I missed the IETF license clause that requires quoting from IETF documents to carry the full IETF copyright notice paragraph. This patch applies the (c) disclaimer paragraph as specified by the IETF copy license.
Also removed the @author tag. Forthcoming patch changes this class to an interface. Index: UuidClock.java =================================================================== RCS file: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/ uuid/UuidClock.java,v retrieving revision 1.1 diff -u -r1.1 UuidClock.java --- UuidClock.java 24 Dec 2003 08:59:45 -0000 1.1 +++ UuidClock.java 29 Dec 2003 23:28:22 -0000 @@ -1,224 +1,249 @@ -/* - * $Header: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/ uuid/UuidClock.java,v 1.1 2003/12/24 08:59:45 psteitz Exp $ - * ==================================================================== - * - * The Apache Software License, Version 1.1 - * - * Copyright (c) 2001-2003 The Apache Software Foundation. All rights - * reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * 3. The end-user documentation included with the redistribution, if - * any, must include the following acknowledgement: - * "This product includes software developed by the - * Apache Software Foundation (http://www.apache.org/)." - * Alternately, this acknowledgement may appear in the software itself, - * if and wherever such third-party acknowledgements normally appear. - * - * 4. The names "The Jakarta Project", "Commons", and "Apache Software - * Foundation" must not be used to endorse or promote products derived - * from this software without prior written permission. For written - * permission, please contact [EMAIL PROTECTED] - * - * 5. Products derived from this software may not be called "Apache" - * nor may "Apache" appear in their names without prior written - * permission of the Apache Software Foundation. - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR - * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF - * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND - * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT - * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * ==================================================================== - * - * This software consists of voluntary contributions made by many - * individuals on behalf of the Apache Software Foundation. For more - * information on the Apache Software Foundation, please see - * <http://www.apache.org/>. - * - */ - -package org.apache.commons.uid.uuid; - -/** - * UuidClock.java provides a timing mechanism for returning the current time in - * 100-nano second intervals since 00:00:00.00, 15 October 1582 - * - * As described below this is useful for generating Version 1 UUIDs - * - * For more information regarding the IETF Draft Uuid specification - * see http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-01.txt - * - * Selected segements of Draft pertaining to this class: - * - * ==================================================================== - * Timestamp - * The timestamp is a 60 bit value. For Uuid version 1, this is - * represented by Coordinated Universal Time (UTC) as a count of 100- - * nanosecond intervals since 00:00:00.00, 15 October 1582 (the date of - * Gregorian reform to the Christian calendar). - * - * Clock Adjustment - * UUIDs may be created at a rate greater than the system clock resolution. - * Therefore, the system must also maintain an adjustment value to be added to - * the lower-order bits of the time. Logically, each time the system clock - * ticks, the adjustment value is cleared. Every time a UUID is generated, - * the current adjustment value is read and incremented atomically, then added - * to the UTC time field of the UUID. - * - * Clock Overrun - * The 100 nanosecond granularity of time should prove sufficient even for - * bursts of UUID creation in the next generation of high-performance - * multiprocessors. If a system overruns the clock adjustment by requesting - * too many UUIDs within a single system clock tick, the UUID service may - * raise an exception, handled in a system or process-dependent manner - * either by: - * terminating the request - * reissuing the request until it succeeds - * stalling the UUID generator until the system clock catches up. - * - * If the processors overrun the UUID generation frequently, additional node - * identifiers and clocks may need to be added. - * ==================================================================== - * - * @version $Revision: 1.1 $ $Date: 2003/12/24 08:59:45 $ - * @author Tim Reilly - */ - -public class UuidClock extends Thread { - - /** Default life of the UuidClock thread in milliseconds */ - public static final long DEFAULT_THREAD_LIFE = 200; - - /** Offset from GregorianCalendar Change over to Jan 1 1970 00:00:00.00 */ - public static final long GREGORIAN_CHANGE_OFFSET = 12219292800000L; - - /** Maximum ticks per millisecond interval */ - public static final long TICKS_PER_MILLI = 10000L; - - /** Life time of the clock thread in milliseconds */ - private static long threadLife = DEFAULT_THREAD_LIFE; - - /** Singleton instance of the UuidClock */ - private static UuidClock clock = null; - - /** The counter for nanoseconds generated during this system interval(ms) */ - private int generatedThisMilli; - - /** The current time in milliseconds held in this clock thread. */ - private long currentTimeMillis; - - /** Time when the clock thread should die */ - private long expires = threadLife; - - /** - * Private constructor for clock implementation. Utilizes a single thread to - * increment the clock every milli seconds this should be more - * accurate than System.currentTimeMillis() as described in - * the javaworld article: - * http://www.javaworld.com/javaworld/javaqa/2003-01/01-qa-0110-timing.html - */ - - private UuidClock() { - setDaemon(true); - setPriority(Thread.MAX_PRIORITY); - currentTimeMillis = System.currentTimeMillis(); - start(); - } - - /** - * Returns the thread life in milliseconds. If the clock thread is not - * accessed within this time span the thread will die off. - * - * @return thread life time span in milliseconds - */ - public static long getThreadLife() { - return UuidClock.threadLife; - } - - /** - * @param threadLife milliseconds this thread should live for. Each - * call to getCurrentTime resets the expiration time value. - */ - public static void setThreadLife(long threadLife) { - UuidClock.threadLife = threadLife; - } - - /** - * Threads run method that increments the clock and resets the generated - * nano seconds counter. - */ - public void run() { - try { - while (--expires >= 0) { - Thread.sleep(1); - currentTimeMillis++; - generatedThisMilli = 1; - } - } catch (InterruptedException e) { - System.out.println("UuidClock thread interrupted"); - } - } - - /** - * Returns the internal time milliseconds for the UuidClock instance - * @return the clock threads current time in milliseconds - */ - private long getCurrentTimeMillis() { - return currentTimeMillis; - } - - /** - * Returns the current time as described in the clock resolution and - * timestamp sections of the uuid specification. - * - * @return the current time in 100-nano second intervals (simulated) - */ - private long currentTime() { - this.expires = threadLife; - // Stall until counter is reset to limit only 10000 intervals per - // millisecond interval - while (generatedThisMilli > TICKS_PER_MILLI) { - //wait for thread to reset - } - - long currentTime = - ((currentTimeMillis + GREGORIAN_CHANGE_OFFSET) * TICKS_PER_MILLI); - - return currentTime + (generatedThisMilli++); - } - - /** - * Static method returns the clocks current time in 100-nanosecond intervals - * since the Gregorian calander change. Calendar.GREGORIAN_OFFSET - * - * @return Coordinated Universal Time (UTC) as a count of 100- nanosecond - * intervals since 00:00:00.00, 15 October 1582 - */ - public static synchronized long getCurrentTime() { - if (clock == null || !clock.isAlive()) { - clock = null; - clock = new UuidClock(); - } - return clock.currentTime(); - } - -} +/* + * $Header: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/ uuid/UuidClock.java,v 1.1 2003/12/24 08:59:45 psteitz Exp $ + * ==================================================================== + * + * The Apache Software License, Version 1.1 + * + * Copyright (c) 2001-2003 The Apache Software Foundation. All rights + * reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. The end-user documentation included with the redistribution, if + * any, must include the following acknowledgement: + * "This product includes software developed by the + * Apache Software Foundation (http://www.apache.org/)." + * Alternately, this acknowledgement may appear in the software itself, + * if and wherever such third-party acknowledgements normally appear. + * + * 4. The names "The Jakarta Project", "Commons", and "Apache Software + * Foundation" must not be used to endorse or promote products derived + * from this software without prior written permission. For written + * permission, please contact [EMAIL PROTECTED] + * + * 5. Products derived from this software may not be called "Apache" + * nor may "Apache" appear in their names without prior written + * permission of the Apache Software Foundation. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * ==================================================================== + * + * This software consists of voluntary contributions made by many + * individuals on behalf of the Apache Software Foundation. For more + * information on the Apache Software Foundation, please see + * <http://www.apache.org/>. + * + */ + +package org.apache.commons.uid.uuid; + +/** + * UuidClock.java provides a timing mechanism for returning the current time in + * 100-nano second intervals since 00:00:00.00, 15 October 1582 + * + * As described below this is useful for generating Version 1 UUIDs + * + * For more information regarding the IETF Draft Uuid specification + * see http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-01.txt + * + * Selected quotes from IETF document pertaining to this class: + * + * ==================================================================== + * -Timestamp- + * "The timestamp is a 60 bit value. For Uuid version 1, this is + * represented by Coordinated Universal Time (UTC) as a count of 100- + * nanosecond intervals since 00:00:00.00, 15 October 1582 (the date of + * Gregorian reform to the Christian calendar)." + * + * -Clock Adjustment- + * "UUIDs may be created at a rate greater than the system clock resolution. + * Therefore, the system must also maintain an adjustment value to be added to + * the lower-order bits of the time. Logically, each time the system clock + * ticks, the adjustment value is cleared. Every time a UUID is generated, + * the current adjustment value is read and incremented atomically, then added + * to the UTC time field of the UUID." + * + * -Clock Overrun- + * "The 100 nanosecond granularity of time should prove sufficient even for + * bursts of UUID creation in the next generation of high-performance + * multiprocessors. If a system overruns the clock adjustment by requesting + * too many UUIDs within a single system clock tick, the UUID service may + * raise an exception, handled in a system or process-dependent manner + * either by: + * terminating the request + * reissuing the request until it succeeds + * stalling the UUID generator until the system clock catches up. + * ... + * If the processors overrun the UUID generation frequently, additional node + * identifiers and clocks may need to be added." + * + * - The above quotations are protected under the following copyright notice - + * Copyright (C) The Internet Society (2003). All Rights Reserved. + * This document and translations of it may be copied and furnished to + * others, and derivative works that comment on or otherwise explain it + * or assist in its implementation may be prepared, copied, published + * and distributed, in whole or in part, without restriction of any + * kind, provided that the above copyright notice and this paragraph are + * included on all such copies and derivative works. However, this + * document itself may not be modified in any way, such as by removing + * the copyright notice or references to the Internet Society or other + * Internet organizations, except as needed for the purpose of + * developing Internet standards in which case the procedures for + * copyrights defined in the Internet Standards process must be + * followed, or as required to translate it into languages other than + * English. + * The limited permissions granted above are perpetual and will not be + * revoked by the Internet Society or its successors or assignees. + * This document and the information contained herein is provided on an + * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + * + * ==================================================================== + * + * @version $Revision: 1.1 $ $Date: 2003/12/24 08:59:45 $ + * + */ + +public class UuidClock extends Thread { + + /** Default life of the UuidClock thread in milliseconds */ + public static final long DEFAULT_THREAD_LIFE = 200; + + /** Offset from GregorianCalendar Change over to Jan 1 1970 00:00:00.00 */ + public static final long GREGORIAN_CHANGE_OFFSET = 12219292800000L; + + /** Maximum ticks per millisecond interval */ + public static final long TICKS_PER_MILLI = 10000L; + + /** Life time of the clock thread in milliseconds */ + private static long threadLife = DEFAULT_THREAD_LIFE; + + /** Singleton instance of the UuidClock */ + private static UuidClock clock = null; + + /** The counter for nanoseconds generated during this system interval(ms) */ + private int generatedThisMilli; + + /** The current time in milliseconds held in this clock thread. */ + private long currentTimeMillis; + + /** Time when the clock thread should die */ + private long expires = threadLife; + + /** + * Private constructor for clock implementation. Utilizes a single thread to + * increment the clock every milli seconds this should be more + * accurate than System.currentTimeMillis() as described in + * the javaworld article: + * http://www.javaworld.com/javaworld/javaqa/2003-01/01-qa-0110-timing.html + */ + + private UuidClock() { + setDaemon(true); + setPriority(Thread.MAX_PRIORITY); + currentTimeMillis = System.currentTimeMillis(); + start(); + } + + /** + * Returns the thread life in milliseconds. If the clock thread is not + * accessed within this time span the thread will die off. + * + * @return thread life time span in milliseconds + */ + public static long getThreadLife() { + return UuidClock.threadLife; + } + + /** + * @param threadLife milliseconds this thread should live for. Each + * call to getCurrentTime resets the expiration time value. + */ + public static void setThreadLife(long threadLife) { + UuidClock.threadLife = threadLife; + } + + /** + * Threads run method that increments the clock and resets the generated + * nano seconds counter. + */ + public void run() { + try { + while (--expires >= 0) { + Thread.sleep(1); + currentTimeMillis++; + generatedThisMilli = 1; + } + } catch (InterruptedException e) { + System.out.println("UuidClock thread interrupted"); + } + } + + /** + * Returns the internal time milliseconds for the UuidClock instance + * @return the clock threads current time in milliseconds + */ + private long getCurrentTimeMillis() { + return currentTimeMillis; + } + + /** + * Returns the current time as described in the clock resolution and + * timestamp sections of the uuid specification. + * + * @return the current time in 100-nano second intervals (simulated) + */ + private long currentTime() { + this.expires = threadLife; + // Stall until counter is reset to limit only 10000 intervals per + // millisecond interval + while (generatedThisMilli > TICKS_PER_MILLI) { + //wait for thread to reset + } + + long currentTime = + ((currentTimeMillis + GREGORIAN_CHANGE_OFFSET) * TICKS_PER_MILLI); + + return currentTime + (generatedThisMilli++); + } + + /** + * Static method returns the clocks current time in 100-nanosecond intervals + * since the Gregorian calander change. Calendar.GREGORIAN_OFFSET + * + * @return Coordinated Universal Time (UTC) as a count of 100- nanosecond + * intervals since 00:00:00.00, 15 October 1582 + */ + public static synchronized long getCurrentTime() { + if (clock == null || !clock.isAlive()) { + clock = null; + clock = new UuidClock(); + } + return clock.currentTime(); + } + +}
Index: UuidClock.java =================================================================== RCS file: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/uuid/UuidClock.java,v retrieving revision 1.1 diff -u -r1.1 UuidClock.java --- UuidClock.java 24 Dec 2003 08:59:45 -0000 1.1 +++ UuidClock.java 29 Dec 2003 23:28:22 -0000 @@ -1,224 +1,249 @@ -/* - * $Header: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/uuid/UuidClock.java,v 1.1 2003/12/24 08:59:45 psteitz Exp $ - * ==================================================================== - * - * The Apache Software License, Version 1.1 - * - * Copyright (c) 2001-2003 The Apache Software Foundation. All rights - * reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * 3. The end-user documentation included with the redistribution, if - * any, must include the following acknowledgement: - * "This product includes software developed by the - * Apache Software Foundation (http://www.apache.org/)." - * Alternately, this acknowledgement may appear in the software itself, - * if and wherever such third-party acknowledgements normally appear. - * - * 4. The names "The Jakarta Project", "Commons", and "Apache Software - * Foundation" must not be used to endorse or promote products derived - * from this software without prior written permission. For written - * permission, please contact [EMAIL PROTECTED] - * - * 5. Products derived from this software may not be called "Apache" - * nor may "Apache" appear in their names without prior written - * permission of the Apache Software Foundation. - * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR - * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF - * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND - * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT - * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * ==================================================================== - * - * This software consists of voluntary contributions made by many - * individuals on behalf of the Apache Software Foundation. For more - * information on the Apache Software Foundation, please see - * <http://www.apache.org/>. - * - */ - -package org.apache.commons.uid.uuid; - -/** - * UuidClock.java provides a timing mechanism for returning the current time in - * 100-nano second intervals since 00:00:00.00, 15 October 1582 - * - * As described below this is useful for generating Version 1 UUIDs - * - * For more information regarding the IETF Draft Uuid specification - * see http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-01.txt - * - * Selected segements of Draft pertaining to this class: - * - * ==================================================================== - * Timestamp - * The timestamp is a 60 bit value. For Uuid version 1, this is - * represented by Coordinated Universal Time (UTC) as a count of 100- - * nanosecond intervals since 00:00:00.00, 15 October 1582 (the date of - * Gregorian reform to the Christian calendar). - * - * Clock Adjustment - * UUIDs may be created at a rate greater than the system clock resolution. - * Therefore, the system must also maintain an adjustment value to be added to - * the lower-order bits of the time. Logically, each time the system clock - * ticks, the adjustment value is cleared. Every time a UUID is generated, - * the current adjustment value is read and incremented atomically, then added - * to the UTC time field of the UUID. - * - * Clock Overrun - * The 100 nanosecond granularity of time should prove sufficient even for - * bursts of UUID creation in the next generation of high-performance - * multiprocessors. If a system overruns the clock adjustment by requesting - * too many UUIDs within a single system clock tick, the UUID service may - * raise an exception, handled in a system or process-dependent manner - * either by: - * terminating the request - * reissuing the request until it succeeds - * stalling the UUID generator until the system clock catches up. - * - * If the processors overrun the UUID generation frequently, additional node - * identifiers and clocks may need to be added. - * ==================================================================== - * - * @version $Revision: 1.1 $ $Date: 2003/12/24 08:59:45 $ - * @author Tim Reilly - */ - -public class UuidClock extends Thread { - - /** Default life of the UuidClock thread in milliseconds */ - public static final long DEFAULT_THREAD_LIFE = 200; - - /** Offset from GregorianCalendar Change over to Jan 1 1970 00:00:00.00 */ - public static final long GREGORIAN_CHANGE_OFFSET = 12219292800000L; - - /** Maximum ticks per millisecond interval */ - public static final long TICKS_PER_MILLI = 10000L; - - /** Life time of the clock thread in milliseconds */ - private static long threadLife = DEFAULT_THREAD_LIFE; - - /** Singleton instance of the UuidClock */ - private static UuidClock clock = null; - - /** The counter for nanoseconds generated during this system interval(ms) */ - private int generatedThisMilli; - - /** The current time in milliseconds held in this clock thread. */ - private long currentTimeMillis; - - /** Time when the clock thread should die */ - private long expires = threadLife; - - /** - * Private constructor for clock implementation. Utilizes a single thread to - * increment the clock every milli seconds this should be more - * accurate than System.currentTimeMillis() as described in - * the javaworld article: - * http://www.javaworld.com/javaworld/javaqa/2003-01/01-qa-0110-timing.html - */ - - private UuidClock() { - setDaemon(true); - setPriority(Thread.MAX_PRIORITY); - currentTimeMillis = System.currentTimeMillis(); - start(); - } - - /** - * Returns the thread life in milliseconds. If the clock thread is not - * accessed within this time span the thread will die off. - * - * @return thread life time span in milliseconds - */ - public static long getThreadLife() { - return UuidClock.threadLife; - } - - /** - * @param threadLife milliseconds this thread should live for. Each - * call to getCurrentTime resets the expiration time value. - */ - public static void setThreadLife(long threadLife) { - UuidClock.threadLife = threadLife; - } - - /** - * Threads run method that increments the clock and resets the generated - * nano seconds counter. - */ - public void run() { - try { - while (--expires >= 0) { - Thread.sleep(1); - currentTimeMillis++; - generatedThisMilli = 1; - } - } catch (InterruptedException e) { - System.out.println("UuidClock thread interrupted"); - } - } - - /** - * Returns the internal time milliseconds for the UuidClock instance - * @return the clock threads current time in milliseconds - */ - private long getCurrentTimeMillis() { - return currentTimeMillis; - } - - /** - * Returns the current time as described in the clock resolution and - * timestamp sections of the uuid specification. - * - * @return the current time in 100-nano second intervals (simulated) - */ - private long currentTime() { - this.expires = threadLife; - // Stall until counter is reset to limit only 10000 intervals per - // millisecond interval - while (generatedThisMilli > TICKS_PER_MILLI) { - //wait for thread to reset - } - - long currentTime = - ((currentTimeMillis + GREGORIAN_CHANGE_OFFSET) * TICKS_PER_MILLI); - - return currentTime + (generatedThisMilli++); - } - - /** - * Static method returns the clocks current time in 100-nanosecond intervals - * since the Gregorian calander change. Calendar.GREGORIAN_OFFSET - * - * @return Coordinated Universal Time (UTC) as a count of 100- nanosecond - * intervals since 00:00:00.00, 15 October 1582 - */ - public static synchronized long getCurrentTime() { - if (clock == null || !clock.isAlive()) { - clock = null; - clock = new UuidClock(); - } - return clock.currentTime(); - } - -} +/* + * $Header: /home/cvspublic/jakarta-commons-sandbox/uid/src/java/org/apache/commons/uid/uuid/UuidClock.java,v 1.1 2003/12/24 08:59:45 psteitz Exp $ + * ==================================================================== + * + * The Apache Software License, Version 1.1 + * + * Copyright (c) 2001-2003 The Apache Software Foundation. All rights + * reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. The end-user documentation included with the redistribution, if + * any, must include the following acknowledgement: + * "This product includes software developed by the + * Apache Software Foundation (http://www.apache.org/)." + * Alternately, this acknowledgement may appear in the software itself, + * if and wherever such third-party acknowledgements normally appear. + * + * 4. The names "The Jakarta Project", "Commons", and "Apache Software + * Foundation" must not be used to endorse or promote products derived + * from this software without prior written permission. For written + * permission, please contact [EMAIL PROTECTED] + * + * 5. Products derived from this software may not be called "Apache" + * nor may "Apache" appear in their names without prior written + * permission of the Apache Software Foundation. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * ==================================================================== + * + * This software consists of voluntary contributions made by many + * individuals on behalf of the Apache Software Foundation. For more + * information on the Apache Software Foundation, please see + * <http://www.apache.org/>. + * + */ + +package org.apache.commons.uid.uuid; + +/** + * UuidClock.java provides a timing mechanism for returning the current time in + * 100-nano second intervals since 00:00:00.00, 15 October 1582 + * + * As described below this is useful for generating Version 1 UUIDs + * + * For more information regarding the IETF Draft Uuid specification + * see http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-01.txt + * + * Selected quotes from IETF document pertaining to this class: + * + * ==================================================================== + * -Timestamp- + * "The timestamp is a 60 bit value. For Uuid version 1, this is + * represented by Coordinated Universal Time (UTC) as a count of 100- + * nanosecond intervals since 00:00:00.00, 15 October 1582 (the date of + * Gregorian reform to the Christian calendar)." + * + * -Clock Adjustment- + * "UUIDs may be created at a rate greater than the system clock resolution. + * Therefore, the system must also maintain an adjustment value to be added to + * the lower-order bits of the time. Logically, each time the system clock + * ticks, the adjustment value is cleared. Every time a UUID is generated, + * the current adjustment value is read and incremented atomically, then added + * to the UTC time field of the UUID." + * + * -Clock Overrun- + * "The 100 nanosecond granularity of time should prove sufficient even for + * bursts of UUID creation in the next generation of high-performance + * multiprocessors. If a system overruns the clock adjustment by requesting + * too many UUIDs within a single system clock tick, the UUID service may + * raise an exception, handled in a system or process-dependent manner + * either by: + * terminating the request + * reissuing the request until it succeeds + * stalling the UUID generator until the system clock catches up. + * ... + * If the processors overrun the UUID generation frequently, additional node + * identifiers and clocks may need to be added." + * + * - The above quotations are protected under the following copyright notice - + * Copyright (C) The Internet Society (2003). All Rights Reserved. + * This document and translations of it may be copied and furnished to + * others, and derivative works that comment on or otherwise explain it + * or assist in its implementation may be prepared, copied, published + * and distributed, in whole or in part, without restriction of any + * kind, provided that the above copyright notice and this paragraph are + * included on all such copies and derivative works. However, this + * document itself may not be modified in any way, such as by removing + * the copyright notice or references to the Internet Society or other + * Internet organizations, except as needed for the purpose of + * developing Internet standards in which case the procedures for + * copyrights defined in the Internet Standards process must be + * followed, or as required to translate it into languages other than + * English. + * The limited permissions granted above are perpetual and will not be + * revoked by the Internet Society or its successors or assignees. + * This document and the information contained herein is provided on an + * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + * + * ==================================================================== + * + * @version $Revision: 1.1 $ $Date: 2003/12/24 08:59:45 $ + * + */ + +public class UuidClock extends Thread { + + /** Default life of the UuidClock thread in milliseconds */ + public static final long DEFAULT_THREAD_LIFE = 200; + + /** Offset from GregorianCalendar Change over to Jan 1 1970 00:00:00.00 */ + public static final long GREGORIAN_CHANGE_OFFSET = 12219292800000L; + + /** Maximum ticks per millisecond interval */ + public static final long TICKS_PER_MILLI = 10000L; + + /** Life time of the clock thread in milliseconds */ + private static long threadLife = DEFAULT_THREAD_LIFE; + + /** Singleton instance of the UuidClock */ + private static UuidClock clock = null; + + /** The counter for nanoseconds generated during this system interval(ms) */ + private int generatedThisMilli; + + /** The current time in milliseconds held in this clock thread. */ + private long currentTimeMillis; + + /** Time when the clock thread should die */ + private long expires = threadLife; + + /** + * Private constructor for clock implementation. Utilizes a single thread to + * increment the clock every milli seconds this should be more + * accurate than System.currentTimeMillis() as described in + * the javaworld article: + * http://www.javaworld.com/javaworld/javaqa/2003-01/01-qa-0110-timing.html + */ + + private UuidClock() { + setDaemon(true); + setPriority(Thread.MAX_PRIORITY); + currentTimeMillis = System.currentTimeMillis(); + start(); + } + + /** + * Returns the thread life in milliseconds. If the clock thread is not + * accessed within this time span the thread will die off. + * + * @return thread life time span in milliseconds + */ + public static long getThreadLife() { + return UuidClock.threadLife; + } + + /** + * @param threadLife milliseconds this thread should live for. Each + * call to getCurrentTime resets the expiration time value. + */ + public static void setThreadLife(long threadLife) { + UuidClock.threadLife = threadLife; + } + + /** + * Threads run method that increments the clock and resets the generated + * nano seconds counter. + */ + public void run() { + try { + while (--expires >= 0) { + Thread.sleep(1); + currentTimeMillis++; + generatedThisMilli = 1; + } + } catch (InterruptedException e) { + System.out.println("UuidClock thread interrupted"); + } + } + + /** + * Returns the internal time milliseconds for the UuidClock instance + * @return the clock threads current time in milliseconds + */ + private long getCurrentTimeMillis() { + return currentTimeMillis; + } + + /** + * Returns the current time as described in the clock resolution and + * timestamp sections of the uuid specification. + * + * @return the current time in 100-nano second intervals (simulated) + */ + private long currentTime() { + this.expires = threadLife; + // Stall until counter is reset to limit only 10000 intervals per + // millisecond interval + while (generatedThisMilli > TICKS_PER_MILLI) { + //wait for thread to reset + } + + long currentTime = + ((currentTimeMillis + GREGORIAN_CHANGE_OFFSET) * TICKS_PER_MILLI); + + return currentTime + (generatedThisMilli++); + } + + /** + * Static method returns the clocks current time in 100-nanosecond intervals + * since the Gregorian calander change. Calendar.GREGORIAN_OFFSET + * + * @return Coordinated Universal Time (UTC) as a count of 100- nanosecond + * intervals since 00:00:00.00, 15 October 1582 + */ + public static synchronized long getCurrentTime() { + if (clock == null || !clock.isAlive()) { + clock = null; + clock = new UuidClock(); + } + return clock.currentTime(); + } + +}
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