001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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 * <p>
029 * Restricts nested {@code for} blocks to a specified depth.
030 * </p>
031 * <ul>
032 * <li>
033 * Property {@code max} - Specify maximum allowed nesting depth.
034 * Type is {@code int}.
035 * Default value is {@code 1}.
036 * </li>
037 * </ul>
038 * <p>
039 * To configure the check:
040 * </p>
041 * <pre>
042 * &lt;module name=&quot;NestedForDepth&quot;/&gt;
043 * </pre>
044 * <p>
045 * To configure the check to allow nesting depth 3:
046 * </p>
047 * <pre>
048 * &lt;module name=&quot;NestedForDepth&quot;&gt;
049 *   &lt;property name=&quot;max&quot; value=&quot;3&quot;/&gt;
050 * &lt;/module&gt;
051 * </pre>
052 * <p>
053 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
054 * </p>
055 * <p>
056 * Violation Message Keys:
057 * </p>
058 * <ul>
059 * <li>
060 * {@code nested.for.depth}
061 * </li>
062 * </ul>
063 *
064 * @since 5.3
065 */
066@FileStatefulCheck
067public final class NestedForDepthCheck extends AbstractCheck {
068
069    /**
070     * A key is pointing to the warning message text in "messages.properties"
071     * file.
072     */
073    public static final String MSG_KEY = "nested.for.depth";
074
075    /** Specify maximum allowed nesting depth. */
076    private int max = 1;
077    /** Current nesting depth. */
078    private int depth;
079
080    /**
081     * Setter to specify maximum allowed nesting depth.
082     *
083     * @param max maximum allowed nesting depth.
084     */
085    public void setMax(int max) {
086        this.max = max;
087    }
088
089    @Override
090    public int[] getDefaultTokens() {
091        return getRequiredTokens();
092    }
093
094    @Override
095    public int[] getAcceptableTokens() {
096        return getRequiredTokens();
097    }
098
099    @Override
100    public int[] getRequiredTokens() {
101        return new int[] {TokenTypes.LITERAL_FOR};
102    }
103
104    @Override
105    public void beginTree(DetailAST rootAST) {
106        depth = 0;
107    }
108
109    @Override
110    public void visitToken(DetailAST ast) {
111        if (depth > max) {
112            log(ast, MSG_KEY, depth, max);
113        }
114        ++depth;
115    }
116
117    @Override
118    public void leaveToken(DetailAST ast) {
119        --depth;
120    }
121
122}