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.BufferedReader;
019    import java.io.IOException;
020    import java.io.InputStreamReader;
021    
022    /***
023     * The DaytimeTCPClient class is a TCP implementation of a client for the
024     * Daytime protocol described in RFC 867.  To use the class, merely
025     * establish a connection with
026     * {@link org.apache.commons.net.SocketClient#connect  connect }
027     * and call {@link #getTime  getTime() } to retrieve the daytime
028     * string, 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 DaytimeUDPClient
035     ***/
036    
037    public final class DaytimeTCPClient extends SocketClient
038    {
039        /*** The default daytime port.  It is set to 13 according to RFC 867. ***/
040        public static final int DEFAULT_PORT = 13;
041    
042        // Received dates will likely be less than 64 characters.
043        // This is a temporary buffer used while receiving data.
044        private char[] __buffer = new char[64];
045    
046        /***
047         * The default DaytimeTCPClient constructor.  It merely sets the default
048         * port to <code> DEFAULT_PORT </code>.
049         ***/
050        public DaytimeTCPClient ()
051        {
052            setDefaultPort(DEFAULT_PORT);
053        }
054    
055        /***
056         * Retrieves the time string from the server and returns it.  The
057         * server will have closed the connection at this point, so you should
058         * call
059         * {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
060         * after calling this method.  To retrieve another time, you must
061         * initiate another connection with
062         * {@link org.apache.commons.net.SocketClient#connect  connect }
063         * before calling <code> getTime() </code> again.
064         * <p>
065         * @return The time string retrieved from the server.
066         * @exception IOException  If an error occurs while fetching the time string.
067         ***/
068        public String getTime() throws IOException
069        {
070            int read;
071            StringBuffer result = new StringBuffer(__buffer.length);
072            BufferedReader reader;
073    
074            reader = new BufferedReader(new InputStreamReader(_input_));
075    
076            while (true)
077            {
078                read = reader.read(__buffer, 0, __buffer.length);
079                if (read <= 0)
080                    break;
081                result.append(__buffer, 0, read);
082            }
083    
084            return result.toString();
085        }
086    
087    }
088