org.sonar.java.checks.naming.MethodNamedEqualsCheck.java Source code

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Here is the source code for org.sonar.java.checks.naming.MethodNamedEqualsCheck.java

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/*
 * SonarQube Java
 * Copyright (C) 2012-2017 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.naming;

import com.google.common.collect.ImmutableList;
import org.apache.commons.lang.BooleanUtils;
import org.sonar.check.Rule;
import org.sonar.java.checks.helpers.ExpressionsHelper;
import org.sonar.java.model.declaration.MethodTreeImpl;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.MethodTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.VariableTree;

import java.util.List;

@Rule(key = "S1201")
public class MethodNamedEqualsCheck extends IssuableSubscriptionVisitor {

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

    @Override
    public void visitNode(Tree tree) {
        MethodTree methodTree = (MethodTree) tree;
        if ("equals".equalsIgnoreCase(methodTree.simpleName().name()) && !hasSingleObjectParameter(methodTree)
                && !isOverriding(methodTree)) {
            reportIssue(methodTree.simpleName(),
                    "Either override Object.equals(Object), or totally rename the method to prevent any confusion.");
        }
    }

    private static boolean hasSingleObjectParameter(MethodTree methodTree) {
        List<VariableTree> parameters = methodTree.parameters();
        if (parameters.size() != 1) {
            return false;
        }
        return isObjectType(parameters.get(0));
    }

    private static boolean isObjectType(VariableTree variableTree) {
        String type = ExpressionsHelper.concatenate((ExpressionTree) variableTree.type());
        return "Object".equals(type) || "java.lang.Object".equals(type);
    }

    private static boolean isOverriding(MethodTree methodTree) {
        return BooleanUtils.isTrue(((MethodTreeImpl) methodTree).isOverriding());
    }
}