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/*
* 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.net;
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 org.apache.log4j.helpers.LogLog;
/**
* DatagramStringWriter is a wrapper around the java.net.DatagramSocket class
* so that it behaves like a java.io.Writer.
*/
public class DatagramStringWriter extends Writer {
static final int SYSLOG_PORT = 514;
private int port;
private String host;
private String encoding;
private String prefix;
private InetAddress address;
private DatagramSocket ds;
/**
* This constructor assumes that it is sending to a remote syslog daemon
* on the normal syslog port (514), and uses the default platform character
* encoding when converting the message string to a byte sequence.
*/
public
DatagramStringWriter(String host) {
this(host, SYSLOG_PORT, null, null);
}
/**
* This constructor sends messages to the specified host and port, and
* uses the default platform character encoding when converting the message
* string to a byte sequence.
*/
public
DatagramStringWriter(String host, int port) {
this(host, port, null, null);
}
/**
* This constructor sends messages to the specified host and port, and
* uses the specified character encoding when converting the message
* string to a byte sequence.
*/
public
DatagramStringWriter(String host, int port, String encoding) {
this(host, port, null, null);
}
/**
* This constructor sends messages to the specified host and port, and
* uses the specified character encoding when converting the message
* string to a byte sequence; the specified prefix (which may be null)
* is prepended to each message.
*/
public
DatagramStringWriter(String host, int port, String encoding, String prefix) {
this.host = host;
this.port = port;
this.encoding = encoding;
this.prefix = prefix;
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(String string) throws IOException {
if (prefix != null) {
string = prefix + string;
}
byte[] rawData;
if (this.encoding == null)
{
// convert to byte sequence using platform's default encoding
rawData = string.getBytes();
}
else
{
// convert to specified encoding - which may be sequence of
// 8-bit chars, or multi-byte encodings like UTF-8 or UTF-16.
// The receiving end had better be expecting whatever encoding
// is used here on the sending end!
rawData = string.getBytes(encoding);
}
DatagramPacket packet =
new DatagramPacket(
rawData,
rawData.length,
address,
port);
if(this.ds != null)
{
ds.send(packet);
}
else
{
LogLog.error(
"write: failed to create DatagramPacket");
}
}
public
void flush() {}
public
void close() {}
/**
* Set a string to be prefixed to every message sent by this Writer.
* For example, this method could be used to prepend a syslog
* facility/priority code on the front of each message.
* <p>
* Note that this method is not synchronised, so should not be called in
* a situation where other threads may be logging messages at the same
* moment.
* <p>
* @param prefix may be a prefix string, or null which indicates no
* prefix should be added.
*/
public
void setPrefix(String prefix){
this.prefix = prefix;
}
}
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