Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.net;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

SyslogOutputStream is a wrapper around the DatagramSocket class so that it behaves like an OutputStream. /**
 * SyslogOutputStream is a wrapper around the {@link DatagramSocket} class so that it
 * behaves like an {@link OutputStream}.
 */
public class SyslogOutputStream extends OutputStream {

    
The maximum length after which we discard the existing string buffer and
start anew.
/**
     * The maximum length after which we discard the existing string buffer and
     * start anew.
     */
    private static final int MAX_LEN = 1024;

    private InetAddress address;
    private DatagramSocket ds;
    private ByteArrayOutputStream baos = new ByteArrayOutputStream();
    final private int port;

    public SyslogOutputStream(String syslogHost, int port) throws UnknownHostException, SocketException {
        this.address = InetAddress.getByName(syslogHost);
        this.port = port;
        this.ds = new DatagramSocket();
    }

    public void write(byte[] byteArray, int offset, int len) throws IOException {
        baos.write(byteArray, offset, len);
    }

    public void flush() throws IOException {
        byte[] bytes = baos.toByteArray();
        DatagramPacket packet = new DatagramPacket(bytes, bytes.length, address, port);

        // clean up for next round
        if (baos.size() > MAX_LEN) {
            baos = new ByteArrayOutputStream();
        } else {
            baos.reset();
        }

        // after a failure, it can happen that bytes.length is zero
        // in that case, there is no point in sending out an empty message/
        if (bytes.length == 0) {
            return;
        }
        if (this.ds != null) {
            ds.send(packet);
        }

    }

    public void close() {
        address = null;
        ds = null;
    }

    public int getPort() {
        return port;
    }

    @Override
    public void write(int b) throws IOException {
        baos.write(b);
    }

    int getSendBufferSize() throws SocketException {
        return ds.getSendBufferSize();
    }
}