    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
    018package org.apache.commons.net.daytime;
    019
    020import java.io.BufferedReader;
    021import java.io.IOException;
    022import java.io.InputStreamReader;
    023
    024import org.apache.commons.net.SocketClient;
    025
    026/**
    027 * The DaytimeTCPClient class is a TCP implementation of a client for the
    028 * Daytime protocol described in RFC 867.  To use the class, merely
    029 * establish a connection with
    030 * {@link org.apache.commons.net.SocketClient#connect  connect }
    031 * and call {@link #getTime  getTime() } to retrieve the daytime
    032 * string, then
    033 * call {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
    034 * to close the connection properly.
    035 * @see DaytimeUDPClient
    036 */
    037public 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 final 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     *
    065     * @return The time string retrieved from the server.
    066     * @throws IOException  If an error occurs while fetching the time string.
    067     */
    068    public String getTime() throws IOException
    069    {
    070        int read;
    071        final StringBuilder result = new StringBuilder(buffer.length);
    072        BufferedReader reader;
    073
    074        reader = new BufferedReader(new InputStreamReader(_input_, getCharset()));
    075
    076        while (true)
    077        {
    078            read = reader.read(buffer, 0, buffer.length);
    079            if (read <= 0) {
    080                break;
    081            }
    082            result.append(buffer, 0, read);
    083        }
    084
    085        return result.toString();
    086    }
    087
    088}
    089