org.sonar.java.checks.StaticFieldUpateCheck.java Source code

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Here is the source code for org.sonar.java.checks.StaticFieldUpateCheck.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.sonar.check.Rule;
import org.sonar.java.matcher.MethodMatcher;
import org.sonar.java.model.ModifiersUtils;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.tree.ArrayAccessExpressionTree;
import org.sonar.plugins.java.api.tree.AssignmentExpressionTree;
import org.sonar.plugins.java.api.tree.ExpressionTree;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
import org.sonar.plugins.java.api.tree.MethodTree;
import org.sonar.plugins.java.api.tree.Modifier;
import org.sonar.plugins.java.api.tree.Tree;
import org.sonar.plugins.java.api.tree.Tree.Kind;
import org.sonar.plugins.java.api.tree.UnaryExpressionTree;

import java.util.Deque;
import java.util.LinkedList;
import java.util.List;

@Rule(key = "S2696")
public class StaticFieldUpateCheck extends AbstractInSynchronizeChecker {

    private static final Kind[] ASSIGNMENT_EXPRESSIONS = new Kind[] { Kind.AND_ASSIGNMENT, Kind.ASSIGNMENT,
            Kind.DIVIDE_ASSIGNMENT, Kind.LEFT_SHIFT_ASSIGNMENT, Kind.MINUS_ASSIGNMENT, Kind.MULTIPLY_ASSIGNMENT,
            Kind.OR_ASSIGNMENT, Kind.PLUS_ASSIGNMENT, Kind.REMAINDER_ASSIGNMENT,
            Kind.UNSIGNED_RIGHT_SHIFT_ASSIGNMENT, Kind.XOR_ASSIGNMENT };

    private static final Kind[] UNARY_EXPRESSIONS = new Kind[] { Kind.POSTFIX_DECREMENT, Kind.POSTFIX_INCREMENT,
            Kind.PREFIX_DECREMENT, Kind.PREFIX_INCREMENT };

    private Deque<Boolean> withinStaticMethod = new LinkedList<>();

    @Override
    public List<Kind> nodesToVisit() {
        ImmutableList.Builder<Kind> builder = ImmutableList.builder();
        builder.addAll(super.nodesToVisit());
        builder.add(Kind.STATIC_INITIALIZER);
        builder.add(ASSIGNMENT_EXPRESSIONS);
        builder.add(UNARY_EXPRESSIONS);
        return builder.build();
    }

    @Override
    public void visitNode(Tree tree) {
        // use AbstractInSynchronizeChecker logic to check synchronized blocks
        super.visitNode(tree);

        if (tree.is(Kind.METHOD)) {
            withinStaticMethod.push(isMethodStatic((MethodTree) tree));
        } else if (tree.is(Kind.STATIC_INITIALIZER)) {
            withinStaticMethod.push(true);
        } else if (hasSemantic() && isInInstanceMethod() && !hasAnyParentStatic() && !hasAnyParentSync()) {
            if (tree.is(ASSIGNMENT_EXPRESSIONS)) {
                checkVariableModification(((AssignmentExpressionTree) tree).variable());
            } else if (tree.is(UNARY_EXPRESSIONS)) {
                checkVariableModification(((UnaryExpressionTree) tree).expression());
            }
        }
    }

    private boolean hasAnyParentStatic() {
        return withinStaticMethod.contains(true);
    }

    private boolean isInInstanceMethod() {
        return !withinStaticMethod.isEmpty() && !withinStaticMethod.peek();
    }

    private static boolean isMethodStatic(MethodTree tree) {
        return ModifiersUtils.hasModifier(tree.modifiers(), Modifier.STATIC);
    }

    @Override
    public void leaveNode(Tree tree) {
        // use AbstractInSynchronizeChecker logic to keep updated synchronized blocks tracking
        super.leaveNode(tree);

        if (tree.is(Tree.Kind.METHOD, Kind.STATIC_INITIALIZER)) {
            withinStaticMethod.pop();
        }
    }

    private void checkVariableModification(ExpressionTree expression) {
        if (expression.is(Kind.IDENTIFIER)) {
            checkFieldModification((IdentifierTree) expression);
        } else if (expression.is(Kind.MEMBER_SELECT)) {
            checkFieldModification(((MemberSelectExpressionTree) expression).identifier());
        } else if (expression.is(Kind.ARRAY_ACCESS_EXPRESSION)) {
            checkVariableModification(((ArrayAccessExpressionTree) expression).expression());
        }
    }

    private void checkFieldModification(IdentifierTree identifier) {
        Symbol variable = identifier.symbol();
        if (isStaticField(variable)) {
            reportIssue(identifier, "Make the enclosing method \"static\" or remove this set.");
        }
    }

    private static boolean isStaticField(Symbol symbol) {
        return symbol.isVariableSymbol() && symbol.owner().isTypeSymbol() && symbol.isStatic();
    }

    @Override
    protected List<MethodMatcher> getMethodInvocationMatchers() {
        return ImmutableList.of();
    }
}