    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017
    018    package org.apache.commons.net.time;
    019
    020    import java.io.DataInputStream;
    021    import java.io.IOException;
    022    import java.util.Date;
    023
    024    import org.apache.commons.net.SocketClient;
    025
    026    /***
    027     * The TimeTCPClient class is a TCP implementation of a client for the
    028     * Time protocol described in RFC 868.  To use the class, merely
    029     * establish a connection with
    030     * {@link org.apache.commons.net.SocketClient#connect  connect }
    031     * and call either {@link #getTime  getTime() } or
    032     * {@link #getDate  getDate() } to retrieve the time, then
    033     * call {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
    034     * to close the connection properly.
    035     * <p>
    036     * <p>
    037     * @see TimeUDPClient
    038     ***/
    039
    040    public final class TimeTCPClient extends SocketClient
    041    {
    042        /*** The default time port.  It is set to 37 according to RFC 868. ***/
    043        public static final int DEFAULT_PORT = 37;
    044
    045        /***
    046         * The number of seconds between 00:00 1 January 1900 and
    047         * 00:00 1 January 1970.  This value can be useful for converting
    048         * time values to other formats.
    049         ***/
    050        public static final long SECONDS_1900_TO_1970 = 2208988800L;
    051
    052        /***
    053         * The default TimeTCPClient constructor.  It merely sets the default
    054         * port to <code> DEFAULT_PORT </code>.
    055         ***/
    056        public TimeTCPClient ()
    057        {
    058            setDefaultPort(DEFAULT_PORT);
    059        }
    060
    061        /***
    062         * Retrieves the time from the server and returns it.  The time
    063         * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
    064         * as specified by RFC 868.  This method reads the raw 32-bit big-endian
    065         * unsigned integer from the server, converts it to a Java long, and
    066         * returns the value.
    067         * <p>
    068         * The server will have closed the connection at this point, so you should
    069         * call
    070         * {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
    071         * after calling this method.  To retrieve another time, you must
    072         * initiate another connection with
    073         * {@link org.apache.commons.net.SocketClient#connect  connect }
    074         * before calling <code> getTime() </code> again.
    075         * <p>
    076         * @return The time value retrieved from the server.
    077         * @exception IOException  If an error occurs while fetching the time.
    078         ***/
    079        public long getTime() throws IOException
    080        {
    081            DataInputStream input;
    082            input = new DataInputStream(_input_);
    083            return (input.readInt() & 0xffffffffL);
    084        }
    085
    086        /***
    087         * Retrieves the time from the server and returns a Java Date
    088         * containing the time converted to the local timezone.
    089         * <p>
    090         * The server will have closed the connection at this point, so you should
    091         * call
    092         * {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
    093         * after calling this method.  To retrieve another time, you must
    094         * initiate another connection with
    095         * {@link org.apache.commons.net.SocketClient#connect  connect }
    096         * before calling <code> getDate() </code> again.
    097         * <p>
    098         * @return A Date value containing the time retrieved from the server
    099         *     converted to the local timezone.
    100         * @exception IOException  If an error occurs while fetching the time.
    101         ***/
    102        public Date getDate() throws IOException
    103        {
    104            return new Date((getTime() - SECONDS_1900_TO_1970)*1000L);
    105        }
    106
    107    }
    108