    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 Daytime protocol described in RFC 867. To use the class, merely establish a connection
    028 * with {@link org.apache.commons.net.SocketClient#connect connect } and call {@link #getTime getTime() } to retrieve the daytime string, then call
    029 * {@link org.apache.commons.net.SocketClient#disconnect disconnect } to close the connection properly.
    030 *
    031 * @see DaytimeUDPClient
    032 */
    033public final class DaytimeTCPClient extends SocketClient {
    034    /** The default daytime port. It is set to 13 according to RFC 867. */
    035    public static final int DEFAULT_PORT = 13;
    036
    037    // Received dates will likely be less than 64 characters.
    038    // This is a temporary buffer used while receiving data.
    039    private final char[] buffer = new char[64];
    040
    041    /**
    042     * The default DaytimeTCPClient constructor. It merely sets the default port to <code> DEFAULT_PORT </code>.
    043     */
    044    public DaytimeTCPClient() {
    045        setDefaultPort(DEFAULT_PORT);
    046    }
    047
    048    /**
    049     * Retrieves the time string from the server and returns it. The server will have closed the connection at this point, so you should call
    050     * {@link org.apache.commons.net.SocketClient#disconnect disconnect } after calling this method. To retrieve another time, you must initiate another
    051     * connection with {@link org.apache.commons.net.SocketClient#connect connect } before calling <code> getTime() </code> again.
    052     *
    053     * @return The time string retrieved from the server.
    054     * @throws IOException If an error occurs while fetching the time string.
    055     */
    056    public String getTime() throws IOException {
    057        int read;
    058        final StringBuilder result = new StringBuilder(buffer.length);
    059        final BufferedReader reader;
    060
    061        reader = new BufferedReader(new InputStreamReader(_input_, getCharset()));
    062
    063        while (true) {
    064            read = reader.read(buffer, 0, buffer.length);
    065            if (read <= 0) {
    066                break;
    067            }
    068            result.append(buffer, 0, read);
    069        }
    070
    071        return result.toString();
    072    }
    073
    074}