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

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/*
 * SonarQube Java
 * Copyright (C) 2012 SonarSource
 * [email protected]
 *
 * 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  02
 */
package org.sonar.java.checks;

import com.google.common.collect.ImmutableList;
import org.sonar.api.server.rule.RulesDefinition;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.java.JavaVersionAwareVisitor;
import org.sonar.java.checks.helpers.JavaVersionHelper;
import org.sonar.java.tag.Tag;
import org.sonar.plugins.java.api.tree.LambdaExpressionTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.VariableTree;
import org.sonar.squidbridge.annotations.ActivatedByDefault;
import org.sonar.squidbridge.annotations.SqaleConstantRemediation;
import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;

import javax.annotation.Nullable;

import java.util.List;


@Rule(
  key = "S1611",
  name = "Parentheses should be removed from a single lambda input parameter when its type is inferred",
  priority = Priority.MINOR,
  tags = {Tag.JAVA_8})
@ActivatedByDefault
@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.READABILITY)
@SqaleConstantRemediation("2min")
public class LambdaOptionalParenthesisCheck extends SubscriptionBaseVisitor implements JavaVersionAwareVisitor {

  @Override
  public List nodesToVisit() {
    return ImmutableList.of(Tree.Kind.LAMBDA_EXPRESSION);
  }

  @Override
  public boolean isCompatibleWithJavaVersion(@Nullable Integer version) {
    return JavaVersionHelper.java8Compatible(version);
  }

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