org.sonar.java.checks.ObjectFinalizeOverridenCallsSuperFinalizeCheck.java Source code

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Here is the source code for org.sonar.java.checks.ObjectFinalizeOverridenCallsSuperFinalizeCheck.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 com.google.common.collect.Iterables;
import org.sonar.check.Rule;
import org.sonar.java.RspecKey;
import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
import org.sonar.plugins.java.api.semantic.Symbol;
import org.sonar.plugins.java.api.semantic.Type;
import org.sonar.plugins.java.api.tree.BlockTree;
import org.sonar.plugins.java.api.tree.ExpressionStatementTree;
import org.sonar.plugins.java.api.tree.IdentifierTree;
import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
import org.sonar.plugins.java.api.tree.MethodInvocationTree;
import org.sonar.plugins.java.api.tree.MethodTree;
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 org.sonar.plugins.java.api.tree.TryStatementTree;

import javax.annotation.Nullable;
import java.util.List;

@Rule(key = "ObjectFinalizeOverridenCallsSuperFinalizeCheck")
@RspecKey("S1114")
public class ObjectFinalizeOverridenCallsSuperFinalizeCheck extends IssuableSubscriptionVisitor {

    private static final String FINALIZE = "finalize";

    private MethodInvocationTree lastStatementTree;

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

    @Override
    public void visitNode(Tree tree) {
        if (!hasSemantic()) {
            return;
        }
        if (tree.is(Kind.METHOD_INVOCATION)) {
            MethodInvocationTree methodInvocationTree = (MethodInvocationTree) tree;
            if (methodInvocationTree.methodSelect().is(Kind.MEMBER_SELECT)) {
                MemberSelectExpressionTree mset = (MemberSelectExpressionTree) methodInvocationTree.methodSelect();
                if (FINALIZE.equals(mset.identifier().name()) && mset.expression().is(Kind.IDENTIFIER)
                        && "super".equals(((IdentifierTree) mset.expression()).name())) {
                    lastStatementTree = methodInvocationTree;
                }
            }
        } else if (isFinalize(((MethodTree) tree).symbol())) {
            lastStatementTree = null;
        }
    }

    @Override
    public void leaveNode(Tree tree) {
        if (hasSemantic() && tree.is(Kind.METHOD)) {
            MethodTree methodTree = (MethodTree) tree;
            if (isFinalize(methodTree.symbol()) && doesOverrideFinalize(methodTree.symbol().owner())) {
                if (lastStatementTree == null) {
                    reportIssue(methodTree.simpleName(),
                            "Add a call to super.finalize() at the end of this Object.finalize() implementation.");
                } else if (!isLastStatement(methodTree, lastStatementTree)) {
                    reportIssue(lastStatementTree,
                            "Move this super.finalize() call to the end of this Object.finalize() implementation.");
                }
            }
        }
    }

    private static boolean isLastStatement(MethodTree methodTree, MethodInvocationTree lastStatementTree) {
        BlockTree blockTree = methodTree.block();
        if (blockTree != null && blockTree.body().stream().anyMatch(statement -> statement.is(Kind.TRY_STATEMENT)
                && isLastStatement(((TryStatementTree) statement).finallyBlock(), lastStatementTree))) {
            return true;
        }
        return isLastStatement(blockTree, lastStatementTree);
    }

    private static boolean isLastStatement(@Nullable BlockTree blockTree, MethodInvocationTree lastStatementTree) {
        if (blockTree != null) {
            StatementTree last = Iterables.getLast(blockTree.body());
            if (last.is(Kind.EXPRESSION_STATEMENT)) {
                return lastStatementTree.equals(((ExpressionStatementTree) last).expression());
            } else if (last.is(Kind.TRY_STATEMENT)) {
                return isLastStatement(((TryStatementTree) last).finallyBlock(), lastStatementTree);
            }
        }
        return false;
    }

    private static boolean isFinalize(Symbol symbol) {
        if (FINALIZE.equals(symbol.name()) && symbol.isMethodSymbol()) {
            Symbol.MethodSymbol methodSymbol = (Symbol.MethodSymbol) symbol;
            return "void".equals(methodSymbol.returnType().name()) && methodSymbol.parameterTypes().isEmpty();
        }
        return false;
    }

    private static boolean doesOverrideFinalize(Symbol classSymbol) {
        if (classSymbol.isTypeSymbol()) {
            Type superClassType = ((Symbol.TypeSymbol) classSymbol).superClass();
            while (superClassType != null && !superClassType.is("java.lang.Object")) {
                Symbol.TypeSymbol currentClass = superClassType.symbol();
                if (currentClass.lookupSymbols(FINALIZE).stream()
                        .anyMatch(ObjectFinalizeOverridenCallsSuperFinalizeCheck::isFinalize)) {
                    return true;
                }
                superClassType = currentClass.superClass();
            }
        }
        return false;
    }

}