NetClock Component

Properties Methods Events Config Settings Errors

The NetClock component provides the current time in Greenwich Mean Time from an Internet Time Server.

Syntax

IPWorks.Netclock

Remarks

The NetClock component implements a standard Time Protocol client as specified in RFC 868, as well as an SNTP (Simple Network Time Protocol).

The address of the Time Server is provided in the TimeServer property. You get the time by calling the GetTime method.

The component also allows you to synchronize your system time with that of the TimeServer. This is done through the GetAndSetTime method. Calling GetAndSetTime will request the time from the server and then set the system clock to match it.

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.


Idle	The current status of the component.
LocalHost	The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
LocalTime	This property includes the time returned by the TimeServer converted to local time.
Protocol	This property is the protocol used by the component.
ServerTime	This property includes the time returned by the TimeServer .
Timeout	A timeout for the component.
TimePort	This property includes the User Datagram Protocol (UDP) port where the remote time server is listening.
TimeServer	This property includes the time server from which to request the time.

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.


config	Sets or retrieves a configuration setting.
doEvents	Processes events from the internal message queue.
getAndSetTime	This method is the same as the GetTime method, but the system clock is also set to the received time.
getTime	This method sends a time request to the TimeServer to get the current time.
interrupt	Interrupt the current method.
reset	This method resets the component.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.


Error	Fired when information is available about errors during data delivery.

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.


CaptureIPPacketInfo	Used to capture the packet information.
DelayHostResolution	Whether the hostname is resolved when RemoteHost is set.
DestinationAddress	Used to get the destination address from the packet information.
DontFragment	Used to set the Don't Fragment flag of outgoing packets.
LocalHost	The name of the local host through which connections are initiated or accepted.
LocalPort	The port in the local host where the component binds.
MaxPacketSize	The maximum length of the packets that can be received.
QOSDSCPValue	Used to specify an arbitrary QOS/DSCP setting (optional).
QOSTrafficType	Used to specify QOS/DSCP settings (optional).
ShareLocalPort	If set to True, allows more than one instance of the component to be active on the same local port.
UseConnection	Determines whether to use a connected socket.
UseIPv6	Whether or not to use IPv6.
AbsoluteTimeout	Determines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallData	Used to send extra data to the firewall.
InBufferSize	The size in bytes of the incoming queue of the socket.
OutBufferSize	The size in bytes of the outgoing queue of the socket.
BuildInfo	Information about the product's build.
GUIAvailable	Whether or not a message loop is available for processing events.
LicenseInfo	Information about the current license.
MaskSensitive	Whether sensitive data is masked in log messages.
UseDaemonThreads	Whether threads created by the component are daemon threads.
UseInternalSecurityAPI	Whether or not to use the system security libraries or an internal implementation.

Idle Property (NetClock Component)

The current status of the component.

Syntax


public boolean isIdle();

Default Value

True

Remarks

Idle will be False if the component is currently busy (communicating and/or waiting for an answer), and True at all other times.

This property is read-only.

LocalHost Property (NetClock Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax


public String getLocalHost();


public void setLocalHost(String localHost);

Default Value

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

LocalTime Property (NetClock Component)

This property includes the time returned by the TimeServer converted to local time.

Syntax


public String getLocalTime();

Default Value

Remarks

The server provides Greenwich Mean Time (GMT). This property contains the corresponding local time formatted as "MM/DD/YYYY HH:MM:SS" (where "HH" is in 24-hour format).

This property is read-only and not available at design time.

Protocol Property (NetClock Component)

This property is the protocol used by the component.

Syntax


public int getProtocol();


public void setProtocol(int protocol);

Enumerated values:
  public final static int tpTime = 0;

  public final static int tpSNTP = 1;

Default Value

Remarks

This property is the protocol used by the component. This property is used to specify which protocol the component will use to connect to the server. By default, this property is tpSNTP (1). The Time Protocol may be selected by setting this property to tpTimeProtocol (0).

ServerTime Property (NetClock Component)

This property includes the time returned by the TimeServer .

Syntax


public String getServerTime();

Default Value

Remarks

This property contains the time returned by the TimeServer. The time is given in Greenwich Mean Time (GMT) and is formatted as "MM/DD/YYYY HH:MM:SS GMT" (where "HH" is in 24-hour format).

For the corresponding local time, please consult the LocalTime property.

This property is read-only and not available at design time.

Timeout Property (NetClock Component)

A timeout for the component.

Syntax


public int getTimeout();


public void setTimeout(int timeout);

Default Value

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the component will wait for the operation to complete before returning control.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the component throws an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

TimePort Property (NetClock Component)

This property includes the User Datagram Protocol (UDP) port where the remote time server is listening.

Syntax


public int getTimePort();


public void setTimePort(int timePort);

Default Value

123

Remarks

This property is the UDP port on the TimeServer to which time requests are sent. If Protocol is set to tpTimeProtocol, the component will set this property to 37.

This property is not available at design time.

TimeServer Property (NetClock Component)

This property includes the time server from which to request the time.

Syntax


public String getTimeServer();


public void setTimeServer(String timeServer);

Default Value

"pool.ntp.org"

Remarks

This property contains the time server from which to request the time. This property should be set to a valid internet address of a time server. The server will reply with its current time (in Greenwich Mean Time).

When Protocol is set to SNTP another public server that may be used is "time.google.com".

Time requests are sent to port TimePort on the TimeServer.

Config Method (Netclock Component)

Sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DoEvents Method (Netclock Component)

Processes events from the internal message queue.

Syntax

public void doEvents();

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

GetAndSetTime Method (Netclock Component)

This method is the same as the GetTime method, but the system clock is also set to the received time.

Syntax

public void getAndSetTime();

Remarks

This method is similar to the GetTime method, but the system clock is also set to the received time (adjusted for timezone differences).

GetTime Method (Netclock Component)

This method sends a time request to the TimeServer to get the current time.

Syntax

public void getTime();

Remarks

This method sends a time request to the TimeServer on port 37. The reply is provided in the ServerTime property, and the equivalent local time is provided in the LocalTime property.

Interrupt Method (Netclock Component)

Interrupt the current method.

Syntax

public void interrupt();

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

Reset Method (Netclock Component)

This method resets the component.

Syntax

public void reset();

Remarks

This method will reset the component's properties to their default values.

Error Event (Netclock Component)

Fired when information is available about errors during data delivery.

Syntax

public class DefaultNetclockEventListener implements NetclockEventListener {
  ...
  public void error(NetclockErrorEvent e) {}
  ...
}

public class NetclockErrorEvent {
  public int errorCode;

  public String description;

}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component throws an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Config Settings (Netclock Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

UDP Config Settings

CaptureIPPacketInfo: Used to capture the packet information.

If this is set to true, the component will capture the IP packet information.

The default value for this setting is False.

Note: This setting is only available in Windows.

DelayHostResolution: Whether the hostname is resolved when RemoteHost is set.

This setting specifies whether a hostname is resolved immediately when RemoteHost is set. If true the component will resolve the hostname and the IP address will be present in the RemoteHost property. If false, the hostname is not resolved until needed by the component when a method to connect or send data is called. If desired, ResolveRemoteHost may called to manually resolve the value in RemoteHost at any time.

The default value is false.

DestinationAddress: Used to get the destination address from the packet information.

If CaptureIPPacketInfo is set to true, then this will be populated with the packet's destination address when a packet is received. This information will be accessible in the DataIn event.

Note: This setting is only available in Windows.

DontFragment: Used to set the Don't Fragment flag of outgoing packets.

When set to True, packets sent by the component will have the Don't Fragment flag set. The default value is False.

LocalHost: The name of the local host through which connections are initiated or accepted.

The LocalHost setting contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

If the component is connected, the LocalHost setting shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

LocalPort: The port in the local host where the component binds.

This must be set before a connection is attempted. It instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by LocalPort after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.

This; setting is useful when trying to connect to services that require a trusted port in the client side. An example is the remote shell (rsh) service in UNIX systems.

MaxPacketSize: The maximum length of the packets that can be received.

This setting specifies the maximum size of the datagrams that the component will accept without truncation.

QOSDSCPValue: Used to specify an arbitrary QOS/DSCP setting (optional).

UseConnection must be True to use this setting. This option allows you to specify an arbitrary DSCP value between 0 and 63. The default is 0. When set to the default value the component will not set a DSCP value.

Note: This setting uses the qWAVE API is only available on Windows 7, Windows Server 2008 R2, and later.

QOSTrafficType: Used to specify QOS/DSCP settings (optional).

UseConnection must be True to use this setting. You may specify either the text or integer values: BestEffort (0), Background (1), ExcellentEffort (2), AudioVideo (3), Voice (4), and Control (5).

Note: This setting uses the qWAVE API which is only available on Windows Vista and Windows Server 2008 or above.

Note: QOSTrafficType must be set before setting Active to true.

ShareLocalPort: If set to True, allows more than one instance of the component to be active on the same local port.

This option must be set before the component is activated through the Active property or it will have no effect.

The default value for this setting is False.

UseConnection: Determines whether to use a connected socket.

UseConnection specifies whether the component should use a connected socket or not. The connection is defined as an association in between the local address/port and the remote address/port. As such, this is not a connection in the traditional TCP sense. What it means is only that the component will send and receive data only to and from the specified destination.

The default value for this setting is False.

UseIPv6: Whether or not to use IPv6.

By default, the component expects an IPv4 address for local and remote host properties, and will create an IPv4 socket. To use IPv6 instead, set this to True.

Socket Config Settings

AbsoluteTimeout: Determines whether timeouts are inactivity timeouts or absolute timeouts.

If AbsoluteTimeout is set to True, any method which does not complete within Timeout seconds will be aborted. By default, AbsoluteTimeout is False, and the timeout is an inactivity timeout.

Note: This option is not valid for UDP ports.

FirewallData: Used to send extra data to the firewall.

When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g. headers for custom authentication schemes).

InBufferSize: The size in bytes of the incoming queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the InBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the InBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

OutBufferSize: The size in bytes of the outgoing queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the OutBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the OutBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

Base Config Settings

BuildInfo: Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

GUIAvailable: Whether or not a message loop is available for processing events.

In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the component does not attempt to process external events.

LicenseInfo: Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

Product: The product the license is for.
Product Key: The key the license was generated from.
License Source: Where the license was found (e.g., RuntimeLicense, License File).
License Type: The type of license installed (e.g., Royalty Free, Single Server).
Last Valid Build: The last valid build number for which the license will work.

MaskSensitive: Whether sensitive data is masked in log messages.

In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to true to mask sensitive data. The default is true.

This setting only works on these components: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

UseDaemonThreads: Whether threads created by the component are daemon threads.

If set to True (default), when the component creates a thread, the thread's Daemon property will be explicitly set to True. When set to False, the component will not set the Daemon property on the created thread. The default value is True.

UseInternalSecurityAPI: Whether or not to use the system security libraries or an internal implementation.

When set to false, the component will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to true tells the component to use the internal implementation instead of using the system security libraries.

This setting is set to false by default on all platforms.

Trappable Errors (Netclock Component)

NetClock Errors


	119 Error setting system time.
	301 Timeout while waiting for the server.
	305 An error occurred trying to change the system time.
	1000 Control is busy performing current action.

UDP Errors


	104 UDP is already Active.
	106 You cannot change the LocalPort while the component is Active.
	107 You cannot change the LocalHost at this time. A connection is in progress.
	109 The component must be Active for this operation.
	112 Cannot change MaxPacketSize while the component is Active.
	113 Cannot change ShareLocalPort option while the component is Active.
	114 Cannot change RemoteHost when UseConnection is set and the component Active.
	115 Cannot change RemotePort when UseConnection is set and the component is Active.
	116 RemotePort can't be zero when UseConnection is set. Please specify a valid service port number.
	117 Cannot change UseConnection while the component is Active.
	118 Message can't be longer than MaxPacketSize.
	119 Message too short.
	434 Unable to convert string to selected CodePage

SSL Errors


	270 Cannot load specified security library.
	271 Cannot open certificate store.
	272 Cannot find specified certificate.
	273 Cannot acquire security credentials.
	274 Cannot find certificate chain.
	275 Cannot verify certificate chain.
	276 Error during handshake.
	280 Error verifying certificate.
	281 Could not find client certificate.
	282 Could not find server certificate.
	283 Error encrypting data.
	284 Error decrypting data.

TCP/IP Errors


	10004 [10004] Interrupted system call.
	10009 [10009] Bad file number.
	10013 [10013] Access denied.
	10014 [10014] Bad address.
	10022 [10022] Invalid argument.
	10024 [10024] Too many open files.
	10035 [10035] Operation would block.
	10036 [10036] Operation now in progress.
	10037 [10037] Operation already in progress.
	10038 [10038] Socket operation on non-socket.
	10039 [10039] Destination address required.
	10040 [10040] Message too long.
	10041 [10041] Protocol wrong type for socket.
	10042 [10042] Bad protocol option.
	10043 [10043] Protocol not supported.
	10044 [10044] Socket type not supported.
	10045 [10045] Operation not supported on socket.
	10046 [10046] Protocol family not supported.
	10047 [10047] Address family not supported by protocol family.
	10048 [10048] Address already in use.
	10049 [10049] Can't assign requested address.
	10050 [10050] Network is down.
	10051 [10051] Network is unreachable.
	10052 [10052] Net dropped connection or reset.
	10053 [10053] Software caused connection abort.
	10054 [10054] Connection reset by peer.
	10055 [10055] No buffer space available.
	10056 [10056] Socket is already connected.
	10057 [10057] Socket is not connected.
	10058 [10058] Can't send after socket shutdown.
	10059 [10059] Too many references, can't splice.
	10060 [10060] Connection timed out.
	10061 [10061] Connection refused.
	10062 [10062] Too many levels of symbolic links.
	10063 [10063] File name too long.
	10064 [10064] Host is down.
	10065 [10065] No route to host.
	10066 [10066] Directory not empty
	10067 [10067] Too many processes.
	10068 [10068] Too many users.
	10069 [10069] Disc Quota Exceeded.
	10070 [10070] Stale NFS file handle.
	10071 [10071] Too many levels of remote in path.
	10091 [10091] Network subsystem is unavailable.
	10092 [10092] WINSOCK DLL Version out of range.
	10093 [10093] Winsock not loaded yet.
	11001 [11001] Host not found.
	11002 [11002] Non-authoritative 'Host not found' (try again or check DNS setup).
	11003 [11003] Non-recoverable errors: FORMERR, REFUSED, NOTIMP.
	11004 [11004] Valid name, no data record (check DNS setup).