panda.net.time.TimeTCPClient Maven / Gradle / Ivy
package panda.net.time;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Date;
import panda.net.SocketClient;
/***
* The TimeTCPClient class is a TCP implementation of a client for the Time protocol described in
* RFC 868. To use the class, merely establish a connection with
* {@link panda.net.SocketClient#connect connect } and call either {@link #getTime getTime() } or
* {@link #getDate getDate() } to retrieve the time, then call
* {@link panda.net.SocketClient#disconnect disconnect } to close the connection properly.
*
* @see TimeUDPClient
***/
public final class TimeTCPClient extends SocketClient {
/*** The default time port. It is set to 37 according to RFC 868. ***/
public static final int DEFAULT_PORT = 37;
/***
* The number of seconds between 00:00 1 January 1900 and 00:00 1 January 1970. This value can
* be useful for converting time values to other formats.
***/
public static final long SECONDS_1900_TO_1970 = 2208988800L;
/***
* The default TimeTCPClient constructor. It merely sets the default port to
* DEFAULT_PORT .
***/
public TimeTCPClient() {
setDefaultPort(DEFAULT_PORT);
}
/***
* Retrieves the time from the server and returns it. The time is the number of seconds since
* 00:00 (midnight) 1 January 1900 GMT, as specified by RFC 868. This method reads the raw
* 32-bit big-endian unsigned integer from the server, converts it to a Java long, and returns
* the value.
*
* The server will have closed the connection at this point, so you should call
* {@link panda.net.SocketClient#disconnect disconnect } after calling this method. To retrieve
* another time, you must initiate another connection with
* {@link panda.net.SocketClient#connect connect } before calling getTime()
* again.
*
* @return The time value retrieved from the server.
* @exception IOException If an error occurs while fetching the time.
***/
public long getTime() throws IOException {
DataInputStream input;
input = new DataInputStream(_input_);
return (input.readInt() & 0xffffffffL);
}
/***
* Retrieves the time from the server and returns a Java Date containing the time converted to
* the local timezone.
*
* The server will have closed the connection at this point, so you should call
* {@link panda.net.SocketClient#disconnect disconnect } after calling this method. To retrieve
* another time, you must initiate another connection with
* {@link panda.net.SocketClient#connect connect } before calling getDate()
* again.
*
* @return A Date value containing the time retrieved from the server converted to the local
* timezone.
* @exception IOException If an error occurs while fetching the time.
***/
public Date getDate() throws IOException {
return new Date((getTime() - SECONDS_1900_TO_1970) * 1000L);
}
}