1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io;
18
19 import java.io.Serializable;
20
21 /**
22 * Enumeration of IO case sensitivity.
23 * <p>
24 * Different filing systems have different rules for case-sensitivity.
25 * Windows is case-insensitive, Unix is case-sensitive.
26 * <p>
27 * This class captures that difference, providing an enumeration to
28 * control how filename comparisons should be performed. It also provides
29 * methods that use the enumeration to perform comparisons.
30 * <p>
31 * Wherever possible, you should use the <code>check</code> methods in this
32 * class to compare filenames.
33 *
34 * @author Stephen Colebourne
35 * @version $Id: IOCase.java 484844 2006-12-08 23:27:18Z ggregory $
36 * @since Commons IO 1.3
37 */
38 public final class IOCase implements Serializable {
39
40 /**
41 * The constant for case sensitive regardless of operating system.
42 */
43 public static final IOCase SENSITIVE = new IOCase("Sensitive", true);
44 /**
45 * The constant for case insensitive regardless of operating system.
46 */
47 public static final IOCase INSENSITIVE = new IOCase("Insensitive", false);
48 /**
49 * The constant for case sensitivity determined by the current operating system.
50 * Windows is case-insensitive when comparing filenames, Unix is case-sensitive.
51 * <p>
52 * If you derialize this constant of Windows, and deserialize on Unix, or vice
53 * versa, then the value of the case-sensitivity flag will change.
54 */
55 public static final IOCase SYSTEM = new IOCase("System", !FilenameUtils.isSystemWindows());
56
57 /** Serialization version. */
58 private static final long serialVersionUID = -6343169151696340687L;
59
60 /** The enumeration name. */
61 private final String name;
62 /** The sensitivity flag. */
63 private final transient boolean sensitive;
64
65 //-----------------------------------------------------------------------
66 /**
67 * Factory method to create an IOCase from a name.
68 *
69 * @param name the name to find
70 * @return the IOCase object
71 * @throws IllegalArgumentException if the name is invalid
72 */
73 public static IOCase forName(String name) {
74 if (IOCase.SENSITIVE.name.equals(name)){
75 return IOCase.SENSITIVE;
76 }
77 if (IOCase.INSENSITIVE.name.equals(name)){
78 return IOCase.INSENSITIVE;
79 }
80 if (IOCase.SYSTEM.name.equals(name)){
81 return IOCase.SYSTEM;
82 }
83 throw new IllegalArgumentException("Invalid IOCase name: " + name);
84 }
85
86 //-----------------------------------------------------------------------
87 /**
88 * Private constructor.
89 *
90 * @param name the name
91 * @param sensitive the sensitivity
92 */
93 private IOCase(String name, boolean sensitive) {
94 this.name = name;
95 this.sensitive = sensitive;
96 }
97
98 /**
99 * Replaces the enumeration from the stream with a real one.
100 * This ensures that the correct flag is set for SYSTEM.
101 *
102 * @return the resolved object
103 */
104 private Object readResolve() {
105 return forName(name);
106 }
107
108 //-----------------------------------------------------------------------
109 /**
110 * Gets the name of the constant.
111 *
112 * @return the name of the constant
113 */
114 public String getName() {
115 return name;
116 }
117
118 /**
119 * Does the object represent case sensitive comparison.
120 *
121 * @return true if case sensitive
122 */
123 public boolean isCaseSensitive() {
124 return sensitive;
125 }
126
127 //-----------------------------------------------------------------------
128 /**
129 * Compares two strings using the case-sensitivity rule.
130 * <p>
131 * This method mimics {@link String#equals} but takes case-sensitivity
132 * into account.
133 *
134 * @param str1 the first string to compare, not null
135 * @param str2 the second string to compare, not null
136 * @return true if equal using the case rules
137 * @throws NullPointerException if either string is null
138 */
139 public boolean checkEquals(String str1, String str2) {
140 if (str1 == null || str2 == null) {
141 throw new NullPointerException("The strings must not be null");
142 }
143 return sensitive ? str1.equals(str2) : str1.equalsIgnoreCase(str2);
144 }
145
146 /**
147 * Checks if one string starts with another using the case-sensitivity rule.
148 * <p>
149 * This method mimics {@link String#startsWith(String)} but takes case-sensitivity
150 * into account.
151 *
152 * @param str the string to check, not null
153 * @param start the start to compare against, not null
154 * @return true if equal using the case rules
155 * @throws NullPointerException if either string is null
156 */
157 public boolean checkStartsWith(String str, String start) {
158 return str.regionMatches(!sensitive, 0, start, 0, start.length());
159 }
160
161 /**
162 * Checks if one string ends with another using the case-sensitivity rule.
163 * <p>
164 * This method mimics {@link String#endsWith} but takes case-sensitivity
165 * into account.
166 *
167 * @param str the string to check, not null
168 * @param end the end to compare against, not null
169 * @return true if equal using the case rules
170 * @throws NullPointerException if either string is null
171 */
172 public boolean checkEndsWith(String str, String end) {
173 int endLen = end.length();
174 return str.regionMatches(!sensitive, str.length() - endLen, end, 0, endLen);
175 }
176
177 /**
178 * Checks if one string contains another at a specific index using the case-sensitivity rule.
179 * <p>
180 * This method mimics parts of {@link String#regionMatches(boolean, int, String, int, int)}
181 * but takes case-sensitivity into account.
182 *
183 * @param str the string to check, not null
184 * @param strStartIndex the index to start at in str
185 * @param search the start to search for, not null
186 * @return true if equal using the case rules
187 * @throws NullPointerException if either string is null
188 */
189 public boolean checkRegionMatches(String str, int strStartIndex, String search) {
190 return str.regionMatches(!sensitive, strStartIndex, search, 0, search.length());
191 }
192
193 /**
194 * Converts the case of the input String to a standard format.
195 * Subsequent operations can then use standard String methods.
196 *
197 * @param str the string to convert, null returns null
198 * @return the lower-case version if case-insensitive
199 */
200 String convertCase(String str) {
201 if (str == null) {
202 return null;
203 }
204 return sensitive ? str : str.toLowerCase();
205 }
206
207 //-----------------------------------------------------------------------
208 /**
209 * Gets a string describing the sensitivity.
210 *
211 * @return a string describing the sensitivity
212 */
213 public String toString() {
214 return name;
215 }
216
217 }