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.util.lang;
17
18 /**
19 * Utility class to check an argument.
20 */
21 public final class Arg
22 {
23 // ********************************* Fields *********************************
24
25 // --- constants ------------------------------------------------------------
26
27 // --- members --------------------------------------------------------------
28
29 // ****************************** Initializer *******************************
30
31 // ****************************** Constructors ******************************
32
33 /**
34 * Utility class pattern.
35 */
36 private Arg()
37 {
38 }
39
40 // ****************************** Inner Classes *****************************
41
42 // ********************************* Methods ********************************
43
44 // --- init -----------------------------------------------------------------
45
46 // --- get&set --------------------------------------------------------------
47
48 // --- business -------------------------------------------------------------
49
50 /**
51 * Checks if {@code value} is <code>null</code>.
52 *
53 * @param name the name of the argument of error reporting. Not used if no
54 * exception is thrown. May be <code>null</code>, although not
55 * recommended.
56 * @param value the value of the argument to check to be not {@code null}.
57 * @return the passed in {@code value}.
58 * @throws NullPointerException if {@code value} is <code>null</code>.
59 * @param <T> the type of the argument to check.
60 */
61 public static <T> T checkNotNull(final String name, final T value)
62 throws NullPointerException
63 {
64 checkNotNull(name, value, null);
65 return value;
66 }
67
68 /**
69 * Checks if {@code value} is <code>null</code> providing an additional
70 * message.
71 *
72 * @param name the name of the argument of error reporting. Not used if no
73 * exception is thrown. May be <code>null</code>, although not
74 * recommended.
75 * @param value the value of the argument to check to be not {@code null}.
76 * @param message the message to pass to the exception as additional
77 * information to the standard message being generated.
78 * @return the passed in {@code value}.
79 * @throws NullPointerException if {@code value} is <code>null</code>.
80 * @param <T> the type of the argument to check.
81 */
82 public static <T> T checkNotNull(final String name, final T value,
83 final String message) throws NullPointerException
84 {
85 if (value == null)
86 {
87 throw new NullArgumentException(name, message);
88 }
89
90 return value;
91 }
92
93 /**
94 * Checks if {@code value} is blank.
95 *
96 * @param name the name of the argument of error reporting. Not used if no
97 * exception is thrown. May be <code>null</code>, although not
98 * recommended.
99 * @param value the value of the argument to check to be not blank.
100 * @return the passed in {@code value}.
101 * @throws NullArgumentException if {@code value} is <code>null</code>.
102 * @throws BlankArgumentException if {@code value} is blank.
103 * @param <T> a character sequence like a {@link String}.
104 */
105 public static <T extends CharSequence> T checkNotBlank(final String name,
106 final T value) throws NullArgumentException, BlankArgumentException
107 {
108 checkNotBlank(name, value, null);
109 return value;
110 }
111
112 /**
113 * Checks if {@code value} is blank providing an additional message.
114 *
115 * @param name the name of the argument of error reporting. Not used if no
116 * exception is thrown. May be <code>null</code>, although not
117 * recommended.
118 * @param value the value of the argument to check to be not blank.
119 * @param message the message to pass to the exception as additional
120 * information to the standard message being generated.
121 * @return the passed in {@code value}.
122 * @throws NullArgumentException if {@code value} is <code>null</code>.
123 * @throws BlankArgumentException if {@code value} is blank.
124 * @param <T> a character sequence like a {@link String}.
125 */
126 public static <T extends CharSequence> T checkNotBlank(final String name,
127 final T value, final String message) throws NullArgumentException,
128 BlankArgumentException
129 {
130 if (value == null)
131 {
132 throw new NullArgumentException(name, message);
133 }
134 if (isBlank(value))
135 {
136 throw new BlankArgumentException(name, message);
137 }
138
139 return value;
140 }
141
142 /**
143 * Checks if {@code value} is blank except <code>null</code>.
144 *
145 * @param name the name of the argument of error reporting. Not used if no
146 * exception is thrown. May be <code>null</code>, although not
147 * recommended.
148 * @param value the value of the argument to check to be not blank but may be
149 * <code>null</code>.
150 * @return the passed in {@code value}.
151 * @throws BlankExceptNullArgumentException if {@code value} is blank and not
152 * <code>null</code>.
153 * @param <T> a character sequence like a {@link String}.
154 */
155 public static <T extends CharSequence> T checkNotBlankExceptNull(
156 final String name, final T value) throws BlankExceptNullArgumentException
157 {
158 checkNotBlankExceptNull(name, value, null);
159 return value;
160 }
161
162 /**
163 * Checks if {@code value} is blank except <code>null</code> providing an
164 * additional message.
165 *
166 * @param name the name of the argument of error reporting. Not used if no
167 * exception is thrown. May be <code>null</code>, although not
168 * recommended.
169 * @param value the value of the argument to check to be not blank but may be
170 * <code>null</code>.
171 * @param message the message to pass to the exception as additional
172 * information to the standard message being generated.
173 * @return the passed in {@code value}.
174 * @throws BlankExceptNullArgumentException if {@code value} is blank and not
175 * <code>null</code>.
176 * @param <T> a character sequence like a {@link String}.
177 */
178 public static <T extends CharSequence> T checkNotBlankExceptNull(
179 final String name, final T value, final String message)
180 throws BlankExceptNullArgumentException
181 {
182 if (value != null && isBlank(value))
183 {
184 throw new BlankArgumentException(name, message);
185 }
186 return value;
187 }
188
189 // Copied from Apaches StringUtils and modified to cope with CharSequences.
190 // http://commons.apache.org/lang/api-2.6/org/apache/commons/lang/StringUtils.html#isBlank%28java.lang.String%29
191 private static <T extends CharSequence> boolean isBlank(final T str)
192 {
193 // CHECKSTYLE:OFF
194 int strLen;
195 if (str == null || (strLen = str.length()) == 0) // NOPMD
196 {
197 return true;
198 }
199 for (int i = 0; i < strLen; i++)
200 {
201 if ((Character.isWhitespace(str.charAt(i)) == false)) // NOPMD
202 {
203 return false;
204 }
205 }
206 return true;
207 // CHECKSTYLE:ON
208 }
209
210 // --- object basics --------------------------------------------------------
211
212 }