Develop Reference

How to LocalDateTime but use server time or internet time? [duplicate]

I would like to get the GMT [ Greenwich Mean Time ], and also I don't want to rely on my system date time for that. Basically, I want to use time sync server like in.pool.ntp.org [ India ] for GMT calculation, or may be I am going in wrong direction!
How to do this in java ?
Is there any java library to get time from Time server?

sp0d is not quite right:
timeInfo.getReturnTime(); // Returns time at which time message packet was received by local machine
So it just returns current system time, not the received one. See TimeInfo man page.
You should use
timeInfo.getMessage().getTransmitTimeStamp().getTime();
instead.
So the code block will be:
String TIME_SERVER = "time-a.nist.gov";
NTPUDPClient timeClient = new NTPUDPClient();
InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);
TimeInfo timeInfo = timeClient.getTime(inetAddress);
long returnTime = timeInfo.getMessage().getTransmitTimeStamp().getTime();
Date time = new Date(returnTime);

Here is a code i found somewhere else.. and i am using it. Uses apache commons library.
List of time servers: NIST Internet Time Service
import java.net.InetAddress;
import java.util.Date;
import org.apache.commons.net.ntp.NTPUDPClient;
import org.apache.commons.net.ntp.TimeInfo;
public class TimeLookup {
public static void main() throws Exception {
String TIME_SERVER = "time-a.nist.gov";
NTPUDPClient timeClient = new NTPUDPClient();
InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);
TimeInfo timeInfo = timeClient.getTime(inetAddress);
long returnTime = timeInfo.getReturnTime();
Date time = new Date(returnTime);
System.out.println("Time from " + TIME_SERVER + ": " + time);
}
}
Returns the output
Time from time-d.nist.gov: Sun Nov 25 06:04:34 IST 2012

I know this is an old question but I notice that all the answers are not correct or are complicated.
A nice and simple way to implement it is using Apache Commons Net library. This library will provide a NTPUDPClient class to manage connectionless NTP requests. This class will return a TimeInfo instance. This object should run the compute method to calculate the offset between your system's time and the NTP server's time. Lets try to implement it here
Add the Apache Commons Net library to your project.
<dependency>
<groupId>commons-net</groupId>
<artifactId>commons-net</artifactId>
<version>3.6</version>
</dependency>
Create a new instance of the NTPUDPClient class.
Setup the default timeout
Get the InetAddress of the NTP Server.
Call the NTPUDPClient.getTime() method to retrieve a TimeInfo instance with the time information from the specified server.
Call the computeDetails() method to compute and validate details of the NTP message packet.
Finally, get a NTP timestamp object based on a Java time by using this code TimeStamp.getNtpTime(currentTime + offset).getTime().
Here we have a basic implementation:
import java.net.InetAddress;
import java.util.Date;
import org.apache.commons.net.ntp.NTPUDPClient;
import org.apache.commons.net.ntp.TimeInfo;
public class NTPClient {
private static final String SERVER_NAME = "pool.ntp.org";
private volatile TimeInfo timeInfo;
private volatile Long offset;
public static void main() throws Exception {
NTPUDPClient client = new NTPUDPClient();
// We want to timeout if a response takes longer than 10 seconds
client.setDefaultTimeout(10_000);
InetAddress inetAddress = InetAddress.getByName(SERVER_NAME);
TimeInfo timeInfo = client.getTime(inetAddress);
timeInfo.computeDetails();
if (timeInfo.getOffset() != null) {
this.timeInfo = timeInfo;
this.offset = timeInfo.getOffset();
}
// This system NTP time
TimeStamp systemNtpTime = TimeStamp.getCurrentTime();
System.out.println("System time:\t" + systemNtpTime + " " + systemNtpTime.toDateString());
// Calculate the remote server NTP time
long currentTime = System.currentTimeMillis();
TimeStamp atomicNtpTime = TimeStamp.getNtpTime(currentTime + offset).getTime()
System.out.println("Atomic time:\t" + atomicNtpTime + " " + atomicNtpTime.toDateString());
}
public boolean isComputed()
{
return timeInfo != null && offset != null;
}
}
You will get something like that:
System time: dfaa2c15.2083126e Thu, Nov 29 2018 18:12:53.127
Atomic time: dfaa2c15.210624dd Thu, Nov 29 2018 18:12:53.129

This link demonstrates a java class called NtpMessage.java that you can paste into your program which will fetch the current time from an NTP server.
At the following link, Find the "Attachment" section near the bottom and download NtpMessage.java and SntpClient.java and paste it into your java application. It will do all the work and fetch you the time.
http://support.ntp.org/bin/view/Support/JavaSntpClient
Copy and paste of the code if it goes down:
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* This class represents a NTP message, as specified in RFC 2030. The message
* format is compatible with all versions of NTP and SNTP.
*
* This class does not support the optional authentication protocol, and
* ignores the key ID and message digest fields.
*
* For convenience, this class exposes message values as native Java types, not
* the NTP-specified data formats. For example, timestamps are
* stored as doubles (as opposed to the NTP unsigned 64-bit fixed point
* format).
*
* However, the contructor NtpMessage(byte[]) and the method toByteArray()
* allow the import and export of the raw NTP message format.
*
*
* Usage example
*
* // Send message
* DatagramSocket socket = new DatagramSocket();
* InetAddress address = InetAddress.getByName("ntp.cais.rnp.br");
* byte[] buf = new NtpMessage().toByteArray();
* DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 123);
* socket.send(packet);
*
* // Get response
* socket.receive(packet);
* System.out.println(msg.toString());
*
*
* This code is copyright (c) Adam Buckley 2004
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version. A HTML version of the GNU General Public License can be
* seen at http://www.gnu.org/licenses/gpl.html
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
*
* Comments for member variables are taken from RFC2030 by David Mills,
* University of Delaware.
*
* Number format conversion code in NtpMessage(byte[] array) and toByteArray()
* inspired by http://www.pps.jussieu.fr/~jch/enseignement/reseaux/
* NTPMessage.java which is copyright (c) 2003 by Juliusz Chroboczek
*
* #author Adam Buckley
*/
public class NtpMessage
{
/**
* This is a two-bit code warning of an impending leap second to be
* inserted/deleted in the last minute of the current day. It's values
* may be as follows:
*
* Value Meaning
* ----- -------
* 0 no warning
* 1 last minute has 61 seconds
* 2 last minute has 59 seconds)
* 3 alarm condition (clock not synchronized)
*/
public byte leapIndicator = 0;
/**
* This value indicates the NTP/SNTP version number. The version number
* is 3 for Version 3 (IPv4 only) and 4 for Version 4 (IPv4, IPv6 and OSI).
* If necessary to distinguish between IPv4, IPv6 and OSI, the
* encapsulating context must be inspected.
*/
public byte version = 3;
/**
* This value indicates the mode, with values defined as follows:
*
* Mode Meaning
* ---- -------
* 0 reserved
* 1 symmetric active
* 2 symmetric passive
* 3 client
* 4 server
* 5 broadcast
* 6 reserved for NTP control message
* 7 reserved for private use
*
* In unicast and anycast modes, the client sets this field to 3 (client)
* in the request and the server sets it to 4 (server) in the reply. In
* multicast mode, the server sets this field to 5 (broadcast).
*/
public byte mode = 0;
/**
* This value indicates the stratum level of the local clock, with values
* defined as follows:
*
* Stratum Meaning
* ----------------------------------------------
* 0 unspecified or unavailable
* 1 primary reference (e.g., radio clock)
* 2-15 secondary reference (via NTP or SNTP)
* 16-255 reserved
*/
public short stratum = 0;
/**
* This value indicates the maximum interval between successive messages,
* in seconds to the nearest power of two. The values that can appear in
* this field presently range from 4 (16 s) to 14 (16284 s); however, most
* applications use only the sub-range 6 (64 s) to 10 (1024 s).
*/
public byte pollInterval = 0;
/**
* This value indicates the precision of the local clock, in seconds to
* the nearest power of two. The values that normally appear in this field
* range from -6 for mains-frequency clocks to -20 for microsecond clocks
* found in some workstations.
*/
public byte precision = 0;
/**
* This value indicates the total roundtrip delay to the primary reference
* source, in seconds. Note that this variable can take on both positive
* and negative values, depending on the relative time and frequency
* offsets. The values that normally appear in this field range from
* negative values of a few milliseconds to positive values of several
* hundred milliseconds.
*/
public double rootDelay = 0;
/**
* This value indicates the nominal error relative to the primary reference
* source, in seconds. The values that normally appear in this field
* range from 0 to several hundred milliseconds.
*/
public double rootDispersion = 0;
/**
* This is a 4-byte array identifying the particular reference source.
* In the case of NTP Version 3 or Version 4 stratum-0 (unspecified) or
* stratum-1 (primary) servers, this is a four-character ASCII string, left
* justified and zero padded to 32 bits. In NTP Version 3 secondary
* servers, this is the 32-bit IPv4 address of the reference source. In NTP
* Version 4 secondary servers, this is the low order 32 bits of the latest
* transmit timestamp of the reference source. NTP primary (stratum 1)
* servers should set this field to a code identifying the external
* reference source according to the following list. If the external
* reference is one of those listed, the associated code should be used.
* Codes for sources not listed can be contrived as appropriate.
*
* Code External Reference Source
* ---- -------------------------
* LOCL uncalibrated local clock used as a primary reference for
* a subnet without external means of synchronization
* PPS atomic clock or other pulse-per-second source
* individually calibrated to national standards
* ACTS NIST dialup modem service
* USNO USNO modem service
* PTB PTB (Germany) modem service
* TDF Allouis (France) Radio 164 kHz
* DCF Mainflingen (Germany) Radio 77.5 kHz
* MSF Rugby (UK) Radio 60 kHz
* WWV Ft. Collins (US) Radio 2.5, 5, 10, 15, 20 MHz
* WWVB Boulder (US) Radio 60 kHz
* WWVH Kaui Hawaii (US) Radio 2.5, 5, 10, 15 MHz
* CHU Ottawa (Canada) Radio 3330, 7335, 14670 kHz
* LORC LORAN-C radionavigation system
* OMEG OMEGA radionavigation system
* GPS Global Positioning Service
* GOES Geostationary Orbit Environment Satellite
*/
public byte[] referenceIdentifier = {0, 0, 0, 0};
/**
* This is the time at which the local clock was last set or corrected, in
* seconds since 00:00 1-Jan-1900.
*/
public double referenceTimestamp = 0;
/**
* This is the time at which the request departed the client for the
* server, in seconds since 00:00 1-Jan-1900.
*/
public double originateTimestamp = 0;
/**
* This is the time at which the request arrived at the server, in seconds
* since 00:00 1-Jan-1900.
*/
public double receiveTimestamp = 0;
/**
* This is the time at which the reply departed the server for the client,
* in seconds since 00:00 1-Jan-1900.
*/
public double transmitTimestamp = 0;
/**
* Constructs a new NtpMessage from an array of bytes.
*/
public NtpMessage(byte[] array)
{
// See the packet format diagram in RFC 2030 for details
leapIndicator = (byte) ((array[0] >> 6) & 0x3);
version = (byte) ((array[0] >> 3) & 0x7);
mode = (byte) (array[0] & 0x7);
stratum = unsignedByteToShort(array[1]);
pollInterval = array[2];
precision = array[3];
rootDelay = (array[4] * 256.0) +
unsignedByteToShort(array[5]) +
(unsignedByteToShort(array[6]) / 256.0) +
(unsignedByteToShort(array[7]) / 65536.0);
rootDispersion = (unsignedByteToShort(array[8]) * 256.0) +
unsignedByteToShort(array[9]) +
(unsignedByteToShort(array[10]) / 256.0) +
(unsignedByteToShort(array[11]) / 65536.0);
referenceIdentifier[0] = array[12];
referenceIdentifier[1] = array[13];
referenceIdentifier[2] = array[14];
referenceIdentifier[3] = array[15];
referenceTimestamp = decodeTimestamp(array, 16);
originateTimestamp = decodeTimestamp(array, 24);
receiveTimestamp = decodeTimestamp(array, 32);
transmitTimestamp = decodeTimestamp(array, 40);
}
/**
* Constructs a new NtpMessage in client -> server mode, and sets the
* transmit timestamp to the current time.
*/
public NtpMessage()
{
// Note that all the other member variables are already set with
// appropriate default values.
this.mode = 3;
this.transmitTimestamp = (System.currentTimeMillis()/1000.0) + 2208988800.0;
}
/**
* This method constructs the data bytes of a raw NTP packet.
*/
public byte[] toByteArray()
{
// All bytes are automatically set to 0
byte[] p = new byte[48];
p[0] = (byte) (leapIndicator << 6 | version << 3 | mode);
p[1] = (byte) stratum;
p[2] = (byte) pollInterval;
p[3] = (byte) precision;
// root delay is a signed 16.16-bit FP, in Java an int is 32-bits
int l = (int) (rootDelay * 65536.0);
p[4] = (byte) ((l >> 24) & 0xFF);
p[5] = (byte) ((l >> 16) & 0xFF);
p[6] = (byte) ((l >> 8) & 0xFF);
p[7] = (byte) (l & 0xFF);
// root dispersion is an unsigned 16.16-bit FP, in Java there are no
// unsigned primitive types, so we use a long which is 64-bits
long ul = (long) (rootDispersion * 65536.0);
p[8] = (byte) ((ul >> 24) & 0xFF);
p[9] = (byte) ((ul >> 16) & 0xFF);
p[10] = (byte) ((ul >> 8) & 0xFF);
p[11] = (byte) (ul & 0xFF);
p[12] = referenceIdentifier[0];
p[13] = referenceIdentifier[1];
p[14] = referenceIdentifier[2];
p[15] = referenceIdentifier[3];
encodeTimestamp(p, 16, referenceTimestamp);
encodeTimestamp(p, 24, originateTimestamp);
encodeTimestamp(p, 32, receiveTimestamp);
encodeTimestamp(p, 40, transmitTimestamp);
return p;
}
/**
* Returns a string representation of a NtpMessage
*/
public String toString()
{
String precisionStr =
new DecimalFormat("0.#E0").format(Math.pow(2, precision));
return "Leap indicator: " + leapIndicator + "\n" +
"Version: " + version + "\n" +
"Mode: " + mode + "\n" +
"Stratum: " + stratum + "\n" +
"Poll: " + pollInterval + "\n" +
"Precision: " + precision + " (" + precisionStr + " seconds)\n" +
"Root delay: " + new DecimalFormat("0.00").format(rootDelay*1000) + " ms\n" +
"Root dispersion: " + new DecimalFormat("0.00").format(rootDispersion*1000) + " ms\n" +
"Reference identifier: " + referenceIdentifierToString(referenceIdentifier, stratum, version) + "\n" +
"Reference timestamp: " + timestampToString(referenceTimestamp) + "\n" +
"Originate timestamp: " + timestampToString(originateTimestamp) + "\n" +
"Receive timestamp: " + timestampToString(receiveTimestamp) + "\n" +
"Transmit timestamp: " + timestampToString(transmitTimestamp);
}
/**
* Converts an unsigned byte to a short. By default, Java assumes that
* a byte is signed.
*/
public static short unsignedByteToShort(byte b)
{
if((b & 0x80)==0x80) return (short) (128 + (b & 0x7f));
else return (short) b;
}
/**
* Will read 8 bytes of a message beginning at <code>pointer</code>
* and return it as a double, according to the NTP 64-bit timestamp
* format.
*/
public static double decodeTimestamp(byte[] array, int pointer)
{
double r = 0.0;
for(int i=0; i<8; i++)
{
r += unsignedByteToShort(array[pointer+i]) * Math.pow(2, (3-i)*8);
}
return r;
}
/**
* Encodes a timestamp in the specified position in the message
*/
public static void encodeTimestamp(byte[] array, int pointer, double timestamp)
{
// Converts a double into a 64-bit fixed point
for(int i=0; i<8; i++)
{
// 2^24, 2^16, 2^8, .. 2^-32
double base = Math.pow(2, (3-i)*8);
// Capture byte value
array[pointer+i] = (byte) (timestamp / base);
// Subtract captured value from remaining total
timestamp = timestamp - (double) (unsignedByteToShort(array[pointer+i]) * base);
}
// From RFC 2030: It is advisable to fill the non-significant
// low order bits of the timestamp with a random, unbiased
// bitstring, both to avoid systematic roundoff errors and as
// a means of loop detection and replay detection.
array[7] = (byte) (Math.random()*255.0);
}
/**
* Returns a timestamp (number of seconds since 00:00 1-Jan-1900) as a
* formatted date/time string.
*/
public static String timestampToString(double timestamp)
{
if(timestamp==0) return "0";
// timestamp is relative to 1900, utc is used by Java and is relative
// to 1970
double utc = timestamp - (2208988800.0);
// milliseconds
long ms = (long) (utc * 1000.0);
// date/time
String date = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss").format(new Date(ms));
// fraction
double fraction = timestamp - ((long) timestamp);
String fractionSting = new DecimalFormat(".000000").format(fraction);
return date + fractionSting;
}
/**
* Returns a string representation of a reference identifier according
* to the rules set out in RFC 2030.
*/
public static String referenceIdentifierToString(byte[] ref, short stratum, byte version)
{
// From the RFC 2030:
// In the case of NTP Version 3 or Version 4 stratum-0 (unspecified)
// or stratum-1 (primary) servers, this is a four-character ASCII
// string, left justified and zero padded to 32 bits.
if(stratum==0 || stratum==1)
{
return new String(ref);
}
// In NTP Version 3 secondary servers, this is the 32-bit IPv4
// address of the reference source.
else if(version==3)
{
return unsignedByteToShort(ref[0]) + "." +
unsignedByteToShort(ref[1]) + "." +
unsignedByteToShort(ref[2]) + "." +
unsignedByteToShort(ref[3]);
}
// In NTP Version 4 secondary servers, this is the low order 32 bits
// of the latest transmit timestamp of the reference source.
else if(version==4)
{
return "" + ((unsignedByteToShort(ref[0]) / 256.0) +
(unsignedByteToShort(ref[1]) / 65536.0) +
(unsignedByteToShort(ref[2]) / 16777216.0) +
(unsignedByteToShort(ref[3]) / 4294967296.0));
}
return "";
}
}

The server time-a.nist.gov does not list the time port; you have to use correct server ntp.xs4all.nl for getting date and time from internet:
String TIME_SERVER = "ntp.xs4all.nl";
//... some other code

How to change execution speed? [duplicate]

If you had read my other question, you'll know I've spent this weekend putting together a 6502 CPU emulator as a programming exercise.
The CPU emulator is mostly complete, and seems to be fairly accurate from my limited testing, however it is running incredibly fast, and I want to throttle it down to the actual clock speed of the machine.
My current test loop is this:
// Just loop infinitely.
while (1 == 1)
{
CPU.ClockCyclesBeforeNext--;
if (CPU.ClockCyclesBeforeNext <= 0)
{
// Find out how many clock cycles this instruction will take
CPU.ClockCyclesBeforeNext = CPU.OpcodeMapper.Map[CPU.Memory[CPU.PC]].CpuCycles;
// Run the instruction
CPU.ExecuteInstruction(CPU.Memory[CPU.PC]);
// Debugging Info
CPU.DumpDebug();
Console.WriteLine(CPU.OpcodeMapper.Map[CPU.Memory[CPU.PC]].ArgumentLength);
// Move to next instruction
CPU.PC += 1 + CPU.OpcodeMapper.Map[CPU.Memory[CPU.PC]].ArgumentLength;
}
}
As you can tell, each opcode takes a specific amount of time to complete, so I do not run the next instruction until I count down the CPU Cycle clock. This provides proper timing between opcodes, its just that the entire thing runs way to fast.
The targeted CPU speed is 1.79mhz, however I'd like whatever solution to the clock issue to keep the speed at 1.79mhz even as I add complexity, so I don't have to adjust it up.
Any ideas?

I wrote a Z80 emulator many years ago, and to do cycle accurate execution, I divided the clock rate into a number of small blocks and had the core execute that many clock cycles. In my case, I tied it to the frame rate of the game system I was emulating. Each opcode knew how many cycles it took to execute and the core would keep running opcodes until the specified number of cycles had been executed. I had an outer run loop that would run the cpu core, and run other parts of the emulated system and then sleep until the start time of the next iteration.
EDIT: Adding example of run loop.
int execute_run_loop( int cycles )
{
int n = 0;
while( n < cycles )
{
/* Returns number of cycles executed */
n += execute_next_opcode();
}
return n;
}
Hope this helps.

Take a look at the original quicktime documentation for inspiration.
It was written a long time ago, when displaying video meant just swapping still frames at high enough speed, but the Apple guys decided they needed a full time-management framework. The design at first looks overengineered, but it let them deal with widely different speed requirements and keep them tightly synchronized.
you're fortunate that 6502 has deterministic time behaviour, the exact time each instruction takes is well documented; but it's not constant. some instructions take 2 cycles, other 3. Just like frames in QuickTime, a video doesn't have a 'frames per second' parameter, each frame tells how long it wants to be in screen.
Since modern CPU's are so non-deterministic, and multitasking OS's can even freeze for a few miliseconds (virtual memory!), you should keep a tab if you're behind schedule, or if you can take a few microseconds nap.

As jfk says, the most common way to do this is tie the cpu speed to the vertical refresh of the (emulated) video output.
Pick a number of cycles to run per video frame. This will often be machine-specific but you can calculate it by something like :
cycles = clock speed in Hz / required frames-per-second
Then you also get to do a sleep until the video update is hit, at which point you start the next n cycles of CPU emulation.
If you're emulating something in particular then you just need to look up the fps rate and processor speed to get this approximately right.
EDIT: If you don't have any external timing requirements then it is normal for an emulator to just run as fast as it possibly can. Sometimes this is a desired effect and sometimes not :)

I would use the clock cycles to calculate time and them sleep the difference in time. Of course, to do this, you need a high-resolution clock. They way you are doing it is going to spike the CPU in spinning loops.

Yes, as said before most of the time you don't need a CPU emulator to emulate instructions at the same speed of the real thing. What user perceive is the output of the computation (i.e. audio and video outputs) so you only need to be in sync with such outputs which doesn't mean you must have necessarily an exact CPU emulation speed.
In other words, if the frame rate of the video input is, let's say, 50Hz, then let the CPU emulator run as fast as it can to draw the screen but be sure to output the screen frames at the correct rate (50Hz). From an external point of view your emulator is emulating at the correct speed.
Trying to be cycle exact even in the execution time is a non-sense on a multi-tasking OS like Windows or Linux because the emulator instruction time (tipically 1uS for vintage 80s CPUs) and the scheduling time slot of the modern OS are comparable.
Trying to output something at a 50Hz rate is a much simpler task you can do very good on any modern machine

Another option is available if audio emulation is implemented, and if audio output is tied to the system/CPU clock. In particular I know that this is the case with the 8-bit Apple ][ computers.
Usually sound is generated in buffers of a fixed size (which is a fixed time), so operation (generation of data etc) of these buffers can be tied to CPU throughput via synchronization primitives.

I am in the process of making something a little more general use case based, such as the ability to convert time to an estimated amount of instructions and vice versa.
The project homepage is # http://net7mma.codeplex.com
The code starts like this: (I think)
#region Copyright
/*
This file came from Managed Media Aggregation, You can always find the latest version # https://net7mma.codeplex.com/
Julius.Friedman#gmail.com / (SR. Software Engineer ASTI Transportation Inc. http://www.asti-trans.com)
Permission is hereby granted, free of charge,
* to any person obtaining a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction,
* including without limitation the rights to :
* use,
* copy,
* modify,
* merge,
* publish,
* distribute,
* sublicense,
* and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*
*
* JuliusFriedman#gmail.com should be contacted for further details.
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
*
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE,
* ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* v//
*/
#endregion
namespace Media.Concepts.Classes
{
//Windows.Media.Clock has a fairly complex but complete API
/// <summary>
/// Provides a clock with a given offset and calendar.
/// </summary>
public class Clock : Media.Common.BaseDisposable
{
static bool GC = false;
#region Fields
/// <summary>
/// Indicates when the clock was created
/// </summary>
public readonly System.DateTimeOffset Created;
/// <summary>
/// The calendar system of the clock
/// </summary>
public readonly System.Globalization.Calendar Calendar;
/// <summary>
/// The amount of ticks which occur per update of the <see cref="System.Environment.TickCount"/> member.
/// </summary>
public readonly long TicksPerUpdate;
/// <summary>
/// The amount of instructions which occured when synchronizing with the system clock.
/// </summary>
public readonly long InstructionsPerClockUpdate;
#endregion
#region Properties
/// <summary>
/// The TimeZone offset of the clock from UTC
/// </summary>
public System.TimeSpan Offset { get { return Created.Offset; } }
/// <summary>
/// The average amount of operations per tick.
/// </summary>
public long AverageOperationsPerTick { get { return InstructionsPerClockUpdate / TicksPerUpdate; } }
/// <summary>
/// The <see cref="System.TimeSpan"/> which represents <see cref="TicksPerUpdate"/> as an amount of time.
/// </summary>
public System.TimeSpan SystemClockResolution { get { return System.TimeSpan.FromTicks(TicksPerUpdate); } }
/// <summary>
/// Return the current system time in the TimeZone offset of this clock
/// </summary>
public System.DateTimeOffset Now { get { return System.DateTimeOffset.Now.ToOffset(Offset).Add(new System.TimeSpan((long)(AverageOperationsPerTick / System.TimeSpan.TicksPerMillisecond))); } }
/// <summary>
/// Return the current system time in the TimeZone offset of this clock converter to UniversalTime.
/// </summary>
public System.DateTimeOffset UtcNow { get { return Now.ToUniversalTime(); } }
//public bool IsUtc { get { return Offset == System.TimeSpan.Zero; } }
//public bool IsDaylightSavingTime { get { return Created.LocalDateTime.IsDaylightSavingTime(); } }
#endregion
#region Constructor
/// <summary>
/// Creates a clock using the system's current timezone and calendar.
/// The system clock is profiled to determine it's accuracy
/// <see cref="System.DateTimeOffset.Now.Offset"/>
/// <see cref="System.Globalization.CultureInfo.CurrentCulture.Calendar"/>
/// </summary>
public Clock(bool shouldDispose = true)
: this(System.DateTimeOffset.Now.Offset, System.Globalization.CultureInfo.CurrentCulture.Calendar, shouldDispose)
{
try { if (false == GC && System.Runtime.GCSettings.LatencyMode != System.Runtime.GCLatencyMode.NoGCRegion) GC = System.GC.TryStartNoGCRegion(0); }
catch { }
finally
{
System.Threading.Thread.BeginCriticalRegion();
//Sample the TickCount
long ticksStart = System.Environment.TickCount,
ticksEnd;
//Continually sample the TickCount. while the value has not changed increment InstructionsPerClockUpdate
while ((ticksEnd = System.Environment.TickCount) == ticksStart) ++InstructionsPerClockUpdate; //+= 4; Read,Assign,Compare,Increment
//How many ticks occur per update of TickCount
TicksPerUpdate = ticksEnd - ticksStart;
System.Threading.Thread.EndCriticalRegion();
}
}
/// <summary>
/// Constructs a new clock using the given TimeZone offset and Calendar system
/// </summary>
/// <param name="timeZoneOffset"></param>
/// <param name="calendar"></param>
/// <param name="shouldDispose">Indicates if the instace should be diposed when Dispose is called.</param>
public Clock(System.TimeSpan timeZoneOffset, System.Globalization.Calendar calendar, bool shouldDispose = true)
{
//Allow disposal
ShouldDispose = shouldDispose;
Calendar = System.Globalization.CultureInfo.CurrentCulture.Calendar;
Created = new System.DateTimeOffset(System.DateTime.Now, timeZoneOffset);
}
#endregion
#region Overrides
public override void Dispose()
{
if (false == ShouldDispose) return;
base.Dispose();
try
{
if (System.Runtime.GCSettings.LatencyMode == System.Runtime.GCLatencyMode.NoGCRegion)
{
System.GC.EndNoGCRegion();
GC = false;
}
}
catch { }
}
#endregion
//Methods or statics for OperationCountToTimeSpan? (Estimate)
public void NanoSleep(int nanos)
{
Clock.NanoSleep((long)nanos);
}
public static void NanoSleep(long nanos)
{
System.Threading.Thread.BeginCriticalRegion();
NanoSleep(ref nanos);
System.Threading.Thread.EndCriticalRegion();
}
static void NanoSleep(ref long nanos)
{
try
{
unchecked
{
while (Common.Binary.Clamp(--nanos, 0, 1) >= 2)
{
/* if(--nanos % 2 == 0) */
NanoSleep(long.MinValue); //nanos -= 1 + (ops / (ulong)AverageOperationsPerTick);// *10;
}
}
}
catch
{
return;
}
}
}
}
Once you have some type of layman clock implementation you advance to something like a Timer
/// <summary>
/// Provides a Timer implementation which can be used across all platforms and does not rely on the existing Timer implementation.
/// </summary>
public class Timer : Common.BaseDisposable
{
readonly System.Threading.Thread m_Counter; // m_Consumer, m_Producer
internal System.TimeSpan m_Frequency;
internal ulong m_Ops = 0, m_Ticks = 0;
bool m_Enabled;
internal System.DateTimeOffset m_Started;
public delegate void TickEvent(ref long ticks);
public event TickEvent Tick;
public bool Enabled { get { return m_Enabled; } set { m_Enabled = value; } }
public System.TimeSpan Frequency { get { return m_Frequency; } }
internal ulong m_Bias;
//
//Could just use a single int, 32 bits is more than enough.
//uint m_Flags;
//
readonly internal Clock m_Clock = new Clock();
readonly internal System.Collections.Generic.Queue<long> Producer;
void Count()
{
System.Threading.Thread Event = new System.Threading.Thread(new System.Threading.ThreadStart(() =>
{
System.Threading.Thread.BeginCriticalRegion();
long sample;
AfterSample:
try
{
Top:
System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.Highest;
while (m_Enabled && Producer.Count >= 1)
{
sample = Producer.Dequeue();
Tick(ref sample);
}
System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.Lowest;
if (false == m_Enabled) return;
while (m_Enabled && Producer.Count == 0) if(m_Counter.IsAlive) m_Counter.Join(0); //++m_Ops;
goto Top;
}
catch { if (false == m_Enabled) return; goto AfterSample; }
finally { System.Threading.Thread.EndCriticalRegion(); }
}))
{
IsBackground = false,
Priority = System.Threading.ThreadPriority.AboveNormal
};
Event.TrySetApartmentState(System.Threading.ApartmentState.MTA);
Event.Start();
Approximate:
ulong approximate = (ulong)Common.Binary.Clamp((m_Clock.AverageOperationsPerTick / (Frequency.Ticks + 1)), 1, ulong.MaxValue);
try
{
m_Started = m_Clock.Now;
System.Threading.Thread.BeginCriticalRegion();
unchecked
{
Start:
if (IsDisposed) return;
switch (++m_Ops)
{
default:
{
if (m_Bias + ++m_Ops >= approximate)
{
System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.Highest;
Producer.Enqueue((long)m_Ticks++);
ulong x = ++m_Ops / approximate;
while (1 > --x /*&& Producer.Count <= m_Frequency.Ticks*/) Producer.Enqueue((long)++m_Ticks);
m_Ops = (++m_Ops * m_Ticks) - (m_Bias = ++m_Ops / approximate);
System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.Lowest;
}
if(Event != null) Event.Join(m_Frequency);
goto Start;
}
}
}
}
catch (System.Threading.ThreadAbortException) { if (m_Enabled) goto Approximate; System.Threading.Thread.ResetAbort(); }
catch (System.OutOfMemoryException) { if ((ulong)Producer.Count > approximate) Producer.Clear(); if (m_Enabled) goto Approximate; }
catch { if (m_Enabled) goto Approximate; }
finally
{
Event = null;
System.Threading.Thread.EndCriticalRegion();
}
}
public Timer(System.TimeSpan frequency)
{
Producer = new System.Collections.Generic.Queue<long>((int)(m_Frequency = frequency).Ticks * 10);
m_Counter = new System.Threading.Thread(new System.Threading.ThreadStart(Count))
{
IsBackground = false,
Priority = System.Threading.ThreadPriority.AboveNormal
};
m_Counter.TrySetApartmentState(System.Threading.ApartmentState.MTA);
Tick = delegate { m_Ops += 1 + m_Bias; };
}
public void Start()
{
if (m_Enabled) return;
m_Enabled = true;
m_Counter.Start();
var p = System.Threading.Thread.CurrentThread.Priority;
System.Threading.Thread.CurrentThread.Priority = System.Threading.ThreadPriority.Lowest;
while (m_Ops == 0) m_Counter.Join(0); //m_Clock.NanoSleep(0);
System.Threading.Thread.CurrentThread.Priority = p;
}
public void Stop()
{
m_Enabled = false;
}
void Change(System.TimeSpan interval, System.TimeSpan dueTime)
{
m_Enabled = false;
m_Frequency = interval;
m_Enabled = true;
}
delegate void ElapsedEvent(object sender, object args);
public override void Dispose()
{
if (IsDisposed) return;
base.Dispose();
Stop();
try { m_Counter.Abort(m_Frequency); }
catch (System.Threading.ThreadAbortException) { System.Threading.Thread.ResetAbort(); }
catch { }
Tick = null;
//Producer.Clear();
}
}
Then you can really replicate some logic using something like
/// <summary>
/// Provides a completely managed implementation of <see cref="System.Diagnostics.Stopwatch"/> which expresses time in the same units as <see cref="System.TimeSpan"/>.
/// </summary>
public class Stopwatch : Common.BaseDisposable
{
internal Timer Timer;
long Units;
public bool Enabled { get { return Timer != null && Timer.Enabled; } }
public double ElapsedMicroseconds { get { return Units * Media.Common.Extensions.TimeSpan.TimeSpanExtensions.TotalMicroseconds(Timer.Frequency); } }
public double ElapsedMilliseconds { get { return Units * Timer.Frequency.TotalMilliseconds; } }
public double ElapsedSeconds { get { return Units * Timer.Frequency.TotalSeconds; } }
//public System.TimeSpan Elapsed { get { return System.TimeSpan.FromMilliseconds(ElapsedMilliseconds / System.TimeSpan.TicksPerMillisecond); } }
public System.TimeSpan Elapsed
{
get
{
switch (Units)
{
case 0: return System.TimeSpan.Zero;
default:
{
System.TimeSpan taken = System.DateTime.UtcNow - Timer.m_Started;
return taken.Add(new System.TimeSpan(Units * Timer.Frequency.Ticks));
//System.TimeSpan additional = new System.TimeSpan(Media.Common.Extensions.Math.MathExtensions.Clamp(Units, 0, Timer.Frequency.Ticks));
//return taken.Add(additional);
}
}
//////The maximum amount of times the timer can elapse in the given frequency
////double maxCount = (taken.TotalMilliseconds / Timer.Frequency.TotalMilliseconds) / ElapsedMilliseconds;
////if (Units > maxCount)
////{
//// //How many more times the event was fired than needed
//// double overage = (maxCount - Units);
//// additional = new System.TimeSpan(System.Convert.ToInt64(Media.Common.Extensions.Math.MathExtensions.Clamp(Units, overage, maxCount)));
//// //return taken.Add(new System.TimeSpan((long)Media.Common.Extensions.Math.MathExtensions.Clamp(Units, overage, maxCount)));
////}
//////return taken.Add(new System.TimeSpan(Units));
}
}
public void Start()
{
if (Enabled) return;
Units = 0;
//Create a Timer that will elapse every OneTick //`OneMicrosecond`
Timer = new Timer(Media.Common.Extensions.TimeSpan.TimeSpanExtensions.OneTick);
//Handle the event by incrementing count
Timer.Tick += Count;
Timer.Start();
}
public void Stop()
{
if (false == Enabled) return;
Timer.Stop();
Timer.Dispose();
}
void Count(ref long count) { ++Units; }
}
Finally, create something semi useful e.g. a Bus and then perhaps a virtual screen to emit data to the bus...
public abstract class Bus : Common.CommonDisposable
{
public readonly Timer Clock = new Timer(Common.Extensions.TimeSpan.TimeSpanExtensions.OneTick);
public Bus() : base(false) { Clock.Start(); }
}
public class ClockedBus : Bus
{
long FrequencyHz, Maximum, End;
readonly Queue<byte[]> Input = new Queue<byte[]>(), Output = new Queue<byte[]>();
readonly double m_Bias;
public ClockedBus(long frequencyHz, double bias = 1.5)
{
m_Bias = bias;
cache = Clock.m_Clock.InstructionsPerClockUpdate / 1000;
SetFrequency(frequencyHz);
Clock.Tick += Clock_Tick;
Clock.Start();
}
public void SetFrequency(long frequencyHz)
{
FrequencyHz = frequencyHz;
//Clock.m_Frequency = new TimeSpan(Clock.m_Clock.InstructionsPerClockUpdate / 1000);
//Maximum = System.TimeSpan.TicksPerSecond / Clock.m_Clock.InstructionsPerClockUpdate;
//Maximum = Clock.m_Clock.InstructionsPerClockUpdate / System.TimeSpan.TicksPerSecond;
Maximum = cache / (cache / FrequencyHz);
Maximum *= System.TimeSpan.TicksPerSecond;
Maximum = (cache / FrequencyHz);
End = Maximum * 2;
Clock.m_Frequency = new TimeSpan(Maximum);
if (cache < frequencyHz * m_Bias) throw new Exception("Cannot obtain stable clock");
Clock.Producer.Clear();
}
public override void Dispose()
{
ShouldDispose = true;
Clock.Tick -= Clock_Tick;
Clock.Stop();
Clock.Dispose();
base.Dispose();
}
~ClockedBus() { Dispose(); }
long sample = 0, steps = 0, count = 0, avg = 0, cache = 1;
void Clock_Tick(ref long ticks)
{
if (ShouldDispose == false && false == IsDisposed)
{
//Console.WriteLine("#ops=>" + Clock.m_Ops + " #ticks=>" + Clock.m_Ticks + " #Lticks=>" + ticks + "#=>" + Clock.m_Clock.Now.TimeOfDay + "#=>" + (Clock.m_Clock.Now - Clock.m_Clock.Created));
steps = sample;
sample = ticks;
++count;
System.ConsoleColor f = System.Console.ForegroundColor;
if (count <= Maximum)
{
System.Console.BackgroundColor = ConsoleColor.Yellow;
System.Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine("count=> " + count + "#=>" + Clock.m_Clock.Now.TimeOfDay + "#=>" + (Clock.m_Clock.Now - Clock.m_Clock.Created) + " - " + DateTime.UtcNow.ToString("MM/dd/yyyy hh:mm:ss.ffffff tt"));
avg = Maximum / count;
if (Clock.m_Clock.InstructionsPerClockUpdate / count > Maximum)
{
System.Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("---- Over InstructionsPerClockUpdate ----" + FrequencyHz);
}
}
else if (count >= End)
{
System.Console.BackgroundColor = ConsoleColor.Black;
System.Console.ForegroundColor = ConsoleColor.Blue;
avg = Maximum / count;
Console.WriteLine("avg=> " + avg + "#=>" + FrequencyHz);
count = 0;
}
}
}
//Read, Write at Frequency
}
public class VirtualScreen
{
TimeSpan RefreshRate;
bool VerticalSync;
int Width, Height;
Common.MemorySegment DisplayMemory, BackBuffer, DisplayBuffer;
}
Here is how I tested the StopWatch
internal class StopWatchTests
{
public void TestForOneMicrosecond()
{
System.Collections.Generic.List<System.Tuple<bool, System.TimeSpan, System.TimeSpan>> l = new System.Collections.Generic.List<System.Tuple<bool, System.TimeSpan, System.TimeSpan>>();
//Create a Timer that will elapse every `OneMicrosecond`
for (int i = 0; i <= 250; ++i) using (Media.Concepts.Classes.Stopwatch sw = new Media.Concepts.Classes.Stopwatch())
{
var started = System.DateTime.UtcNow;
System.Console.WriteLine("Started: " + started.ToString("MM/dd/yyyy hh:mm:ss.ffffff tt"));
//Define some amount of time
System.TimeSpan sleepTime = Media.Common.Extensions.TimeSpan.TimeSpanExtensions.OneMicrosecond;
System.Diagnostics.Stopwatch testSw = new System.Diagnostics.Stopwatch();
//Start
testSw.Start();
//Start
sw.Start();
while (testSw.Elapsed.Ticks < sleepTime.Ticks - (Common.Extensions.TimeSpan.TimeSpanExtensions.OneTick + Common.Extensions.TimeSpan.TimeSpanExtensions.OneTick).Ticks)
sw.Timer.m_Clock.NanoSleep(0); //System.Threading.Thread.SpinWait(0);
//Sleep the desired amount
//System.Threading.Thread.Sleep(sleepTime);
//Stop
testSw.Stop();
//Stop
sw.Stop();
var finished = System.DateTime.UtcNow;
var taken = finished - started;
var cc = System.Console.ForegroundColor;
System.Console.WriteLine("Finished: " + finished.ToString("MM/dd/yyyy hh:mm:ss.ffffff tt"));
System.Console.WriteLine("Sleep Time: " + sleepTime.ToString());
System.Console.WriteLine("Real Taken Total: " + taken.ToString());
if (taken > sleepTime)
{
System.Console.ForegroundColor = System.ConsoleColor.Red;
System.Console.WriteLine("Missed by: " + (taken - sleepTime));
}
else
{
System.Console.ForegroundColor = System.ConsoleColor.Green;
System.Console.WriteLine("Still have: " + (sleepTime - taken));
}
System.Console.ForegroundColor = cc;
System.Console.WriteLine("Real Taken msec Total: " + taken.TotalMilliseconds.ToString());
System.Console.WriteLine("Real Taken sec Total: " + taken.TotalSeconds.ToString());
System.Console.WriteLine("Real Taken μs Total: " + Media.Common.Extensions.TimeSpan.TimeSpanExtensions.TotalMicroseconds(taken).ToString());
System.Console.WriteLine("Managed Taken Total: " + sw.Elapsed.ToString());
System.Console.WriteLine("Diagnostic Taken Total: " + testSw.Elapsed.ToString());
System.Console.WriteLine("Diagnostic Elapsed Seconds Total: " + ((testSw.ElapsedTicks / (double)System.Diagnostics.Stopwatch.Frequency)));
//Write the rough amount of time taken in micro seconds
System.Console.WriteLine("Managed Time Estimated Taken: " + sw.ElapsedMicroseconds + "μs");
//Write the rough amount of time taken in micro seconds
System.Console.WriteLine("Diagnostic Time Estimated Taken: " + Media.Common.Extensions.TimeSpan.TimeSpanExtensions.TotalMicroseconds(testSw.Elapsed) + "μs");
System.Console.WriteLine("Managed Time Estimated Taken: " + sw.ElapsedMilliseconds);
System.Console.WriteLine("Diagnostic Time Estimated Taken: " + testSw.ElapsedMilliseconds);
System.Console.WriteLine("Managed Time Estimated Taken: " + sw.ElapsedSeconds);
System.Console.WriteLine("Diagnostic Time Estimated Taken: " + testSw.Elapsed.TotalSeconds);
if (sw.Elapsed < testSw.Elapsed)
{
System.Console.WriteLine("Faster than Diagnostic StopWatch");
l.Add(new System.Tuple<bool, System.TimeSpan, System.TimeSpan>(true, sw.Elapsed, testSw.Elapsed));
}
else if (sw.Elapsed > testSw.Elapsed)
{
System.Console.WriteLine("Slower than Diagnostic StopWatch");
l.Add(new System.Tuple<bool, System.TimeSpan, System.TimeSpan>(false, sw.Elapsed, testSw.Elapsed));
}
else
{
System.Console.WriteLine("Equal to Diagnostic StopWatch");
l.Add(new System.Tuple<bool, System.TimeSpan, System.TimeSpan>(true, sw.Elapsed, testSw.Elapsed));
}
}
int w = 0, f = 0;
var cc2 = System.Console.ForegroundColor;
foreach (var t in l)
{
if (t.Item1)
{
System.Console.ForegroundColor = System.ConsoleColor.Green;
++w; System.Console.WriteLine("Faster than Diagnostic StopWatch by: " + (t.Item3 - t.Item2));
}
else
{
System.Console.ForegroundColor = System.ConsoleColor.Red;
++f; System.Console.WriteLine("Slower than Diagnostic StopWatch by: " + (t.Item2 - t.Item3));
}
}
System.Console.ForegroundColor = System.ConsoleColor.Green;
System.Console.WriteLine("Wins = " + w);
System.Console.ForegroundColor = System.ConsoleColor.Red;
System.Console.WriteLine("Loss = " + f);
System.Console.ForegroundColor = cc2;
}
}

Cannot find exception's cause [duplicate]

I made a color palette with a jPanel and a JLabel array in it. At first it worked well, but then i put some other jLabels out of the JPanel and added them some events. Now I keep getting this error:
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.TimSort.mergeLo(TimSort.java:747)
at java.util.TimSort.mergeAt(TimSort.java:483)
at java.util.TimSort.mergeCollapse(TimSort.java:410)
at java.util.TimSort.sort(TimSort.java:214)
at java.util.TimSort.sort(TimSort.java:173)
at java.util.Arrays.sort(Arrays.java:659)
at java.util.Collections.sort(Collections.java:217)
at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(SortingFocusTraversalPolicy.java:136)
at javax.swing.SortingFocusTraversalPolicy.getFocusTraversalCycle(SortingFocusTraversalPolicy.java:110)
at javax.swing.SortingFocusTraversalPolicy.getFirstComponent(SortingFocusTraversalPolicy.java:435)
at javax.swing.LayoutFocusTraversalPolicy.getFirstComponent(LayoutFocusTraversalPolicy.java:166)
at javax.swing.SortingFocusTraversalPolicy.getDefaultComponent(SortingFocusTraversalPolicy.java:515)
at java.awt.FocusTraversalPolicy.getInitialComponent(FocusTraversalPolicy.java:169)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:380)
at java.awt.Component.dispatchEventImpl(Component.java:4731)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
at java.awt.SequencedEvent.dispatch(SequencedEvent.java:116)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
I tried to remove everything i've done after first time i got this error, but still keep getting it. When i change the layout from GridLayout to anything else, then the error disappears, but the code becomes useless. So i need GridLayout. When i move everything in that JPanel to another JPanel, the error also goes away. But when i remove the first JPanel, error comes back.
By the way, the program works, but it's not pleasent to keep getting errors...
Edit: When i use less than 225 color, there's no error. I'm really curious about what's happening. Any explanation would be appreciated...

It seems to me like you've hit a bug in the JDK since the error seems to come from Swing classes.
Options:
Define the property java.util.Arrays.useLegacyMergeSort as true. Either using in your code the line
System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");
before any Swing code. As the first line in the main method should work.
Or adding
-Djava.util.Arrays.useLegacyMergeSort=true
to your starting options (in the console, or in the project properties in an IDE, Ant script, etc.)
Upgrade your JDK and see if the problem goes away
Downgrade to Java 6

Report my findings:
-Djava.util.Arrays.useLegacyMergeSort=true
works
but
System.setProperty("java.util.Arrays.useLegacyMergeSort", "true");
does not work.
It is due to the fact that in JDK Arrays.class
static final class LegacyMergeSort {
private static final boolean userRequested = ...
It is a static variable which is defined when jvm starts. Setting System property in the program will have no effect if the class has been loaded into jvm.
I have beeing monitoring the LegacyMergeSort.userRequested variable, and the findings confirmed with above statement.
Update:
The program must set system properties before java.util.Arrays is loaded to classloader.
Otherwise, once it is loaded, setting the properties is not going to be useful due to the reason mentioned above.
Make sure nothing else loaded Arrays.class:
By putting following code to your program to test:
java.lang.reflect.Method m = ClassLoader.class.getDeclaredMethod("findLoadedClass", new Class[] { String.class });
m.setAccessible(true);
ClassLoader cl = ClassLoader.getSystemClassLoader();
Object test1 = m.invoke(cl, "java.util.Arrays");
System.out.println("test1 loaded? ->" + (test1 != null));

[Update]
This solution unfortunately is not guaranteed to solve the problem in all cases. It is not enough to patch the default SortingFocusTraversalPolicy
of the KeyboardFocusManager.
I recommend to read the answer by Robin Loxley below, including his Update.
[/Update]
java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.TimSort.mergeHi(TimSort.java:868)
This problem is caused by a bug in javax.swing.LayoutComparator.
The following class installs a fixed version of javax.swing.LayoutComparator, which does not violate the contract of Comparator<Component>. This (or any other) fixed version of javax.swing.LayoutComparator should be submitted to Oracle by some Oracle contributor.
package ...;
import java.awt.Component;
import java.awt.ComponentOrientation;
import java.awt.FocusTraversalPolicy;
import java.awt.KeyboardFocusManager;
import java.awt.Window;
import java.lang.reflect.Field;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.ListIterator;
import javax.swing.JRootPane;
import javax.swing.SortingFocusTraversalPolicy;
import javax.swing.UIManager;
/**
* Uses reflection to install a fixed version of {#link javax.swing.LayoutComparator} to solve the
* LayoutFocusTraversalPolicy/TimSort problem.
*
* <p>
* <code>java.lang.IllegalArgumentException: Comparison method violates its general contract!</code>
* <br/>
* {#code at java.util.TimSort.mergeHi(TimSort.java:868)}
* </p>
* <p>
* Usage: call {#code Class.forName(LayoutFocusTraversalPolicyTimSortBugFixer.class.getName())}
* before creating Swing components.
* </p>
*
* #author Burkhard Strauss
* #since Feb 2015
*/
public class LayoutFocusTraversalPolicyTimSortBugFixer
{
static
{
UIManager.getUI(new JRootPane()); // make Swing install the SortingFocusTraversalPolicy
final KeyboardFocusManager keyboardFocusManager = KeyboardFocusManager
.getCurrentKeyboardFocusManager();
final FocusTraversalPolicy focusTraversalPolicy = keyboardFocusManager
.getDefaultFocusTraversalPolicy();
boolean fixed = false;
if (focusTraversalPolicy instanceof SortingFocusTraversalPolicy)
{
try
{
final Field field = SortingFocusTraversalPolicy.class.getDeclaredField("comparator");
final boolean accessible = field.isAccessible();
try
{
field.setAccessible(true);
field.set(focusTraversalPolicy, new LayoutComparator());
fixed = true;
}
finally
{
field.setAccessible(accessible);
}
}
catch (final Exception e)
{
}
}
if (!fixed)
{
Loggers.getLoggerFor(LayoutFocusTraversalPolicyTimSortBugFixer.class).warn("could not fix the bug");
}
}
/**
* Fixed version of {#link javax.swing.LayoutComparator}.
* <p>
* Search for 'bugfix' in the code.
* </p>
*
* #author Burkhard Strauss
* #since Feb 2015
*/
#SuppressWarnings("serial")
private static class LayoutComparator implements Comparator<Component>, java.io.Serializable
{
private static final int ROW_TOLERANCE = 10;
private boolean horizontal = true;
private boolean leftToRight = true;
#SuppressWarnings("unused")
void setComponentOrientation(final ComponentOrientation orientation)
{
horizontal = orientation.isHorizontal();
leftToRight = orientation.isLeftToRight();
}
#Override
public int compare(Component a, Component b)
{
if (a == b)
{
return 0;
}
// Row/Column algorithm only applies to siblings. If 'a' and 'b'
// aren't siblings, then we need to find their most inferior
// ancestors which share a parent. Compute the ancestory lists for
// each Component and then search from the Window down until the
// hierarchy branches.
if (a.getParent() != b.getParent())
{
final LinkedList<Component> aAncestory = new LinkedList<Component>();
for (; a != null; a = a.getParent())
{
aAncestory.add(a);
if (a instanceof Window)
{
break;
}
}
if (a == null)
{
// 'a' is not part of a Window hierarchy. Can't cope.
throw new ClassCastException();
}
final LinkedList<Component> bAncestory = new LinkedList<Component>();
for (; b != null; b = b.getParent())
{
bAncestory.add(b);
if (b instanceof Window)
{
break;
}
}
if (b == null)
{
// 'b' is not part of a Window hierarchy. Can't cope.
throw new ClassCastException();
}
for (ListIterator<Component> aIter = aAncestory.listIterator(aAncestory.size()), bIter = bAncestory
.listIterator(bAncestory.size());;)
{
if (aIter.hasPrevious())
{
a = aIter.previous();
}
else
{
// a is an ancestor of b
return -1;
}
if (bIter.hasPrevious())
{
b = bIter.previous();
}
else
{
// b is an ancestor of a
return 1;
}
if (a != b)
{
break;
}
}
}
final int ax = a.getX(), ay = a.getY(), bx = b.getX(), by = b.getY();
int zOrder = a.getParent().getComponentZOrder(a) - b.getParent().getComponentZOrder(b);
{
//
// Here is the bugfix:
// Don't return 0 if a != b. This would violate the contract of
// Comparator<Component>.compare().
//
if (zOrder == 0)
{
zOrder = -1;
}
}
if (horizontal)
{
if (leftToRight)
{
// LT - Western Europe (optional for Japanese, Chinese, Korean)
if (Math.abs(ay - by) < ROW_TOLERANCE)
{
return (ax < bx) ? -1 : ((ax > bx) ? 1 : zOrder);
}
else
{
return (ay < by) ? -1 : 1;
}
}
else
{ // !leftToRight
// RT - Middle East (Arabic, Hebrew)
if (Math.abs(ay - by) < ROW_TOLERANCE)
{
return (ax > bx) ? -1 : ((ax < bx) ? 1 : zOrder);
}
else
{
return (ay < by) ? -1 : 1;
}
}
}
else
{ // !horizontal
if (leftToRight)
{
// TL - Mongolian
if (Math.abs(ax - bx) < ROW_TOLERANCE)
{
return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
}
else
{
return (ax < bx) ? -1 : 1;
}
}
else
{ // !leftToRight
// TR - Japanese, Chinese, Korean
if (Math.abs(ax - bx) < ROW_TOLERANCE)
{
return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
}
else
{
return (ax > bx) ? -1 : 1;
}
}
}
}
}
}

I just ran into the same error and spent a good amount of time tracking it down. To help others who run into this error it is important to know how to test TimSort. The checks that violate the transitivity contract and throw this error are deep in the algorithm and require a test to meet certain criteria before this problem can be reproduced.
Create a list with 32 or more objects.
Within that list, there needs to two or more runs.
Each run must contain 3 or more objects.
Once you meet those two criteria you can begin testing for this failure.
A run is defined as a sub-set of the list where each item is already in the desired ordered state.

It is not enough to patch LayoutComparator as suggerested above. This fix does not work in my case.
The issue was fixed in JDK 8 (8u45 at least).
SortingFocusTraversalPolicy to use legacy Merge Sort Method.

There is nothing wrong with the JDK.
I was facing the same issue since 2 days & finally got to know that bug was with my date-format.
In my API response few dates were in "dd-MM-yyyy HH:mm" format while few of them were in "dd/MM/yyyy HH:mm" format.
Same issue while comparing integers, May be your List is having some null values.
Here is my code, which is working like a charm
Collections.sort(root_array, new Comparator<RootResponseItem>(){
public int compare(RootResponseItem o1, RootResponseItem o2){
Date date1 = new Date();
String dtStart = o1.getSectors().get(0).getDeparture().getDate() + " " + o1.getSectors().get(0).getDeparture().getTime();
dtStart = dtStart.replaceAll("-","/");
SimpleDateFormat format = new SimpleDateFormat("dd/MM/yyyy HH:mm");
try {
date1 = format.parse(dtStart);
} catch (ParseException e) {
e.printStackTrace();
}
Date date2 = new Date();
String dtStart2 = o2.getSectors().get(0).getDeparture().getDate() + " " + o2.getSectors().get(0).getDeparture().getTime();
dtStart2 = dtStart2.replaceAll("-","/");
SimpleDateFormat format2 = new SimpleDateFormat("dd/MM/yyyy HH:mm");
try {
date2 = format2.parse(dtStart2);
} catch (ParseException e) {
e.printStackTrace();
}
return date1.compareTo(date2);
}
});

Java.lang.IllegalArgumentException: timeout value is negative

I have a thread that runs every day at a given hour.
it gives me this error message :
2014-05-21 03:57:06 [CRITICAL][AlertMgr] : maintenance :
java.lang.IllegalArgumentException: timeout value is negative
at java.lang.Thread.sleep(Native Method)
at
com.orca.pf.tc50.managerutilities.maintenance.MaintenanceManager.backgroundProcess(Unknown
Source)
at
com.orca.pf.tc50.managerutilities.maintenance.MaintenanceManager.access$000(Unknown
Source)
at
com.orca.pf.tc50.managerutilities.maintenance.MaintenanceManager$1.run(Unknown
Source)
at java.lang.Thread.run(Thread.java:745).
do you know what could cause this.
Thanks
private void backgroundProcess()
{
Calendar cal;
cal = Calendar.getInstance();
log.addHelpField("AlertMgr");
/*
* Synchronise le calendrier a 3:00AM
*/
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
if (cal.get(Calendar.HOUR_OF_DAY) > HOUR_START)
{
/*
* wait till tomorrow
*/
cal.set(Calendar.HOUR_OF_DAY, HOUR_START);
cal.add(Calendar.DAY_OF_YEAR, 1);
}
else
{
cal.set(Calendar.HOUR_OF_DAY, HOUR_START);
}
do
{
try
{
/*
* Calculate the time to wait
*/
long timeToWait = cal.getTimeInMillis() - System.currentTimeMillis();
Thread.sleep(timeToWait);
processAllEntries();
/*
* wait for tomorrow
*/
cal.add(Calendar.DAY_OF_YEAR, 1);
/*
* Clear
*/
Thread.interrupted();
}
catch(InterruptedException i)
{
Thread.currentThread().interrupt();
}
catch(Exception ex)
{
log.addException(LogLevel.CRITICAL, "maintenance", ex);
}
}
while(!th.isInterrupted());
}

I have a recommendation for you , rather than using Thread.sleep() try looking into Java Timer class . It would simplify your task of scheduling job every x hours. It will save you the effort to compute the amount of time to sleep to schedule the next task. This class lets you focus on the Business logic and takes care of the job of scheduling your task.

Java: SimpleDateFormat timestamp not updating

Evening,
I'm trying to create a timestamp for when an entity is added to my PriorityQueue using the following SimpleDate format: [yyyy/MM/dd - hh:mm:ss a] (Samples of results below)
Nano-second precision NOT 100% necessary
1: 2012/03/09 - 09:58:36 PM
Do you know how I can maintain an 'elapsed time' timestamp that shows when customers have been added to the PriorityQueue?
In the StackOverflow threads I've come across, most say to use System.nanoTime(); although I can't find resources online to implement this into a SimpleDateFormat. I have also consulted with colleagues.
Also, I apologize for not using syntax highlighting (if S.O supports it)
Code excerpt [unused methods omitted]:
<!-- language: java -->
package grocerystoresimulation;
/*****************************************************************************
* #import
*/
import java.util.PriorityQueue;
import java.util.Random;
import java.util.ArrayList;
import java.util.Date;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
/************************************************************************************
public class GroceryStoreSimulation {
/************************************************************************************
* #fields
*/
private PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
private Random rand = new Random(); //instantiate new Random object
private Date date = new Date();
private DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd - hh:mm:ss a");
private ArrayList<String> timeStamp = new ArrayList<String>(); //store timestamps
private int customersServed; //# of customers served during simulation
/************************************************************************************
* #constuctor
*/
public GroceryStoreSimulation(){
System.out.println("Instantiated new GroceryStoreSimulation # ["
+ dateFormat.format(date) + "]\n" + insertDivider());
//Program body
while(true){
try{
Thread.sleep(generateWaitTime());
newCustomer(customersServed);
} catch(InterruptedException e){/*Catch 'em all*/}
}
}
/************************************************************************************
* #param String ID
*/
private void newCustomer(int ID){
System.out.println("Customer # " + customersServed + " added to queue. . .");
pq.offer(ID); //insert element into PriorityQueue
customersServed++;
assignArrivalTime(ID); //call assignArrivalTime() method
} //newCustomer()
/************************************************************************************
* #param String ID
*/
private void assignArrivalTime(int ID){
timeStamp.add(ID + ": " + dateFormat.format(date));
System.out.println(timeStamp.get(customersServed-1));
} //assignArrivalTime()
/************************************************************************************
* #return int
*/
private int generateWaitTime(){
//Local variables
int Low = 1000; //1000ms
int High = 4000; //4000ms
int waitTime = rand.nextInt(High-Low) + Low;
System.out.println("Delaying for: " + waitTime);
return waitTime;
}
//***********************************************************************************
private static String insertDivider(){
return ("******************************************************************");
}
//***********************************************************************************
} //GroceryStoreSimulation
Problem:
Timestamp does not update, only represents initial runtime (see below)
Delaying by 1-4 seconds w/Thread.sleep(xxx) (pseudo-randomly generated)
Problem may be in the assignArrivalTime() method
Output:
run:
Instantiated new GroceryStoreSimulation # [2012/03/09 - 09:58:36 PM]
******************************************************************
Delaying for: 1697
Customer # 0 added to queue. . .
0: 2012/03/09 - 09:58:36 PM
Delaying for: 3550
Customer # 1 added to queue. . .
1: 2012/03/09 - 09:58:36 PM
Delaying for: 2009
Customer # 2 added to queue. . .
2: 2012/03/09 - 09:58:36 PM
Delaying for: 1925
BUILD STOPPED (total time: 8 seconds)
Thank you for your assistance, I hope my question is clear enough & I`ve followed your formatting guidelines sufficiently.

You have to use a new instance of Date everytime to get most recent timestamp.
private void assignArrivalTime(int ID){
timeStamp.add(ID + ": " + dateFormat.format(date));
------------------------------------------------^^^^
Try replacing date by new Date() in above line.