001: /*
002: * Copyright 2001-2005 The Apache Software Foundation
003: *
004: * Licensed under the Apache License, Version 2.0 (the "License");
005: * you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at
007: *
008: * http://www.apache.org/licenses/LICENSE-2.0
009: *
010: * Unless required by applicable law or agreed to in writing, software
011: * distributed under the License is distributed on an "AS IS" BASIS,
012: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013: * See the License for the specific language governing permissions and
014: * limitations under the License.
015: */
016: package org.apache.commons.net;
017:
018: import java.io.IOException;
019: import java.util.Date;
020: import java.io.DataInputStream;
021:
022: /***
023: * The TimeTCPClient class is a TCP implementation of a client for the
024: * Time protocol described in RFC 868. To use the class, merely
025: * establish a connection with
026: * {@link org.apache.commons.net.SocketClient#connect connect }
027: * and call either {@link #getTime getTime() } or
028: * {@link #getDate getDate() } to retrieve the time, then
029: * call {@link org.apache.commons.net.SocketClient#disconnect disconnect }
030: * to close the connection properly.
031: * <p>
032: * <p>
033: * @author Daniel F. Savarese
034: * @see TimeUDPClient
035: ***/
036:
037: public final class TimeTCPClient extends SocketClient {
038: /*** The default time port. It is set to 37 according to RFC 868. ***/
039: public static final int DEFAULT_PORT = 37;
040:
041: /***
042: * The number of seconds between 00:00 1 January 1900 and
043: * 00:00 1 January 1970. This value can be useful for converting
044: * time values to other formats.
045: ***/
046: public static final long SECONDS_1900_TO_1970 = 2208988800L;
047:
048: /***
049: * The default TimeTCPClient constructor. It merely sets the default
050: * port to <code> DEFAULT_PORT </code>.
051: ***/
052: public TimeTCPClient() {
053: setDefaultPort(DEFAULT_PORT);
054: }
055:
056: /***
057: * Retrieves the time from the server and returns it. The time
058: * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
059: * as specified by RFC 868. This method reads the raw 32-bit big-endian
060: * unsigned integer from the server, converts it to a Java long, and
061: * returns the value.
062: * <p>
063: * The server will have closed the connection at this point, so you should
064: * call
065: * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
066: * after calling this method. To retrieve another time, you must
067: * initiate another connection with
068: * {@link org.apache.commons.net.SocketClient#connect connect }
069: * before calling <code> getTime() </code> again.
070: * <p>
071: * @return The time value retrieved from the server.
072: * @exception IOException If an error occurs while fetching the time.
073: ***/
074: public long getTime() throws IOException {
075: DataInputStream input;
076: input = new DataInputStream(_input_);
077: return (long) (input.readInt() & 0xffffffffL);
078: }
079:
080: /***
081: * Retrieves the time from the server and returns a Java Date
082: * containing the time converted to the local timezone.
083: * <p>
084: * The server will have closed the connection at this point, so you should
085: * call
086: * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
087: * after calling this method. To retrieve another time, you must
088: * initiate another connection with
089: * {@link org.apache.commons.net.SocketClient#connect connect }
090: * before calling <code> getDate() </code> again.
091: * <p>
092: * @return A Date value containing the time retrieved from the server
093: * converted to the local timezone.
094: * @exception IOException If an error occurs while fetching the time.
095: ***/
096: public Date getDate() throws IOException {
097: return new Date((getTime() - SECONDS_1900_TO_1970) * 1000L);
098: }
099:
100: }
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