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.VM;
30 import jdk.internal.util.DecimalDigits;
31 import jdk.internal.vm.annotation.ForceInline;
32 import jdk.internal.vm.annotation.IntrinsicCandidate;
33 import jdk.internal.vm.annotation.Stable;
34
35 import java.lang.annotation.Native;
36 import java.lang.constant.Constable;
37 import java.lang.constant.ConstantDesc;
38 import java.lang.invoke.MethodHandles;
39 import java.util.Objects;
40 import java.util.Optional;
41
42 import static java.lang.Character.digit;
43 import static java.lang.String.COMPACT_STRINGS;
44 import static java.lang.String.LATIN1;
45 import static java.lang.String.UTF16;
46
47 /**
48 * The {@code Integer} class is the {@linkplain
49 * java.lang##wrapperClass wrapper class} for values of the primitive
50 * type {@code int}. An object of type {@code Integer} contains a
51 * single field whose type is {@code int}.
52 *
53 * <p>In addition, this class provides several methods for converting
54 * an {@code int} to a {@code String} and a {@code String} to an
55 * {@code int}, as well as other constants and methods useful when
56 * dealing with an {@code int}.
57 *
58 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
59 * class; programmers should treat instances that are
60 * {@linkplain #equals(Object) equal} as interchangeable and should not
61 * use instances for synchronization, or unpredictable behavior may
62 * occur. For example, in a future release, synchronization may fail.
63 *
64 * <p>Implementation note: The implementations of the "bit twiddling"
65 * methods (such as {@link #highestOneBit(int) highestOneBit} and
66 * {@link #numberOfTrailingZeros(int) numberOfTrailingZeros}) are
67 * based on material from Henry S. Warren, Jr.'s <cite>Hacker's
68 * Delight</cite>, (Addison Wesley, 2002) and <cite>Hacker's
69 * Delight, Second Edition</cite>, (Pearson Education, 2013).
70 *
71 * @author Lee Boynton
72 * @author Arthur van Hoff
73 * @author Josh Bloch
74 * @author Joseph D. Darcy
75 * @since 1.0
76 */
77 @jdk.internal.ValueBased
78 public final class Integer extends Number
79 implements Comparable<Integer>, Constable, ConstantDesc {
80 /**
81 * A constant holding the minimum value an {@code int} can
82 * have, -2<sup>31</sup>.
83 */
84 @Native public static final int MIN_VALUE = 0x80000000;
85
86 /**
87 * A constant holding the maximum value an {@code int} can
88 * have, 2<sup>31</sup>-1.
89 */
90 @Native public static final int MAX_VALUE = 0x7fffffff;
91
92 /**
93 * The {@code Class} instance representing the primitive type
94 * {@code int}.
95 *
96 * @since 1.1
969 c[i] = archivedCache[i];
970 assert j == archivedCache[i];
971 j++;
972 }
973 // Fill the rest of the cache.
974 for (int i = archivedSize; i < size; i++) {
975 c[i] = new Integer(j++);
976 }
977 archivedCache = c;
978 }
979 cache = archivedCache;
980 // range [-128, 127] must be interned (JLS7 5.1.7)
981 assert IntegerCache.high >= 127;
982 }
983
984 private IntegerCache() {}
985 }
986
987 /**
988 * Returns an {@code Integer} instance representing the specified
989 * {@code int} value. If a new {@code Integer} instance is not
990 * required, this method should generally be used in preference to
991 * the constructor {@link #Integer(int)}, as this method is likely
992 * to yield significantly better space and time performance by
993 * caching frequently requested values.
994 *
995 * This method will always cache values in the range -128 to 127,
996 * inclusive, and may cache other values outside of this range.
997 *
998 * @param i an {@code int} value.
999 * @return an {@code Integer} instance representing {@code i}.
1000 * @since 1.5
1001 */
1002 @IntrinsicCandidate
1003 public static Integer valueOf(int i) {
1004 if (i >= IntegerCache.low && i <= IntegerCache.high)
1005 return IntegerCache.cache[i + (-IntegerCache.low)];
1006 return new Integer(i);
1007 }
1008
1009 /**
1010 * The value of the {@code Integer}.
1011 *
1012 * @serial
1013 */
1014 private final int value;
1015
1016 /**
1017 * Constructs a newly allocated {@code Integer} object that
1018 * represents the specified {@code int} value.
1019 *
1020 * @param value the value to be represented by the
1021 * {@code Integer} object.
1022 *
1023 * @deprecated
1024 * It is rarely appropriate to use this constructor. The static factory
1025 * {@link #valueOf(int)} is generally a better choice, as it is
|
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.misc.VM;
31 import jdk.internal.util.DecimalDigits;
32 import jdk.internal.value.DeserializeConstructor;
33 import jdk.internal.vm.annotation.ForceInline;
34 import jdk.internal.vm.annotation.IntrinsicCandidate;
35 import jdk.internal.vm.annotation.Stable;
36
37 import java.lang.annotation.Native;
38 import java.lang.constant.Constable;
39 import java.lang.constant.ConstantDesc;
40 import java.lang.invoke.MethodHandles;
41 import java.util.Objects;
42 import java.util.Optional;
43
44 import static java.lang.Character.digit;
45 import static java.lang.String.COMPACT_STRINGS;
46 import static java.lang.String.LATIN1;
47 import static java.lang.String.UTF16;
48
49 /**
50 * The {@code Integer} class is the {@linkplain
51 * java.lang##wrapperClass wrapper class} for values of the primitive
52 * type {@code int}. An object of type {@code Integer} contains a
53 * single field whose type is {@code int}.
54 *
55 * <p>In addition, this class provides several methods for converting
56 * an {@code int} to a {@code String} and a {@code String} to an
57 * {@code int}, as well as other constants and methods useful when
58 * dealing with an {@code int}.
59 *
60 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
61 * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
62 * as interchangeable and should not use instances for synchronization, mutexes, or
63 * with {@linkplain java.lang.ref.Reference object references}.
64 *
65 * <div class="preview-block">
66 * <div class="preview-comment">
67 * When preview features are enabled, {@code Integer} is a {@linkplain Class#isValue value class}.
68 * Use of value class instances for synchronization, mutexes, or with
69 * {@linkplain java.lang.ref.Reference object references} result in
70 * {@link IdentityException}.
71 * </div>
72 * </div>
73 *
74 * <p>Implementation note: The implementations of the "bit twiddling"
75 * methods (such as {@link #highestOneBit(int) highestOneBit} and
76 * {@link #numberOfTrailingZeros(int) numberOfTrailingZeros}) are
77 * based on material from Henry S. Warren, Jr.'s <cite>Hacker's
78 * Delight</cite>, (Addison Wesley, 2002) and <cite>Hacker's
79 * Delight, Second Edition</cite>, (Pearson Education, 2013).
80 *
81 * @author Lee Boynton
82 * @author Arthur van Hoff
83 * @author Josh Bloch
84 * @author Joseph D. Darcy
85 * @since 1.0
86 */
87 @jdk.internal.MigratedValueClass
88 @jdk.internal.ValueBased
89 public final class Integer extends Number
90 implements Comparable<Integer>, Constable, ConstantDesc {
91 /**
92 * A constant holding the minimum value an {@code int} can
93 * have, -2<sup>31</sup>.
94 */
95 @Native public static final int MIN_VALUE = 0x80000000;
96
97 /**
98 * A constant holding the maximum value an {@code int} can
99 * have, 2<sup>31</sup>-1.
100 */
101 @Native public static final int MAX_VALUE = 0x7fffffff;
102
103 /**
104 * The {@code Class} instance representing the primitive type
105 * {@code int}.
106 *
107 * @since 1.1
980 c[i] = archivedCache[i];
981 assert j == archivedCache[i];
982 j++;
983 }
984 // Fill the rest of the cache.
985 for (int i = archivedSize; i < size; i++) {
986 c[i] = new Integer(j++);
987 }
988 archivedCache = c;
989 }
990 cache = archivedCache;
991 // range [-128, 127] must be interned (JLS7 5.1.7)
992 assert IntegerCache.high >= 127;
993 }
994
995 private IntegerCache() {}
996 }
997
998 /**
999 * Returns an {@code Integer} instance representing the specified
1000 * {@code int} value.
1001 * <div class="preview-block">
1002 * <div class="preview-comment">
1003 * <p>
1004 * - When preview features are NOT enabled, {@code Integer} is an identity class.
1005 * If a new {@code Integer} instance is not
1006 * required, this method should generally be used in preference to
1007 * the constructor {@link #Integer(int)}, as this method is likely
1008 * to yield significantly better space and time performance by
1009 * caching frequently requested values.
1010 * This method will always cache values in the range -128 to 127,
1011 * inclusive, and may cache other values outside of this range.
1012 * </p>
1013 * <p>
1014 * - When preview features are enabled, {@code Integer} is a {@linkplain Class#isValue value class}.
1015 * The {@code valueOf} behavior is the same as invoking the constructor,
1016 * whether cached or not.
1017 * </p>
1018 * </div>
1019 * </div>
1020 *
1021 * @param i an {@code int} value.
1022 * @return an {@code Integer} instance representing {@code i}.
1023 * @since 1.5
1024 */
1025 @IntrinsicCandidate
1026 @DeserializeConstructor
1027 public static Integer valueOf(int i) {
1028 if (!PreviewFeatures.isEnabled()) {
1029 if (i >= IntegerCache.low && i <= IntegerCache.high)
1030 return IntegerCache.cache[i + (-IntegerCache.low)];
1031 }
1032 return new Integer(i);
1033 }
1034
1035 /**
1036 * The value of the {@code Integer}.
1037 *
1038 * @serial
1039 */
1040 private final int value;
1041
1042 /**
1043 * Constructs a newly allocated {@code Integer} object that
1044 * represents the specified {@code int} value.
1045 *
1046 * @param value the value to be represented by the
1047 * {@code Integer} object.
1048 *
1049 * @deprecated
1050 * It is rarely appropriate to use this constructor. The static factory
1051 * {@link #valueOf(int)} is generally a better choice, as it is
|