001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.coding;
021
022import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026
027/**
028 * <div>
029 * Restricts nested {@code for} blocks to a specified depth.
030 * </div>
031 *
032 * @since 5.3
033 */
034@FileStatefulCheck
035public final class NestedForDepthCheck extends AbstractCheck {
036
037    /**
038     * A key is pointing to the warning message text in "messages.properties" file.
039     */
040    public static final String MSG_KEY = "nested.for.depth";
041
042    /** Specify maximum allowed nesting depth. */
043    private int max = 1;
044    /** Current nesting depth. */
045    private int depth;
046
047    /**
048     * Creates a new {@code NestedForDepthCheck} instance.
049     */
050    public NestedForDepthCheck() {
051        // no code by default
052    }
053
054    /**
055     * Setter to specify maximum allowed nesting depth.
056     *
057     * @param max maximum allowed nesting depth.
058     * @since 5.3
059     */
060    public void setMax(int max) {
061        this.max = max;
062    }
063
064    @Override
065    public int[] getDefaultTokens() {
066        return getRequiredTokens();
067    }
068
069    @Override
070    public int[] getAcceptableTokens() {
071        return getRequiredTokens();
072    }
073
074    @Override
075    public int[] getRequiredTokens() {
076        return new int[] {TokenTypes.LITERAL_FOR};
077    }
078
079    @Override
080    public void beginTree(DetailAST rootAST) {
081        depth = 0;
082    }
083
084    @Override
085    public void visitToken(DetailAST ast) {
086        if (depth > max) {
087            log(ast, MSG_KEY, depth, max);
088        }
089        ++depth;
090    }
091
092    @Override
093    public void leaveToken(DetailAST ast) {
094        --depth;
095    }
096
097}