com.nesscomputing.syslog4j.Syslog Maven / Gradle / Ivy
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Syslog4j provides client and server implementations of the BSD Syslog protocol (RFC 3164) and the structured syslog" protocol (RFC5424).
/**
*
* (C) Copyright 2008-2011 syslog4j.org
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the GNU Lesser General Public License
* (LGPL) version 2.1 which accompanies this distribution, and is available at
* http://www.gnu.org/licenses/lgpl-2.1.html
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package com.nesscomputing.syslog4j;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.StringUtils;
import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;
import com.nesscomputing.syslog4j.impl.net.tcp.TCPNetSyslogConfig;
import com.nesscomputing.syslog4j.impl.net.udp.UDPNetSyslogConfig;
import com.nesscomputing.syslog4j.impl.unix.UnixSyslogConfig;
import com.nesscomputing.syslog4j.impl.unix.socket.UnixSocketSyslogConfig;
import com.nesscomputing.syslog4j.util.OSDetectUtility;
import com.nesscomputing.syslog4j.util.SyslogUtility;
/**
* This class provides a Singleton interface for Syslog4j client implementations.
*
* Usage examples:
*
* Direct
*
* Syslog.getInstance("udp").info("log message");
*
*
* Via Instance
*
* SyslogIF syslog = Syslog.getInstance("udp");
* syslog.info();
*
*
* Syslog4j is licensed under the Lesser GNU Public License v2.1. A copy
* of the LGPL license is available in the META-INF folder in all
* distributions of Syslog4j and in the base directory of the "doc" ZIP.
*
* @author <[email protected]>
* @version $Id: Syslog.java,v 1.23 2011/01/23 20:49:12 cvs Exp $
*/
public final class Syslog
{
protected static final Map instances = Maps.newHashMap();
/**
* Set up the default TCP and UDP Syslog protocols, as
* well as UNIX_SYSLOG and UNIX_SOCKET (if running on a Unix-based system).
*/
static {
initialize();
}
/**
* Syslog is a singleton.
*/
private Syslog() {
//
}
/**
* Use getInstance(protocol) as the starting point for Syslog4j.
*
* @param protocol - the Syslog protocol to use, e.g. "udp", "tcp", "unix_syslog", "unix_socket", or a custom protocol
* @return Returns an instance of SyslogIF.
* @throws SyslogRuntimeException
*/
public static SyslogIF getInstance(String protocol) throws SyslogRuntimeException {
String _protocol = protocol.toLowerCase();
if (instances.containsKey(_protocol)) {
return instances.get(_protocol);
} else {
StringBuffer message = new StringBuffer("Syslog protocol \"" + protocol + "\" not defined; call Syslogger.createSyslogInstance(protocol,config) first");
if (instances.size() > 0) {
message.append(" or use one of the following instances: ");
Iterator i = instances.keySet().iterator();
while (i.hasNext()) {
String k = (String) i.next();
message.append(k);
if (i.hasNext()) {
message.append(' ');
}
}
}
throw new SyslogRuntimeException(message.toString());
}
}
/**
* Use createInstance(protocol,config) to create your own Syslog instance.
*
* First, create an implementation of SyslogConfigIF, such as UdpNetSyslogConfig.
*
* Second, configure that configuration instance.
*
* Third, call createInstance(protocol,config) using a short & simple
* String for the protocol argument.
*
* Fourth, either use the returned instance of SyslogIF, or in later code
* call getInstance(protocol) with the protocol chosen in the previous step.
*
* @param protocol
* @param config
* @return Returns an instance of SyslogIF.
* @throws SyslogRuntimeException
*/
public static SyslogIF createInstance(String protocol, SyslogConfigIF config) throws SyslogRuntimeException
{
Preconditions.checkArgument(!StringUtils.isBlank(protocol), "Instance protocol cannot be null or empty");
Preconditions.checkArgument(config != null, "SyslogConfig cannot be null");
String syslogProtocol = protocol.toLowerCase();
SyslogIF syslog = null;
synchronized(instances) {
Preconditions.checkState(!instances.containsKey(syslogProtocol), "Syslog protocol \"%s\" already defined", protocol);
try {
Class syslogClass = config.getSyslogClass();
syslog = syslogClass.newInstance();
} catch (ClassCastException cse) {
if (!config.isThrowExceptionOnInitialize()) {
throw new SyslogRuntimeException(cse);
} else {
return null;
}
} catch (IllegalAccessException iae) {
if (!config.isThrowExceptionOnInitialize()) {
throw new SyslogRuntimeException(iae);
} else {
return null;
}
} catch (InstantiationException ie) {
if (!config.isThrowExceptionOnInitialize()) {
throw new SyslogRuntimeException(ie);
} else {
return null;
}
}
syslog.initialize(syslogProtocol,config);
instances.put(syslogProtocol,syslog);
}
return syslog;
}
/**
* @param protocol - Syslog protocol
* @return Returns whether the protocol has been previously defined.
*/
public static boolean exists(String protocol) {
if (StringUtils.isBlank(protocol)) {
return false;
}
return instances.containsKey(protocol.toLowerCase());
}
/**
* shutdown() gracefully shuts down all defined Syslog protocols,
* which includes flushing all queues and connections and finally
* clearing all instances (including those initialized by default).
*/
public synchronized static void shutdown() {
Set protocols = instances.keySet();
if (protocols.size() > 0) {
Iterator i = protocols.iterator();
SyslogUtility.sleep(SyslogConstants.THREAD_LOOP_INTERVAL_DEFAULT);
while(i.hasNext()) {
String protocol = i.next();
SyslogIF syslog = instances.get(protocol);
syslog.shutdown();
}
instances.clear();
}
}
private synchronized static void initialize() {
createInstance(SyslogConstants.UDP,new UDPNetSyslogConfig());
createInstance(SyslogConstants.TCP,new TCPNetSyslogConfig());
if (OSDetectUtility.isUnix() && SyslogUtility.isClassExists(SyslogConstants.JNA_NATIVE_CLASS)) {
createInstance(SyslogConstants.UNIX_SYSLOG,new UnixSyslogConfig());
createInstance(SyslogConstants.UNIX_SOCKET,new UnixSocketSyslogConfig());
}
}
static void reset() throws InterruptedException
{
shutdown();
Thread.sleep(200L);
initialize();
}
/**
* destroyInstance() gracefully shuts down the specified Syslog protocol and
* removes the instance from Syslog4j.
*
* @param protocol - the Syslog protocol to destroy
* @throws SyslogRuntimeException
*/
public synchronized static void destroyInstance(String protocol) throws SyslogRuntimeException {
if (StringUtils.isBlank(protocol)) {
return;
}
String _protocol = protocol.toLowerCase();
if (instances.containsKey(_protocol)) {
SyslogUtility.sleep(SyslogConstants.THREAD_LOOP_INTERVAL_DEFAULT);
SyslogIF syslog = instances.get(_protocol);
try {
syslog.shutdown();
} finally {
instances.remove(_protocol);
}
} else {
throw new SyslogRuntimeException("Cannot destroy protocol \"%s\" instance; call shutdown instead", protocol);
}
}
/**
* destroyInstance() gracefully shuts down the specified Syslog instance and
* removes it from Syslog4j.
*
* @param syslog - the Syslog instance to destroy
* @throws SyslogRuntimeException
*/
public synchronized static void destroyInstance(SyslogIF syslog) throws SyslogRuntimeException {
if (syslog == null) {
return;
}
String protocol = syslog.getProtocol().toLowerCase();
if (instances.containsKey(protocol)) {
try {
syslog.shutdown();
} finally {
instances.remove(protocol);
}
} else {
throw new SyslogRuntimeException("Cannot destroy protocol \"%s\" instance; call shutdown instead", protocol);
}
}
public static void main(String[] args) throws Exception {
SyslogMain.main(args);
}
}