org.sonar.java.checks.ConstantMethodCheck.java Source code

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Here is the source code for org.sonar.java.checks.ConstantMethodCheck.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;

import com.google.common.collect.ImmutableList;

import org.apache.commons.lang.BooleanUtils;
import org.sonar.check.Rule;
import org.sonar.java.model.ModifiersUtils;
import org.sonar.java.model.declaration.MethodTreeImpl;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.tree.BlockTree;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.Modifier;
import org.sonar.plugins.java.api.tree.ReturnStatementTree;
import org.sonar.plugins.java.api.tree.StatementTree;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.Tree.Kind;

import javax.annotation.Nullable;

import java.util.List;

@Rule(key = "S3400")
public class ConstantMethodCheck extends IssuableSubscriptionVisitor {

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

    @Override
    public void visitNode(Tree tree) {
        MethodTreeImpl methodTree = (MethodTreeImpl) tree;
        BlockTree body = methodTree.block();
        if (!methodTree.modifiers().annotations().isEmpty()
                || ModifiersUtils.hasModifier(methodTree.modifiers(), Modifier.DEFAULT)) {
            return;
        }
        if (BooleanUtils.isFalse(methodTree.isOverriding()) && body != null && body.body().size() == 1) {
            StatementTree uniqueStatement = body.body().get(0);
            if (uniqueStatement.is(Kind.RETURN_STATEMENT)) {
                ExpressionTree returnedExpression = ((ReturnStatementTree) uniqueStatement).expression();
                if (isConstant(returnedExpression)) {
                    reportIssue(returnedExpression, "Remove this method and declare a constant for this value.");
                }
            }
        }
    }

    private static boolean isConstant(@Nullable ExpressionTree returnedExpression) {
        return returnedExpression != null && returnedExpression.is(Kind.INT_LITERAL, Kind.LONG_LITERAL,
                Kind.CHAR_LITERAL, Kind.STRING_LITERAL, Kind.DOUBLE_LITERAL, Kind.FLOAT_LITERAL);
    }
}