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.sizes;
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 * Checks for the number of types declared at the <i>outer</i> (or <i>root</i>) level in a file.
030 * </p>
031 * <p>
032 * Rationale: It is considered good practice to only define one outer type per file.
033 * </p>
034 * <ul>
035 * <li>
036 * Property {@code max} - Specify the maximum number of outer types allowed.
037 * Default value is {@code 1}.
038 * </li>
039 * </ul>
040 * <p>
041 * To configure the check to accept 1 outer type per file:
042 * </p>
043 * <pre>
044 * &lt;module name="OuterTypeNumber"/&gt;
045 * </pre>
046 * <p>
047 * To configure the check to accept 2 outer types per file:
048 * </p>
049 * <pre>
050 * &lt;module name="OuterTypeNumber"&gt;
051 *   &lt;property name="max" value="2"/&gt;
052 * &lt;/module&gt;
053 * </pre>
054 *
055 * @since 5.0
056 */
057@FileStatefulCheck
058public class OuterTypeNumberCheck extends AbstractCheck {
059
060    /**
061     * A key is pointing to the warning message text in "messages.properties"
062     * file.
063     */
064    public static final String MSG_KEY = "maxOuterTypes";
065
066    /** Specify the maximum number of outer types allowed. */
067    private int max = 1;
068    /** Tracks the current depth in types. */
069    private int currentDepth;
070    /** Tracks the number of outer types found. */
071    private int outerNum;
072
073    @Override
074    public int[] getDefaultTokens() {
075        return getRequiredTokens();
076    }
077
078    @Override
079    public int[] getAcceptableTokens() {
080        return getRequiredTokens();
081    }
082
083    @Override
084    public int[] getRequiredTokens() {
085        return new int[] {TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF,
086            TokenTypes.ENUM_DEF, TokenTypes.ANNOTATION_DEF, };
087    }
088
089    @Override
090    public void beginTree(DetailAST ast) {
091        currentDepth = 0;
092        outerNum = 0;
093    }
094
095    @Override
096    public void finishTree(DetailAST ast) {
097        if (max < outerNum) {
098            log(ast, MSG_KEY, outerNum, max);
099        }
100    }
101
102    @Override
103    public void visitToken(DetailAST ast) {
104        if (currentDepth == 0) {
105            outerNum++;
106        }
107        currentDepth++;
108    }
109
110    @Override
111    public void leaveToken(DetailAST ast) {
112        currentDepth--;
113    }
114
115    /**
116     * Setter to specify the maximum number of outer types allowed.
117     *
118     * @param max the new number.
119     */
120    public void setMax(int max) {
121        this.max = max;
122    }
123
124}