src/java/org/apache/log4j/helpers/SyslogWriter.java

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 *
 * Licensed 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.IOException;
import java.io.Writer;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;


/**
   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;
  String syslogHost;
  private InetAddress address;
  private DatagramSocket ds;

  private Logger logger = LogManager.getLogger(SyslogWriter.class);
  StringBuffer buf = new StringBuffer();
  
  public SyslogWriter(String syslogHost) {
    this.syslogHost = syslogHost;

    try {
      this.address = InetAddress.getByName(syslogHost);
    } catch (UnknownHostException e) {
      logger.error(
        "Could not find " + syslogHost + ". All logging will FAIL.", e);
    }

    try {
      this.ds = new DatagramSocket();
    } catch (SocketException e) {
      e.printStackTrace();
      logger.error(
        "Could not instantiate DatagramSocket to " + syslogHost
        + ". All logging will FAIL.", e);
    }
  }

  public void write(char[] charArray, int offset, int len) throws IOException {
    buf.append(charArray, offset, len);
  }

  public void write(String str) throws IOException {
    buf.append(str);
   
  }

  public void flush() throws IOException {
    logger.debug("Writing out [{}]", buf);
    byte[] bytes = buf.toString().getBytes();
    DatagramPacket packet =
      new DatagramPacket(bytes, bytes.length, address, SYSLOG_PORT);

    if (this.ds != null) {
      ds.send(packet);
    }
    // clean up for next time
    buf.setLength(0);
  }

  public void close() {
  }
}