org.sonar.java.checks.AllBranchesAreIdenticalCheck Maven / Gradle / Ivy

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/*
 * SonarQube Java
 * Copyright (C) 2012-2018 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.java.checks;

import com.google.common.collect.Multimap;

import org.sonar.check.Rule;
import org.sonar.java.model.ExpressionUtils;
import org.sonar.java.model.SyntacticEquivalence;
import org.sonar.plugins.java.api.tree.CaseGroupTree;
import org.sonar.plugins.java.api.tree.ConditionalExpressionTree;
import org.sonar.plugins.java.api.tree.IfStatementTree;
import org.sonar.plugins.java.api.tree.SwitchStatementTree;
import org.sonar.plugins.java.api.tree.Tree;

import java.util.Arrays;
import java.util.List;

@Rule(key = "S3923")
public class AllBranchesAreIdenticalCheck extends IdenticalCasesInSwitchCheck {

  private static final String IF_SWITCH_MSG = "Remove this conditional structure or edit its code blocks so that they're not all the same.";

  @Override
  public List nodesToVisit() {
    return Arrays.asList(Tree.Kind.SWITCH_STATEMENT, Tree.Kind.IF_STATEMENT, Tree.Kind.CONDITIONAL_EXPRESSION);
  }

  @Override
  public void visitNode(Tree tree) {
    if (tree.is(Tree.Kind.SWITCH_STATEMENT)) {
      SwitchStatementTree switchStatement = (SwitchStatementTree) tree;
      Multimap identicalBranches = checkSwitchStatement(switchStatement);
      if (hasDefaultClause(switchStatement) && allBranchesSame(identicalBranches, switchStatement.cases().size())) {
        reportIssue(switchStatement.switchKeyword(), IF_SWITCH_MSG);
      }
    } else if (tree.is(Tree.Kind.IF_STATEMENT)) {
      IfStatementTree ifStatementTree = (IfStatementTree) tree;
      if (hasElseClause(ifStatementTree) && !tree.parent().is(Tree.Kind.IF_STATEMENT)) {
        IfElseChain ifElseChain = checkIfStatement(ifStatementTree);
        if (allBranchesSame(ifElseChain.branches, ifElseChain.totalBranchCount)) {
          reportIssue(ifStatementTree.ifKeyword(), IF_SWITCH_MSG);
        }
      }
    } else {
      checkConditionalExpression((ConditionalExpressionTree) tree);
    }
  }

  private void checkConditionalExpression(ConditionalExpressionTree node) {
    if (SyntacticEquivalence.areEquivalent(ExpressionUtils.skipParentheses(node.trueExpression()), ExpressionUtils.skipParentheses(node.falseExpression()))) {
      reportIssue(node.condition(), node.questionToken(), "This conditional operation returns the same value whether the condition is \"true\" or \"false\".");
    }
  }
}