1 /*
2 * Copyright 2014 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5 * "License"); you may not use this file except in compliance with the License. You may obtain a
6 * 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 distributed under the License
11 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12 * or implied. See the License for the specific language governing permissions and limitations under
13 * the License.
14 */
15 package io.netty.util.internal;
16
17 import java.util.Collection;
18
19 /**
20 * A grab-bag of useful utility methods.
21 */
22 public final class ObjectUtil {
23
24 private ObjectUtil() {
25 }
26
27 /**
28 * Checks that the given argument is not null. If it is, throws {@link NullPointerException}.
29 * Otherwise, returns the argument.
30 */
31 public static <T> T checkNotNull(T arg, String text) {
32 if (arg == null) {
33 throw new NullPointerException(text);
34 }
35 return arg;
36 }
37
38 /**
39 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
40 * Otherwise, returns the argument.
41 */
42 public static int checkPositive(int i, String name) {
43 if (i <= 0) {
44 throw new IllegalArgumentException(name + ": " + i + " (expected: > 0)");
45 }
46 return i;
47 }
48
49 /**
50 * Checks that the given argument is strictly positive. If it is not, throws {@link IllegalArgumentException}.
51 * Otherwise, returns the argument.
52 */
53 public static long checkPositive(long i, String name) {
54 if (i <= 0) {
55 throw new IllegalArgumentException(name + ": " + i + " (expected: > 0)");
56 }
57 return i;
58 }
59
60 /**
61 * Checks that the given argument is positive or zero. If it is not , throws {@link IllegalArgumentException}.
62 * Otherwise, returns the argument.
63 */
64 public static int checkPositiveOrZero(int i, String name) {
65 if (i < 0) {
66 throw new IllegalArgumentException(name + ": " + i + " (expected: >= 0)");
67 }
68 return i;
69 }
70
71 /**
72 * Checks that the given argument is positive or zero. If it is not, throws {@link IllegalArgumentException}.
73 * Otherwise, returns the argument.
74 */
75 public static long checkPositiveOrZero(long i, String name) {
76 if (i < 0) {
77 throw new IllegalArgumentException(name + ": " + i + " (expected: >= 0)");
78 }
79 return i;
80 }
81
82 /**
83 * Checks that the given argument is neither null nor empty.
84 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
85 * Otherwise, returns the argument.
86 */
87 public static <T> T[] checkNonEmpty(T[] array, String name) {
88 checkNotNull(array, name);
89 checkPositive(array.length, name + ".length");
90 return array;
91 }
92
93 /**
94 * Checks that the given argument is neither null nor empty.
95 * If it is, throws {@link NullPointerException} or {@link IllegalArgumentException}.
96 * Otherwise, returns the argument.
97 */
98 public static <T extends Collection<?>> T checkNonEmpty(T collection, String name) {
99 checkNotNull(collection, name);
100 checkPositive(collection.size(), name + ".size");
101 return collection;
102 }
103
104 /**
105 * Resolves a possibly null Integer to a primitive int, using a default value.
106 * @param wrapper the wrapper
107 * @param defaultValue the default value
108 * @return the primitive value
109 */
110 public static int intValue(Integer wrapper, int defaultValue) {
111 return wrapper != null ? wrapper : defaultValue;
112 }
113
114 /**
115 * Resolves a possibly null Long to a primitive long, using a default value.
116 * @param wrapper the wrapper
117 * @param defaultValue the default value
118 * @return the primitive value
119 */
120 public static long longValue(Long wrapper, long defaultValue) {
121 return wrapper != null ? wrapper : defaultValue;
122 }
123 }