1 /*
2 * Copyright (c) 2011-2024 Qulice.com
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met: 1) Redistributions of source code must retain the above
9 * copyright notice, this list of conditions and the following
10 * disclaimer. 2) Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following
12 * disclaimer in the documentation and/or other materials provided
13 * with the distribution. 3) Neither the name of the Qulice.com nor
14 * the names of its contributors may be used to endorse or promote
15 * products derived from this software without specific prior written
16 * permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
20 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
23 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
27 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
29 * OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31 package com.qulice.checkstyle;
32
33 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
34 import com.puppycrawl.tools.checkstyle.api.DetailAST;
35 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
36 import java.util.HashSet;
37 import java.util.Set;
38
39 /**
40 * Checks if inner classes are properly accessed using their qualified name
41 * with the outer class.
42 *
43 * @since 0.18
44 * @todo #738:30min Static inner classes should be qualified with outer class
45 * Implement QualifyInnerClassCheck so it follows what defined in
46 * QualifyInnerClassCheck test and add this check to checks.xml and CheckTest.
47 */
48 public final class QualifyInnerClassCheck extends AbstractCheck {
49 // FIXME: do we need to clear these fields in the end?
50 /**
51 * Set of all nested classes.
52 */
53 private final Set<String> nested = new HashSet<>();
54
55 /**
56 * Whether we already visited root class of the .java file.
57 */
58 private boolean root;
59
60 @Override
61 public int[] getDefaultTokens() {
62 return new int[]{
63 TokenTypes.CLASS_DEF,
64 TokenTypes.ENUM_DEF,
65 TokenTypes.INTERFACE_DEF,
66 TokenTypes.LITERAL_NEW,
67 };
68 }
69
70 @Override
71 public int[] getAcceptableTokens() {
72 return this.getDefaultTokens();
73 }
74
75 @Override
76 public int[] getRequiredTokens() {
77 return this.getDefaultTokens();
78 }
79
80 @Override
81 public void visitToken(final DetailAST ast) {
82 if (ast.getType() == TokenTypes.CLASS_DEF
83 || ast.getType() == TokenTypes.ENUM_DEF
84 || ast.getType() == TokenTypes.INTERFACE_DEF) {
85 this.scanForNestedClassesIfNecessary(ast);
86 }
87 if (ast.getType() == TokenTypes.LITERAL_NEW) {
88 this.visitNewExpression(ast);
89 }
90 }
91
92 /**
93 * Checks if class to be instantiated is nested and unqualified.
94 *
95 * FIXME: currently only simple paths are detected
96 * (i.e. `new Foo`, but not `new Foo.Bar`)
97 * @param expr EXPR LITERAL_NEW node that needs to be checked
98 */
99 private void visitNewExpression(final DetailAST expr) {
100 final DetailAST child = expr.getFirstChild();
101 if (child.getType() == TokenTypes.IDENT) {
102 if (this.nested.contains(child.getText())) {
103 this.log(child, "Static inner class should be qualified with outer class");
104 }
105 } else if (child.getType() != TokenTypes.DOT) {
106 final String message = String.format("unsupported input %d", child.getType());
107 throw new IllegalStateException(message);
108 }
109 }
110
111 /**
112 * If provided class is top-level, scans it for nested classes.
113 * FIXME: currently it assumes there can be only one top-level class
114 *
115 * @param node Class-like AST node
116 */
117 private void scanForNestedClassesIfNecessary(final DetailAST node) {
118 if (!this.root) {
119 this.root = true;
120 this.scanClass(node);
121 }
122 }
123
124 /**
125 * Scans class for all nested sub-classes.
126 *
127 * FIXME: checkstyle discourages manual traversing of AST,
128 * but exactly this is happening here.
129 * @param node Class-like AST node that needs to be checked
130 */
131 private void scanClass(final DetailAST node) {
132 this.nested.add(getClassName(node));
133 final DetailAST content = node.findFirstToken(TokenTypes.OBJBLOCK);
134 if (content == null) {
135 return;
136 }
137 for (
138 DetailAST child = content.getFirstChild();
139 child != null;
140 child = child.getNextSibling()
141 ) {
142 if (child.getType() == TokenTypes.CLASS_DEF
143 || child.getType() == TokenTypes.ENUM_DEF
144 || child.getType() == TokenTypes.INTERFACE_DEF) {
145 this.scanClass(child);
146 }
147 }
148 }
149
150 /**
151 * Returns class name.
152 * @param clazz Class-like AST node
153 * @return Class name
154 */
155 private static String getClassName(final DetailAST clazz) {
156 for (
157 DetailAST child = clazz.getFirstChild();
158 child != null;
159 child = child.getNextSibling()
160 ) {
161 if (child.getType() == TokenTypes.IDENT) {
162 return child.getText();
163 }
164 }
165 throw new IllegalStateException("unexpected input: can not find class name");
166 }
167 }