;
      }
      if (EquivalenceChecker.statementsAreEquivalent(thenBranch, elseBranch)) {
        registerStatementError(statement);
      }
    }
  }
}