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

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/*
 * SonarQube Java
 * Copyright (C) 2012-2024 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 Sonar Source-Available License Version 1, as published by SonarSource SA.
 *
 * 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 Sonar Source-Available License for more details.
 *
 * You should have received a copy of the Sonar Source-Available License
 * along with this program; if not, see https://sonarsource.com/license/ssal/
 */
package org.sonar.java.checks;

import java.util.Collections;
import java.util.List;
import javax.annotation.CheckForNull;
import org.sonar.check.Rule;
import org.sonarsource.analyzer.commons.collections.ListUtils;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.semantic.MethodMatchers;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.tree.BaseTreeVisitor;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.ForEachStatement;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
import org.sonar.plugins.java.api.tree.MethodInvocationTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.Tree.Kind;

@Rule(key = "S2864")
public class KeySetInsteadOfEntrySetCheck extends IssuableSubscriptionVisitor {

  private static final MethodMatchers MAP_GET_METHOD = MethodMatchers.create()
    .ofSubTypes("java.util.Map")
    .names("get")
    .addParametersMatcher("java.lang.Object")
    .build();

  private static final MethodMatchers MAP_KEYSET_METHOD = MethodMatchers.create()
    .ofSubTypes("java.util.Map")
    .names("keySet")
    .addWithoutParametersMatcher()
    .build();

  @Override
  public List nodesToVisit() {
    return Collections.singletonList(Tree.Kind.FOR_EACH_STATEMENT);
  }

  @Override
  public void visitNode(Tree tree) {
    ForEachStatement forEachTree = (ForEachStatement) tree;
    ExpressionTree expressionTree = forEachTree.expression();
    if (expressionTree.is(Tree.Kind.METHOD_INVOCATION)) {
      MethodInvocationTree methodTree = (MethodInvocationTree) expressionTree;
      Symbol ownerSymbol = getOwnerSymbol(methodTree);
      if (ownerSymbol != null && MAP_KEYSET_METHOD.matches(methodTree)) {
        new GetUsageVisitor().isCallingGetWithSymbol(forEachTree, forEachTree.variable().symbol(), ownerSymbol);
      }
    }
  }

  @CheckForNull
  private static Symbol getOwnerSymbol(MethodInvocationTree tree) {
    ExpressionTree expressionTree = tree.methodSelect();
    // direct invocation: symbol is implicitly this
    if (expressionTree.is(Tree.Kind.IDENTIFIER)) {
      return tree.methodSymbol().owner();
    }
    expressionTree = ((MemberSelectExpressionTree) expressionTree).expression();
    if (expressionTree.is(Tree.Kind.IDENTIFIER)) {
      return ((IdentifierTree) expressionTree).symbol();
    } else {
      return getFieldAccessedUsingSuperOrThis(expressionTree);
    }
  }

  @CheckForNull
  private static Symbol getFieldAccessedUsingSuperOrThis(ExpressionTree expressionTree) {
    if (expressionTree.is(Tree.Kind.MEMBER_SELECT)) {
      MemberSelectExpressionTree memberSelectTree = (MemberSelectExpressionTree) expressionTree;
      if (memberSelectTree.expression().is(Tree.Kind.IDENTIFIER)) {
        String identifierText = ((IdentifierTree) memberSelectTree.expression()).identifierToken().text();
        if ("super".equals(identifierText) || "this".equals(identifierText)) {
          return memberSelectTree.identifier().symbol();
        }
      }
    }
    return null;
  }

  private class GetUsageVisitor extends BaseTreeVisitor {
    private Symbol variable;
    private boolean result;
    private Symbol mapSymbol;

    public void isCallingGetWithSymbol(ForEachStatement forEachTree, Symbol variable, Symbol mapSymbol) {
      this.variable = variable;
      result = false;
      this.mapSymbol = mapSymbol;
      scan(forEachTree.statement());
      if (result) {
        reportIssue(forEachTree.forKeyword(), "Iterate over the \"entrySet\" instead of the \"keySet\".");
      }
    }

    @Override
    public void visitMethodInvocation(MethodInvocationTree tree) {
      if (MAP_GET_METHOD.matches(tree)) {
        Tree firstArgument = ListUtils.getOnlyElement(tree.arguments());
        if (mapSymbol.equals(getOwnerSymbol(tree)) && firstArgument.is(Tree.Kind.IDENTIFIER) && ((IdentifierTree) firstArgument).symbol().equals(variable)) {
          result = true;
          return;
        }
      }
      super.visitMethodInvocation(tree);
    }
  }

}