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.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
027import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
028import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
029
030/**
031 * <p>
032 * Checks for illegal tokens. By default labels are prohibited.
033 * </p>
034 * <p>
035 * Rationale: Certain language features can harm readability, lead to
036 * confusion or are not obvious to novice developers. Other features
037 * may be discouraged in certain frameworks, such as not having
038 * native methods in Enterprise JavaBeans components.
039 * </p>
040 * <ul>
041 * <li>
042 * Property {@code tokens} - tokens to check
043 * Type is {@code int[]}.
044 * Default value is:
045 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LABELED_STAT">
046 * LABELED_STAT</a>.
047 * </li>
048 * </ul>
049 * <p>
050 * To configure the check:
051 * </p>
052 * <pre>
053 * &lt;module name=&quot;IllegalToken&quot;/&gt;
054 * </pre>
055 * <p>Example:</p>
056 * <pre>
057 * public void myTest() {
058 *     outer: // violation
059 *     for (int i = 0; i &lt; 5; i++) {
060 *         if (i == 1) {
061 *             break outer;
062 *         }
063 *     }
064 * }
065 * </pre>
066 * <p>
067 * To configure the check to report violation on token LITERAL_NATIVE:
068 * </p>
069 * <pre>
070 * &lt;module name=&quot;IllegalToken&quot;&gt;
071 *   &lt;property name=&quot;tokens&quot; value=&quot;LITERAL_NATIVE&quot;/&gt;
072 * &lt;/module&gt;
073 * </pre>
074 * <p>Example:</p>
075 * <pre>
076 * public native void myTest(); // violation
077 * </pre>
078 * <p>
079 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
080 * </p>
081 * <p>
082 * Violation Message Keys:
083 * </p>
084 * <ul>
085 * <li>
086 * {@code illegal.token}
087 * </li>
088 * </ul>
089 *
090 * @since 3.2
091 */
092@StatelessCheck
093public class IllegalTokenCheck
094    extends AbstractCheck {
095
096    /**
097     * A key is pointing to the warning message text in "messages.properties"
098     * file.
099     */
100    public static final String MSG_KEY = "illegal.token";
101
102    @Override
103    public int[] getDefaultTokens() {
104        return new int[] {
105            TokenTypes.LABELED_STAT,
106        };
107    }
108
109    @Override
110    public int[] getAcceptableTokens() {
111        return TokenUtil.getAllTokenIds();
112    }
113
114    @Override
115    public int[] getRequiredTokens() {
116        return CommonUtil.EMPTY_INT_ARRAY;
117    }
118
119    @Override
120    public boolean isCommentNodesRequired() {
121        return true;
122    }
123
124    @Override
125    public void visitToken(DetailAST ast) {
126        log(
127            ast,
128            MSG_KEY,
129            convertToString(ast)
130        );
131    }
132
133    /**
134     * Converts given AST node to string representation.
135     *
136     * @param ast node to be represented as string
137     * @return string representation of AST node
138     */
139    private static String convertToString(DetailAST ast) {
140        final String tokenText;
141        switch (ast.getType()) {
142            case TokenTypes.LABELED_STAT:
143                tokenText = ast.getFirstChild().getText() + ast.getText();
144                break;
145            // multiline tokens need to become singlelined
146            case TokenTypes.COMMENT_CONTENT:
147                tokenText = JavadocUtil.escapeAllControlChars(ast.getText());
148                break;
149            default:
150                tokenText = ast.getText();
151                break;
152        }
153        return tokenText;
154    }
155
156}