/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.varia;

import org.apache.log4j.Logger;
import org.apache.log4j.BasicConfigurator;

import java.io.IOException;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;

/**
 * A simple application to send roll over messages to a potentially remote
 * {@link ExternallyRolledFileAppender}.
 * 
 * <p>
 * It takes two arguments, the <code>host_name</code> and
 * <code>port_number</code> where the <code>ExternallyRolledFileAppender</code>
 * is listening.
 * 
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @since version 0.9.0
 */
public class Roller {

    static Logger cat = Logger.getLogger(Roller.class);

    static String host;
    static int port;

    // Static class.
    Roller() {
    }

    /**
     * Send a "RollOver" message to <code>ExternallyRolledFileAppender</code> on
     * <code>host</code> and <code>port</code>.
     * 
     */
    public static void main(String argv[]) {

	BasicConfigurator.configure();

	if (argv.length == 2)
	    init(argv[0], argv[1]);
	else
	    usage("Wrong number of arguments.");

	roll();
    }

    static void usage(String msg) {
	System.err.println(msg);
	System.err.println("Usage: java " + Roller.class.getName() + "host_name port_number");
	System.exit(1);
    }

    static void init(String hostArg, String portArg) {
	host = hostArg;
	try {
	    port = Integer.parseInt(portArg);
	} catch (java.lang.NumberFormatException e) {
	    usage("Second argument " + portArg + " is not a valid integer.");
	}
    }

    static void roll() {
	try {
	    Socket socket = new Socket(host, port);
	    DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
	    DataInputStream dis = new DataInputStream(socket.getInputStream());
	    dos.writeUTF(ExternallyRolledFileAppender.ROLL_OVER);
	    String rc = dis.readUTF();
	    if (ExternallyRolledFileAppender.OK.equals(rc)) {
		cat.info("Roll over signal acknowledged by remote appender.");
	    } else {
		cat.warn("Unexpected return code " + rc + " from remote entity.");
		System.exit(2);
	    }
	} catch (IOException e) {
	    cat.error("Could not send roll signal on host " + host + " port " + port + " .", e);
	    System.exit(2);
	}
	System.exit(0);
    }
}
