net.sourceforge.jsdp
Class Time

java.lang.Object
  net.sourceforge.jsdp.Time

All Implemented Interfaces:

Serializable, Cloneable, Field

public class Time
extends Object
implements Field

A Time represents a t=<field value> field contained in a SDP message. A time field specifies the start and stop times for a SDP announce.

Since:

0.1.0

Version:

1.0

Author:

Claudio Di Vita

See Also:

Serialized Form

Field Summary

static long	NTP_CONSTANT Constant used to translate between NTP time used in SDP and "native" Java time.
protected long	start The session start time
protected long	stop The session stop time

Fields inherited from interface net.sourceforge.jsdp.Field

ATTRIBUTE_FIELD, BANDWITH_FIELD, CONNECTION_FIELD, EMAIL_FIELD, END_OF_FIELD, INFORMATION_FIELD, KEY_FIELD, MEDIA_FIELD, ORIGIN_FIELD, PHONE_FIELD, REPEAT_TIME_FIELD, SESSION_NAME_FIELD, TIME_FIELD, TIMEZONE_FIELD, URI_FIELD, VERSION_FIELD

Constructor Summary

Time()
Creates a new Time.

Time(Date start, Date stop)
Creates a new Time.

Time(long start, long stop)
Creates a new Time.

Method Summary

Object	clone() Returns a clone of this field.
static Date	getDateFromNtp(long ntpTime) Returns a Date object for a given NTP date value.
static long	getNTP(Date date) Transform a Date in a long containing the corresponding NTP value.
Date	getStartTime() Returns the start time of the session.
Date	getStopTime() Returns the stop time of the session.
char	getType() Returns the type character for the field.
static boolean	isValidNTP(String input) Indicates if a string represents a valid NTP value.
boolean	isZero() Returns whether the start and stop times were set to zero (in NTP).
static Time	parse(String field) Parse an input string and constructs the equivalent time field.
void	setStartTime(Date start) Sets the start time of the session.
void	setStartTime(long start) Sets the start time of the session.
void	setStopTime(Date stop) Sets the stop time of the session.
void	setStopTime(long stop) Sets the stop time of the session.
void	setZero() Sets the start and stop times to zero (in NTP).
String	toString() Returns a string representation of the field.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

NTP_CONSTANT

public static final long NTP_CONSTANT

Constant used to translate between NTP time used in SDP and "native" Java time. NTP time is defined as the number of seconds relative to midnight, January 1, 1900 and Java time is measured in number of milliseconds since midnight, January 1, 1970 UTC (see System.currentTimeMillis()).

The value of this constant is 2208988800L. It can be used to convert between NTP and Java time using the following formulas:

• ntpTime = (javaTime/1000) + Time.NTP_CONST;
• javaTime = (ntpTime - Time.NTP_CONST) * 1000;

The Network Time Protocol (NTP) is defined in RFC 1305.

See Also:

Constant Field Values

start

protected long start

The session start time

stop

protected long stop

The session stop time

Constructor Detail

Time

public Time()

Creates a new Time. The session start and stop time are set to zero.

Time

public Time(Date start,
            Date stop)
     throws SDPException

Creates a new Time.

Parameters:

start - the session start time

stop - the session stop time

Throws:

SDPException - if the NTP representation of the session start and/or stop time are negative

Time

public Time(long start,
            long stop)
     throws SDPException

Creates a new Time.

Parameters:

start - the session start time

stop - the session stop time

Throws:

SDPException - if the session start or stop time are negative

Method Detail

getDateFromNtp

public static Date getDateFromNtp(long ntpTime)

Returns a Date object for a given NTP date value.

Parameters:

ntpTime - the NTP date value

Returns:

a new Date instance that represents the given NTP date value

getNTP

public static long getNTP(Date date)

Transform a Date in a long containing the corresponding NTP value.

Parameters:

date - the Date to transform

Returns:

the NTP value of the given date

isValidNTP

public static boolean isValidNTP(String input)

Indicates if a string represents a valid NTP value.

Parameters:

input - the string to test

Returns:

true if the specified string represents a valid NTP value, false otherwise

parse

public static Time parse(String field)
                  throws SDPParseException

Parse an input string and constructs the equivalent time field.

Parameters:

field - the string to parse

Returns:

a new Time instance

Throws:

SDPParseException - if an error occurs while parsing

clone

public Object clone()

Returns a clone of this field.

Specified by:

clone in interface Field

Overrides:

clone in class Object

Returns:

a clone of this field

getStartTime

public Date getStartTime()

Returns the start time of the session.

Returns:

the start time of the session

getStopTime

public Date getStopTime()

Returns the stop time of the session.

Returns:

the stop time of the session

getType

public char getType()

Returns the type character for the field.

Specified by:

getType in interface Field

Returns:

the field type character: t

isZero

public boolean isZero()

Returns whether the start and stop times were set to zero (in NTP).

Returns:

true if the start and stop times are set to zero, false otherwise

setStartTime

public void setStartTime(Date start)
                  throws SDPException

Sets the start time of the session.

Parameters:

start - the start time

Throws:

SDPException - if the date is null or if his NTP representation is negative

setStartTime

public void setStartTime(long start)
                  throws SDPException

Sets the start time of the session.

Parameters:

start - The start time

Throws:

SDPException - If the start time is negative

setStopTime

public void setStopTime(Date stop)
                 throws SDPException

Sets the stop time of the session.

Parameters:

stop - the stop time

Throws:

SDPException - if the date is null or his NTP representation is negative

setStopTime

public void setStopTime(long stop)
                 throws SDPException

Sets the stop time of the session.

Parameters:

stop - the stop time

Throws:

SDPException - if the stop time is negative

setZero

public void setZero()

Sets the start and stop times to zero (in NTP).

toString

public String toString()

Returns a string representation of the field. The representation has the form: t=<start time> <stop time>.

Specified by:

toString in interface Field

Overrides:

toString in class Object

Returns:

the string representation of the field