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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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1+/*
2+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4+ *
5+ * This code is free software; you can redistribute it and/or modify it
6+ * under the terms of the GNU General Public License version 2 only, as
7+ * published by the Free Software Foundation. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
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.util;
27+
28+import java.security.*;
29+
30+/**
31+ * A class that represents an immutable universally unique identifier (UUID).
32+ * A UUID represents a 128-bit value.
33+ *
34+ * <p> There exist different variants of these global identifiers. The methods
35+ * of this class are for manipulating the Leach-Salz variant, although the
36+ * constructors allow the creation of any variant of UUID (described below).
37+ *
38+ * <p> The layout of a variant 2 (Leach-Salz) UUID is as follows:
39+ *
40+ * The most significant long consists of the following unsigned fields:
41+ * <pre>
42+ * 0xFFFFFFFF00000000 time_low
43+ * 0x00000000FFFF0000 time_mid
44+ * 0x000000000000F000 version
45+ * 0x0000000000000FFF time_hi
46+ * </pre>
47+ * The least significant long consists of the following unsigned fields:
48+ * <pre>
49+ * 0xC000000000000000 variant
50+ * 0x3FFF000000000000 clock_seq
51+ * 0x0000FFFFFFFFFFFF node
52+ * </pre>
53+ *
54+ * <p> The variant field contains a value which identifies the layout of the
55+ * {@code UUID}. The bit layout described above is valid only for a {@code
56+ * UUID} with a variant value of 2, which indicates the Leach-Salz variant.
57+ *
58+ * <p> The version field holds a value that describes the type of this {@code
59+ * UUID}. There are four different basic types of UUIDs: time-based, DCE
60+ * security, name-based, and randomly generated UUIDs. These types have a
61+ * version value of 1, 2, 3 and 4, respectively.
62+ *
63+ * <p> For more information including algorithms used to create {@code UUID}s,
64+ * see <a href="http://www.ietf.org/rfc/rfc4122.txt"> <i>RFC&nbsp;4122: A
65+ * Universally Unique IDentifier (UUID) URN Namespace</i></a>, section 4.2
66+ * &quot;Algorithms for Creating a Time-Based UUID&quot;.
67+ *
68+ * @since 1.5
69+ */
70+public final class UUID implements java.io.Serializable, Comparable<UUID> {
71+
72+ /**
73+ * Explicit serialVersionUID for interoperability.
74+ */
75+ private static final long serialVersionUID = -4856846361193249489L;
76+
77+ /*
78+ * The most significant 64 bits of this UUID.
79+ *
80+ * @serial
81+ */
82+ private final long mostSigBits;
83+
84+ /*
85+ * The least significant 64 bits of this UUID.
86+ *
87+ * @serial
88+ */
89+ private final long leastSigBits;
90+
91+ /*
92+ * The random number generator used by this class to create random
93+ * based UUIDs.
94+ */
95+ private static volatile SecureRandom numberGenerator = null;
96+
97+ // Constructors and Factories
98+
99+ /*
100+ * Private constructor which uses a byte array to construct the new UUID.
101+ */
102+ private UUID(byte[] data) {
103+ long msb = 0;
104+ long lsb = 0;
105+ assert data.length == 16 : "data must be 16 bytes in length";
106+ for (int i=0; i<8; i++)
107+ msb = (msb << 8) | (data[i] & 0xff);
108+ for (int i=8; i<16; i++)
109+ lsb = (lsb << 8) | (data[i] & 0xff);
110+ this.mostSigBits = msb;
111+ this.leastSigBits = lsb;
112+ }
113+
114+ /**
115+ * Constructs a new {@code UUID} using the specified data. {@code
116+ * mostSigBits} is used for the most significant 64 bits of the {@code
117+ * UUID} and {@code leastSigBits} becomes the least significant 64 bits of
118+ * the {@code UUID}.
119+ *
120+ * @param mostSigBits
121+ * The most significant bits of the {@code UUID}
122+ *
123+ * @param leastSigBits
124+ * The least significant bits of the {@code UUID}
125+ */
126+ public UUID(long mostSigBits, long leastSigBits) {
127+ this.mostSigBits = mostSigBits;
128+ this.leastSigBits = leastSigBits;
129+ }
130+
131+ /**
132+ * Static factory to retrieve a type 4 (pseudo randomly generated) UUID.
133+ *
134+ * The {@code UUID} is generated using a cryptographically strong pseudo
135+ * random number generator.
136+ *
137+ * @return A randomly generated {@code UUID}
138+ */
139+ public static UUID randomUUID() {
140+ SecureRandom ng = numberGenerator;
141+ if (ng == null) {
142+ numberGenerator = ng = new SecureRandom();
143+ }
144+
145+ byte[] randomBytes = new byte[16];
146+ ng.nextBytes(randomBytes);
147+ randomBytes[6] &= 0x0f; /* clear version */
148+ randomBytes[6] |= 0x40; /* set to version 4 */
149+ randomBytes[8] &= 0x3f; /* clear variant */
150+ randomBytes[8] |= 0x80; /* set to IETF variant */
151+ return new UUID(randomBytes);
152+ }
153+
154+ /**
155+ * Static factory to retrieve a type 3 (name based) {@code UUID} based on
156+ * the specified byte array.
157+ *
158+ * @param name
159+ * A byte array to be used to construct a {@code UUID}
160+ *
161+ * @return A {@code UUID} generated from the specified array
162+ */
163+ public static UUID nameUUIDFromBytes(byte[] name) {
164+ MessageDigest md;
165+ try {
166+ md = MessageDigest.getInstance("MD5");
167+ } catch (NoSuchAlgorithmException nsae) {
168+ throw new InternalError("MD5 not supported");
169+ }
170+ byte[] md5Bytes = md.digest(name);
171+ md5Bytes[6] &= 0x0f; /* clear version */
172+ md5Bytes[6] |= 0x30; /* set to version 3 */
173+ md5Bytes[8] &= 0x3f; /* clear variant */
174+ md5Bytes[8] |= 0x80; /* set to IETF variant */
175+ return new UUID(md5Bytes);
176+ }
177+
178+ /**
179+ * Creates a {@code UUID} from the string standard representation as
180+ * described in the {@link #toString} method.
181+ *
182+ * @param name
183+ * A string that specifies a {@code UUID}
184+ *
185+ * @return A {@code UUID} with the specified value
186+ *
187+ * @throws IllegalArgumentException
188+ * If name does not conform to the string representation as
189+ * described in {@link #toString}
190+ *
191+ */
192+ public static UUID fromString(String name) {
193+ String[] components = name.split("-");
194+ if (components.length != 5)
195+ throw new IllegalArgumentException("Invalid UUID string: "+name);
196+ for (int i=0; i<5; i++)
197+ components[i] = "0x"+components[i];
198+
199+ long mostSigBits = Long.decode(components[0]).longValue();
200+ mostSigBits <<= 16;
201+ mostSigBits |= Long.decode(components[1]).longValue();
202+ mostSigBits <<= 16;
203+ mostSigBits |= Long.decode(components[2]).longValue();
204+
205+ long leastSigBits = Long.decode(components[3]).longValue();
206+ leastSigBits <<= 48;
207+ leastSigBits |= Long.decode(components[4]).longValue();
208+
209+ return new UUID(mostSigBits, leastSigBits);
210+ }
211+
212+ // Field Accessor Methods
213+
214+ /**
215+ * Returns the least significant 64 bits of this UUID's 128 bit value.
216+ *
217+ * @return The least significant 64 bits of this UUID's 128 bit value
218+ */
219+ public long getLeastSignificantBits() {
220+ return leastSigBits;
221+ }
222+
223+ /**
224+ * Returns the most significant 64 bits of this UUID's 128 bit value.
225+ *
226+ * @return The most significant 64 bits of this UUID's 128 bit value
227+ */
228+ public long getMostSignificantBits() {
229+ return mostSigBits;
230+ }
231+
232+ /**
233+ * The version number associated with this {@code UUID}. The version
234+ * number describes how this {@code UUID} was generated.
235+ *
236+ * The version number has the following meaning:
237+ * <p><ul>
238+ * <li>1 Time-based UUID
239+ * <li>2 DCE security UUID
240+ * <li>3 Name-based UUID
241+ * <li>4 Randomly generated UUID
242+ * </ul>
243+ *
244+ * @return The version number of this {@code UUID}
245+ */
246+ public int version() {
247+ // Version is bits masked by 0x000000000000F000 in MS long
248+ return (int)((mostSigBits >> 12) & 0x0f);
249+ }
250+
251+ /**
252+ * The variant number associated with this {@code UUID}. The variant
253+ * number describes the layout of the {@code UUID}.
254+ *
255+ * The variant number has the following meaning:
256+ * <p><ul>
257+ * <li>0 Reserved for NCS backward compatibility
258+ * <li>2 The Leach-Salz variant (used by this class)
259+ * <li>6 Reserved, Microsoft Corporation backward compatibility
260+ * <li>7 Reserved for future definition
261+ * </ul>
262+ *
263+ * @return The variant number of this {@code UUID}
264+ */
265+ public int variant() {
266+ // This field is composed of a varying number of bits.
267+ // 0 - - Reserved for NCS backward compatibility
268+ // 1 0 - The Leach-Salz variant (used by this class)
269+ // 1 1 0 Reserved, Microsoft backward compatibility
270+ // 1 1 1 Reserved for future definition.
271+ return (int) ((leastSigBits >>> (64 - (leastSigBits >>> 62)))
272+ & (leastSigBits >> 63));
273+ }
274+
275+ /**
276+ * The timestamp value associated with this UUID.
277+ *
278+ * <p> The 60 bit timestamp value is constructed from the time_low,
279+ * time_mid, and time_hi fields of this {@code UUID}. The resulting
280+ * timestamp is measured in 100-nanosecond units since midnight,
281+ * October 15, 1582 UTC.
282+ *
283+ * <p> The timestamp value is only meaningful in a time-based UUID, which
284+ * has version type 1. If this {@code UUID} is not a time-based UUID then
285+ * this method throws UnsupportedOperationException.
286+ *
287+ * @throws UnsupportedOperationException
288+ * If this UUID is not a version 1 UUID
289+ */
290+ public long timestamp() {
291+ if (version() != 1) {
292+ throw new UnsupportedOperationException("Not a time-based UUID");
293+ }
294+
295+ return (mostSigBits & 0x0FFFL) << 48
296+ | ((mostSigBits >> 16) & 0x0FFFFL) << 32
297+ | mostSigBits >>> 32;
298+ }
299+
300+ /**
301+ * The clock sequence value associated with this UUID.
302+ *
303+ * <p> The 14 bit clock sequence value is constructed from the clock
304+ * sequence field of this UUID. The clock sequence field is used to
305+ * guarantee temporal uniqueness in a time-based UUID.
306+ *
307+ * <p> The {@code clockSequence} value is only meaningful in a time-based
308+ * UUID, which has version type 1. If this UUID is not a time-based UUID
309+ * then this method throws UnsupportedOperationException.
310+ *
311+ * @return The clock sequence of this {@code UUID}
312+ *
313+ * @throws UnsupportedOperationException
314+ * If this UUID is not a version 1 UUID
315+ */
316+ public int clockSequence() {
317+ if (version() != 1) {
318+ throw new UnsupportedOperationException("Not a time-based UUID");
319+ }
320+
321+ return (int)((leastSigBits & 0x3FFF000000000000L) >>> 48);
322+ }
323+
324+ /**
325+ * The node value associated with this UUID.
326+ *
327+ * <p> The 48 bit node value is constructed from the node field of this
328+ * UUID. This field is intended to hold the IEEE 802 address of the machine
329+ * that generated this UUID to guarantee spatial uniqueness.
330+ *
331+ * <p> The node value is only meaningful in a time-based UUID, which has
332+ * version type 1. If this UUID is not a time-based UUID then this method
333+ * throws UnsupportedOperationException.
334+ *
335+ * @return The node value of this {@code UUID}
336+ *
337+ * @throws UnsupportedOperationException
338+ * If this UUID is not a version 1 UUID
339+ */
340+ public long node() {
341+ if (version() != 1) {
342+ throw new UnsupportedOperationException("Not a time-based UUID");
343+ }
344+
345+ return leastSigBits & 0x0000FFFFFFFFFFFFL;
346+ }
347+
348+ // Object Inherited Methods
349+
350+ /**
351+ * Returns a {@code String} object representing this {@code UUID}.
352+ *
353+ * <p> The UUID string representation is as described by this BNF:
354+ * <blockquote><pre>
355+ * {@code
356+ * UUID = <time_low> "-" <time_mid> "-"
357+ * <time_high_and_version> "-"
358+ * <variant_and_sequence> "-"
359+ * <node>
360+ * time_low = 4*<hexOctet>
361+ * time_mid = 2*<hexOctet>
362+ * time_high_and_version = 2*<hexOctet>
363+ * variant_and_sequence = 2*<hexOctet>
364+ * node = 6*<hexOctet>
365+ * hexOctet = <hexDigit><hexDigit>
366+ * hexDigit =
367+ * "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
368+ * | "a" | "b" | "c" | "d" | "e" | "f"
369+ * | "A" | "B" | "C" | "D" | "E" | "F"
370+ * }</pre></blockquote>
371+ *
372+ * @return A string representation of this {@code UUID}
373+ */
374+ public String toString() {
375+ return (digits(mostSigBits >> 32, 8) + "-" +
376+ digits(mostSigBits >> 16, 4) + "-" +
377+ digits(mostSigBits, 4) + "-" +
378+ digits(leastSigBits >> 48, 4) + "-" +
379+ digits(leastSigBits, 12));
380+ }
381+
382+ /** Returns val represented by the specified number of hex digits. */
383+ private static String digits(long val, int digits) {
384+ long hi = 1L << (digits * 4);
385+ return Long.toHexString(hi | (val & (hi - 1))).substring(1);
386+ }
387+
388+ /**
389+ * Returns a hash code for this {@code UUID}.
390+ *
391+ * @return A hash code value for this {@code UUID}
392+ */
393+ public int hashCode() {
394+ long hilo = mostSigBits ^ leastSigBits;
395+ return ((int)(hilo >> 32)) ^ (int) hilo;
396+ }
397+
398+ /**
399+ * Compares this object to the specified object. The result is {@code
400+ * true} if and only if the argument is not {@code null}, is a {@code UUID}
401+ * object, has the same variant, and contains the same value, bit for bit,
402+ * as this {@code UUID}.
403+ *
404+ * @param obj
405+ * The object to be compared
406+ *
407+ * @return {@code true} if the objects are the same; {@code false}
408+ * otherwise
409+ */
410+ public boolean equals(Object obj) {
411+ if ((null == obj) || (obj.getClass() != UUID.class))
412+ return false;
413+ UUID id = (UUID)obj;
414+ return (mostSigBits == id.mostSigBits &&
415+ leastSigBits == id.leastSigBits);
416+ }
417+
418+ // Comparison Operations
419+
420+ /**
421+ * Compares this UUID with the specified UUID.
422+ *
423+ * <p> The first of two UUIDs is greater than the second if the most
424+ * significant field in which the UUIDs differ is greater for the first
425+ * UUID.
426+ *
427+ * @param val
428+ * {@code UUID} to which this {@code UUID} is to be compared
429+ *
430+ * @return -1, 0 or 1 as this {@code UUID} is less than, equal to, or
431+ * greater than {@code val}
432+ *
433+ */
434+ public int compareTo(UUID val) {
435+ // The ordering is intentionally set up so that the UUIDs
436+ // can simply be numerically compared as two numbers
437+ return (this.mostSigBits < val.mostSigBits ? -1 :
438+ (this.mostSigBits > val.mostSigBits ? 1 :
439+ (this.leastSigBits < val.leastSigBits ? -1 :
440+ (this.leastSigBits > val.leastSigBits ? 1 :
441+ 0))));
442+ }
443+}