9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import jdk.internal.misc.CDS;
29 import jdk.internal.vm.annotation.IntrinsicCandidate;
30 import jdk.internal.vm.annotation.Stable;
31
32 import java.lang.constant.Constable;
33 import java.lang.constant.DynamicConstantDesc;
34 import java.util.Optional;
35
36 import static java.lang.constant.ConstantDescs.BSM_EXPLICIT_CAST;
37 import static java.lang.constant.ConstantDescs.CD_byte;
38 import static java.lang.constant.ConstantDescs.CD_int;
39 import static java.lang.constant.ConstantDescs.DEFAULT_NAME;
40
41 /**
42 * The {@code Byte} class is the {@linkplain
43 * java.lang##wrapperClass wrapper class} for values of the primitive
44 * type {@code byte}. An object of type {@code Byte} contains a
45 * single field whose type is {@code byte}.
46 *
47 * <p>In addition, this class provides several methods for converting
48 * a {@code byte} to a {@code String} and a {@code String} to a {@code
49 * byte}, as well as other constants and methods useful when dealing
50 * with a {@code byte}.
51 *
52 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
53 * class; programmers should treat instances that are
54 * {@linkplain #equals(Object) equal} as interchangeable and should not
55 * use instances for synchronization, or unpredictable behavior may
56 * occur. For example, in a future release, synchronization may fail.
57 *
58 * @see java.lang.Number
59 * @since 1.1
60 */
61 @jdk.internal.ValueBased
62 public final class Byte extends Number implements Comparable<Byte>, Constable {
63
64 /**
65 * A constant holding the minimum value a {@code byte} can
66 * have, -2<sup>7</sup>.
67 */
68 public static final byte MIN_VALUE = -128;
69
70 /**
71 * A constant holding the maximum value a {@code byte} can
72 * have, 2<sup>7</sup>-1.
73 */
74 public static final byte MAX_VALUE = 127;
75
76 /**
77 * The {@code Class} instance representing the primitive type
78 * {@code byte}.
79 */
80 public static final Class<Byte> TYPE = Class.getPrimitiveClass("byte");
114 final int size = -(-128) + 127 + 1;
115
116 // Load and use the archived cache if it exists
117 CDS.initializeFromArchive(ByteCache.class);
118 if (archivedCache == null) {
119 Byte[] c = new Byte[size];
120 byte value = (byte)-128;
121 for(int i = 0; i < size; i++) {
122 c[i] = new Byte(value++);
123 }
124 archivedCache = c;
125 }
126 cache = archivedCache;
127 assert cache.length == size;
128 }
129 }
130
131 /**
132 * Returns a {@code Byte} instance representing the specified
133 * {@code byte} value.
134 * If a new {@code Byte} instance is not required, this method
135 * should generally be used in preference to the constructor
136 * {@link #Byte(byte)}, as this method is likely to yield
137 * significantly better space and time performance since
138 * all byte values are cached.
139 *
140 * @param b a byte value.
141 * @return a {@code Byte} instance representing {@code b}.
142 * @since 1.5
143 */
144 @IntrinsicCandidate
145 public static Byte valueOf(byte b) {
146 final int offset = 128;
147 return ByteCache.cache[(int)b + offset];
148 }
149
150 /**
151 * Parses the string argument as a signed {@code byte} in the
152 * radix specified by the second argument. The characters in the
153 * string must all be digits, of the specified radix (as
154 * determined by whether {@link java.lang.Character#digit(char,
155 * int)} returns a nonnegative value) except that the first
156 * character may be an ASCII minus sign {@code '-'}
157 * ({@code '\u005Cu002D'}) to indicate a negative value or an
158 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
159 * indicate a positive value. The resulting {@code byte} value is
160 * returned.
161 *
162 * <p>An exception of type {@code NumberFormatException} is
163 * thrown if any of the following situations occurs:
164 * <ul>
165 * <li> The first argument is {@code null} or is a string of
166 * length zero.
167 *
|
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import jdk.internal.misc.CDS;
29 import jdk.internal.misc.PreviewFeatures;
30 import jdk.internal.value.DeserializeConstructor;
31 import jdk.internal.vm.annotation.IntrinsicCandidate;
32 import jdk.internal.vm.annotation.Stable;
33
34 import java.lang.constant.Constable;
35 import java.lang.constant.DynamicConstantDesc;
36 import java.util.Optional;
37
38 import static java.lang.constant.ConstantDescs.BSM_EXPLICIT_CAST;
39 import static java.lang.constant.ConstantDescs.CD_byte;
40 import static java.lang.constant.ConstantDescs.DEFAULT_NAME;
41
42 /**
43 * The {@code Byte} class is the {@linkplain
44 * java.lang##wrapperClass wrapper class} for values of the primitive
45 * type {@code byte}. An object of type {@code Byte} contains a
46 * single field whose type is {@code byte}.
47 *
48 * <p>In addition, this class provides several methods for converting
49 * a {@code byte} to a {@code String} and a {@code String} to a {@code
50 * byte}, as well as other constants and methods useful when dealing
51 * with a {@code byte}.
52 *
53 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
54 * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
55 * as interchangeable and should not use instances for synchronization, mutexes, or
56 * with {@linkplain java.lang.ref.Reference object references}.
57 *
58 * <div class="preview-block">
59 * <div class="preview-comment">
60 * When preview features are enabled, {@code Byte} is a {@linkplain Class#isValue value class}.
61 * Use of value class instances for synchronization, mutexes, or with
62 * {@linkplain java.lang.ref.Reference object references} result in
63 * {@link IdentityException}.
64 * </div>
65 * </div>
66 *
67 * @see java.lang.Number
68 * @since 1.1
69 */
70 @jdk.internal.MigratedValueClass
71 @jdk.internal.ValueBased
72 public final class Byte extends Number implements Comparable<Byte>, Constable {
73
74 /**
75 * A constant holding the minimum value a {@code byte} can
76 * have, -2<sup>7</sup>.
77 */
78 public static final byte MIN_VALUE = -128;
79
80 /**
81 * A constant holding the maximum value a {@code byte} can
82 * have, 2<sup>7</sup>-1.
83 */
84 public static final byte MAX_VALUE = 127;
85
86 /**
87 * The {@code Class} instance representing the primitive type
88 * {@code byte}.
89 */
90 public static final Class<Byte> TYPE = Class.getPrimitiveClass("byte");
124 final int size = -(-128) + 127 + 1;
125
126 // Load and use the archived cache if it exists
127 CDS.initializeFromArchive(ByteCache.class);
128 if (archivedCache == null) {
129 Byte[] c = new Byte[size];
130 byte value = (byte)-128;
131 for(int i = 0; i < size; i++) {
132 c[i] = new Byte(value++);
133 }
134 archivedCache = c;
135 }
136 cache = archivedCache;
137 assert cache.length == size;
138 }
139 }
140
141 /**
142 * Returns a {@code Byte} instance representing the specified
143 * {@code byte} value.
144 * <div class="preview-block">
145 * <div class="preview-comment">
146 * <p>
147 * - When preview features are NOT enabled, {@code Byte} is an identity class.
148 * If a new {@code Byte} instance is not required, this method
149 * should generally be used in preference to the constructor
150 * {@link #Byte(byte)}, as this method is likely to yield
151 * significantly better space and time performance since
152 * all byte values are cached.
153 * </p>
154 * <p>
155 * - When preview features are enabled, {@code Byte} is a {@linkplain Class#isValue value class}.
156 * The {@code valueOf} behavior is the same as invoking the constructor,
157 * whether cached or not.
158 * </p>
159 * </div>
160 * </div>
161 *
162 * @param b a byte value.
163 * @return a {@code Byte} instance representing {@code b}.
164 * @since 1.5
165 */
166 @IntrinsicCandidate
167 @DeserializeConstructor
168 public static Byte valueOf(byte b) {
169 final int offset = 128;
170 return (!PreviewFeatures.isEnabled()) ? ByteCache.cache[(int)b + offset] : new Byte(b);
171 }
172
173 /**
174 * Parses the string argument as a signed {@code byte} in the
175 * radix specified by the second argument. The characters in the
176 * string must all be digits, of the specified radix (as
177 * determined by whether {@link java.lang.Character#digit(char,
178 * int)} returns a nonnegative value) except that the first
179 * character may be an ASCII minus sign {@code '-'}
180 * ({@code '\u005Cu002D'}) to indicate a negative value or an
181 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
182 * indicate a positive value. The resulting {@code byte} value is
183 * returned.
184 *
185 * <p>An exception of type {@code NumberFormatException} is
186 * thrown if any of the following situations occurs:
187 * <ul>
188 * <li> The first argument is {@code null} or is a string of
189 * length zero.
190 *
|