1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2025 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ///////////////////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.checks.imports;
21
22 import java.util.ArrayList;
23 import java.util.List;
24 import java.util.regex.Pattern;
25
26 import com.puppycrawl.tools.checkstyle.StatelessCheck;
27 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
28 import com.puppycrawl.tools.checkstyle.api.DetailAST;
29 import com.puppycrawl.tools.checkstyle.api.FullIdent;
30 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
31 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
32
33 /**
34 * <div>
35 * Checks for imports from a set of illegal packages.
36 * </div>
37 *
38 * <p>
39 * Notes:
40 * Note: By default, the check rejects all {@code sun.*} packages since programs
41 * that contain direct calls to the {@code sun.*} packages are
42 * <a href="https://www.oracle.com/java/technologies/faq-sun-packages.html">
43 * "not guaranteed to work on all Java-compatible platforms"</a>. To reject other
44 * packages, set property {@code illegalPkgs} to a list of the illegal packages.
45 * </p>
46 *
47 * @since 3.0
48 */
49 @StatelessCheck
50 public class IllegalImportCheck
51 extends AbstractCheck {
52
53 /**
54 * A key is pointing to the warning message text in "messages.properties"
55 * file.
56 */
57 public static final String MSG_KEY = "import.illegal";
58
59 /** The compiled regular expressions for packages. */
60 private final List<Pattern> illegalPkgsRegexps = new ArrayList<>();
61
62 /** The compiled regular expressions for classes. */
63 private final List<Pattern> illegalClassesRegexps = new ArrayList<>();
64
65 /**
66 * Specify packages to reject, if <b>regexp</b> property is not set, checks
67 * if import is the part of package. If <b>regexp</b> property is set, then
68 * list of packages will be interpreted as regular expressions.
69 * Note, all properties for match will be used.
70 */
71 private String[] illegalPkgs;
72
73 /**
74 * Specify class names to reject, if <b>regexp</b> property is not set,
75 * checks if import equals class name. If <b>regexp</b> property is set,
76 * then list of class names will be interpreted as regular expressions.
77 * Note, all properties for match will be used.
78 */
79 private String[] illegalClasses;
80
81 /**
82 * Control whether the {@code illegalPkgs} and {@code illegalClasses}
83 * should be interpreted as regular expressions.
84 */
85 private boolean regexp;
86
87 /**
88 * Creates a new {@code IllegalImportCheck} instance.
89 */
90 public IllegalImportCheck() {
91 setIllegalPkgs("sun");
92 }
93
94 /**
95 * Setter to specify packages to reject, if <b>regexp</b> property is not set,
96 * checks if import is the part of package. If <b>regexp</b> property is set,
97 * then list of packages will be interpreted as regular expressions.
98 * Note, all properties for match will be used.
99 *
100 * @param from illegal packages
101 * @noinspection WeakerAccess
102 * @noinspectionreason WeakerAccess - we avoid 'protected' when possible
103 * @since 3.0
104 */
105 public final void setIllegalPkgs(String... from) {
106 illegalPkgs = from.clone();
107 illegalPkgsRegexps.clear();
108 for (String illegalPkg : illegalPkgs) {
109 illegalPkgsRegexps.add(CommonUtil.createPattern("^" + illegalPkg + "\\..*"));
110 }
111 }
112
113 /**
114 * Setter to specify class names to reject, if <b>regexp</b> property is not
115 * set, checks if import equals class name. If <b>regexp</b> property is set,
116 * then list of class names will be interpreted as regular expressions.
117 * Note, all properties for match will be used.
118 *
119 * @param from illegal classes
120 * @since 7.8
121 */
122 public void setIllegalClasses(String... from) {
123 illegalClasses = from.clone();
124 for (String illegalClass : illegalClasses) {
125 illegalClassesRegexps.add(CommonUtil.createPattern(illegalClass));
126 }
127 }
128
129 /**
130 * Setter to control whether the {@code illegalPkgs} and {@code illegalClasses}
131 * should be interpreted as regular expressions.
132 *
133 * @param regexp a {@code Boolean} value
134 * @since 7.8
135 */
136 public void setRegexp(boolean regexp) {
137 this.regexp = regexp;
138 }
139
140 @Override
141 public int[] getDefaultTokens() {
142 return getRequiredTokens();
143 }
144
145 @Override
146 public int[] getAcceptableTokens() {
147 return getRequiredTokens();
148 }
149
150 @Override
151 public int[] getRequiredTokens() {
152 return new int[] {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
153 }
154
155 @Override
156 public void visitToken(DetailAST ast) {
157 final FullIdent imp;
158 if (ast.getType() == TokenTypes.IMPORT) {
159 imp = FullIdent.createFullIdentBelow(ast);
160 }
161 else {
162 imp = FullIdent.createFullIdent(
163 ast.getFirstChild().getNextSibling());
164 }
165 final String importText = imp.getText();
166 if (isIllegalImport(importText)) {
167 log(ast, MSG_KEY, importText);
168 }
169 }
170
171 /**
172 * Checks if an import matches one of the regular expressions
173 * for illegal packages or illegal class names.
174 *
175 * @param importText the argument of the import keyword
176 * @return if {@code importText} matches one of the regular expressions
177 * for illegal packages or illegal class names
178 */
179 private boolean isIllegalImportByRegularExpressions(String importText) {
180 boolean result = false;
181 for (Pattern pattern : illegalPkgsRegexps) {
182 if (pattern.matcher(importText).matches()) {
183 result = true;
184 break;
185 }
186 }
187 for (Pattern pattern : illegalClassesRegexps) {
188 if (pattern.matcher(importText).matches()) {
189 result = true;
190 break;
191 }
192 }
193 return result;
194 }
195
196 /**
197 * Checks if an import is from a package or class name that must not be used.
198 *
199 * @param importText the argument of the import keyword
200 * @return if {@code importText} contains an illegal package prefix or equals illegal class name
201 */
202 private boolean isIllegalImportByPackagesAndClassNames(String importText) {
203 boolean result = false;
204 for (String element : illegalPkgs) {
205 if (importText.startsWith(element + ".")) {
206 result = true;
207 break;
208 }
209 }
210 if (illegalClasses != null) {
211 for (String element : illegalClasses) {
212 if (importText.equals(element)) {
213 result = true;
214 break;
215 }
216 }
217 }
218 return result;
219 }
220
221 /**
222 * Checks if an import is from a package or class name that must not be used.
223 *
224 * @param importText the argument of the import keyword
225 * @return if {@code importText} is illegal import
226 */
227 private boolean isIllegalImport(String importText) {
228 final boolean result;
229 if (regexp) {
230 result = isIllegalImportByRegularExpressions(importText);
231 }
232 else {
233 result = isIllegalImportByPackagesAndClassNames(importText);
234 }
235 return result;
236 }
237
238 }