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

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/*
 * SonarQube Java
 * Copyright (C) 2012-2025 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 org.sonar.check.Rule;
import org.sonar.plugins.java.api.JavaVersionAwareVisitor;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.JavaVersion;
import org.sonar.plugins.java.api.tree.LambdaExpressionTree;
import org.sonar.plugins.java.api.tree.SyntaxToken;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.VariableTree;

import java.util.Collections;
import java.util.List;


@Rule(key = "S1611")
public class LambdaOptionalParenthesisCheck extends IssuableSubscriptionVisitor implements JavaVersionAwareVisitor {

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

  @Override
  public boolean isCompatibleWithJavaVersion(JavaVersion version) {
    return version.isJava8Compatible();
  }

  @Override
  public void visitNode(Tree tree) {
    LambdaExpressionTree let = (LambdaExpressionTree) tree;
    SyntaxToken openParenToken = let.openParenToken();
    if (openParenToken != null && let.parameters().size() == 1) {
      VariableTree param = let.parameters().get(0);
      String identifier = param.simpleName().name();
      if (param.type().is(Tree.Kind.INFERED_TYPE)) {
        reportIssue(openParenToken, "Remove the parentheses around the \"" + identifier + "\" parameter" + context.getJavaVersion().java8CompatibilityMessage());
      }
    }
  }
}