1 /*
2 * Copyright 2011-2013 smartics, Kronseder & Reiner GmbH
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package de.smartics.checkstyle.checks.strings;
17
18 import java.nio.ByteBuffer;
19 import java.nio.CharBuffer;
20 import java.nio.charset.CharacterCodingException;
21 import java.nio.charset.Charset;
22 import java.nio.charset.CharsetDecoder;
23
24 import com.puppycrawl.tools.checkstyle.api.Check;
25 import com.puppycrawl.tools.checkstyle.api.DetailAST;
26 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
27
28 /**
29 * Check to detect usage of characters of disallowed encoding in String
30 * and character literals.
31 */
32 public class StringLiteralEncodingCheck extends Check
33 {
34 // ********************************* Fields *********************************
35
36 // --- constants ------------------------------------------------------------
37
38 // --- members --------------------------------------------------------------
39
40 /**
41 * The allowed encoding within String and character literals.
42 */
43 private String encoding;
44
45 /**
46 * The decoder dependent on the {@link #encoding}.
47 */
48 private CharsetDecoder decoder;
49
50 // ****************************** Initializer *******************************
51
52 // ****************************** Constructors ******************************
53
54 /**
55 * Default constructor.
56 */
57 public StringLiteralEncodingCheck()
58 {
59 this.encoding = "US-ASCII";
60 this.decoder = createDecoder(encoding);
61 }
62
63 // ****************************** Inner Classes *****************************
64
65 // ********************************* Methods ********************************
66
67 // --- init -----------------------------------------------------------------
68
69 private static CharsetDecoder createDecoder(final String encoding)
70 {
71 return Charset.forName(encoding).newDecoder();
72 }
73
74 // --- get&set --------------------------------------------------------------
75
76 /**
77 * Sets the allowed encoding within String literals.
78 *
79 * @param encoding the allowed encoding within String literals.
80 */
81 public void setEncoding(final String encoding)
82 {
83 this.encoding = encoding;
84 this.decoder = createDecoder(encoding);
85 }
86
87 // --- business -------------------------------------------------------------
88
89 /**
90 * {@inheritDoc}
91 *
92 * @see com.puppycrawl.tools.checkstyle.api.Check#getDefaultTokens()
93 */
94 @Override
95 public int[] getDefaultTokens()
96 {
97 return new int[]
98 { TokenTypes.STRING_LITERAL, TokenTypes.CHAR_LITERAL };
99 }
100
101 /**
102 * {@inheritDoc}
103 *
104 * @see com.puppycrawl.tools.checkstyle.api.Check#visitToken(com.puppycrawl.tools.checkstyle.api.DetailAST)
105 */
106 @Override
107 public void visitToken(final DetailAST ast)
108 {
109 final String literal = ast.getText();
110 if (!isProperlyEncoded(literal))
111 {
112 log(ast.getLineNo(), "not_supported_encoding", literal, encoding);
113 }
114 }
115
116 /**
117 * Inspired by <a href=
118 * "http://stackoverflow.com/questions/3585053/in-java-is-it-possible-to-check-if-a-string-is-only-ascii"
119 * >In Java, is it possible to check if a String is only ASCII?</a>.
120 */
121 private boolean isProperlyEncoded(final String string)
122 {
123 final byte[] stringBytes = string.getBytes();
124
125 try
126 {
127 final CharBuffer buffer = decoder.decode(ByteBuffer.wrap(stringBytes));
128 buffer.toString();
129 }
130 catch (final CharacterCodingException e)
131 {
132 return false;
133 }
134
135 return true;
136 }
137
138 // --- object basics --------------------------------------------------------
139
140 /**
141 * Returns the string representation of the class for debugging.
142 *
143 * @return the string representation of the class for debugging.
144 */
145 @Override
146 public String toString()
147 {
148 return "StringLiteralEncodingCheck with encoding '" + encoding + "'.";
149
150 }
151 }