/* * 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.helpers;import java.io.Writer;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.DatagramPacket;import java.net.UnknownHostException;import java.net.SocketException;import java.io.IOException;import java.net.URL;import java.net.MalformedURLException;/**   SyslogWriter is a wrapper around the java.net.DatagramSocket class   so that it behaves like a java.io.Writer.   @since 0.7.3*/public class SyslogWriter extends Writer {  final int SYSLOG_PORT = 514;  /**   *  Host string from last constructed SyslogWriter.   *  @deprecated   */  static String syslogHost;    private InetAddress address;  private final int port;  private DatagramSocket ds;  /**   *  Constructs a new instance of SyslogWriter.   *  @param syslogHost host name, may not be null.  A port   *  may be specified by following the name or IPv4 literal address with   *  a colon and a decimal port number.  To specify a port with an IPv6   *  address, enclose the IPv6 address in square brackets before appending   *  the colon and decimal port number.   */  public  SyslogWriter(final String syslogHost) {    SyslogWriter.syslogHost = syslogHost;    if (syslogHost == null) {        throw new NullPointerException("syslogHost");    }        String host = syslogHost;    int urlPort = -1;        //    //  If not an unbracketed IPv6 address then    //      parse as a URL    //    if (host.indexOf("[") != -1 || host.indexOf(':') == host.lastIndexOf(':')) {        try {            URL url = new URL("http://" + host);            if (url.getHost() != null) {                host = url.getHost();                //   if host is a IPv6 literal, strip off the brackets                if(host.startsWith("[") && host.charAt(host.length() - 1) == ']') {                    host = host.substring(1, host.length() - 1);                }                urlPort = url.getPort();            }        } catch(MalformedURLException e) {      		LogLog.error("Malformed URL: will attempt to interpret as InetAddress.", e);        }    }        if (urlPort == -1) {        urlPort = SYSLOG_PORT;    }    port = urlPort;    try {            this.address = InetAddress.getByName(host);    }    catch (UnknownHostException e) {      LogLog.error("Could not find " + host +			 ". All logging will FAIL.", e);    }    try {      this.ds = new DatagramSocket();    }    catch (SocketException e) {      e.printStackTrace();      LogLog.error("Could not instantiate DatagramSocket to " + host +			 ". All logging will FAIL.", e);    }      }  public  void write(char[] buf, int off, int len) throws IOException {    this.write(new String(buf, off, len));  }    public  void write(final String string) throws IOException {    if(this.ds != null && this.address != null) {        byte[] bytes = string.getBytes();        //        //  syslog packets must be less than 1024 bytes        //        int bytesLength = bytes.length;        if (bytesLength >= 1024) {            bytesLength = 1024;        }        DatagramPacket packet = new DatagramPacket(bytes, bytesLength,                               address, port);        ds.send(packet);    }      }  public  void flush() {}  public void close() {      if (ds != null) {          ds.close();      }  }}