Class UDPAppender

  • All Implemented Interfaces:
    org.apache.log4j.Appender, NetworkBased, PortBased, org.apache.log4j.spi.OptionHandler

    public class UDPAppender
    extends org.apache.log4j.AppenderSkeleton
    implements PortBased
    Sends log information as a UDP datagrams.

    The UDPAppender is meant to be used as a diagnostic logging tool so that logging can be monitored by a simple UDP client.

    Messages are not sent as LoggingEvent objects but as text after applying the designated Layout.

    The port and remoteHost properties can be set in configuration properties. By setting the remoteHost to a broadcast address any number of clients can listen for log messages.

    This was inspired and really extended/copied from SocketAppender. Please see the docs for the proper credit to the authors of that class.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) java.net.InetAddress address  
      private boolean advertiseViaMulticastDNS  
      (package private) java.lang.String application  
      static int DEFAULT_PORT
      The default port number for the UDP packets, 9991.
      (package private) java.lang.String encoding  
      (package private) java.lang.String hostname
      We remember host name as String in addition to the resolved InetAddress so that it can be returned via getOption().
      (package private) boolean inError  
      (package private) java.net.DatagramSocket outSocket  
      (package private) int port  
      (package private) java.lang.String remoteHost  
      private org.apache.log4j.net.ZeroConfSupport zeroConf  
      static java.lang.String ZONE
      The MulticastDNS zone advertised by a UDPAppender
      • Fields inherited from class org.apache.log4j.AppenderSkeleton

        closed, errorHandler, headFilter, layout, name, tailFilter, threshold
    • Constructor Summary

      Constructors 
      Constructor Description
      UDPAppender()  
      UDPAppender​(java.lang.String host, int port)
      Sends UDP packets to the address and port.
      UDPAppender​(java.net.InetAddress address, int port)
      Sends UDP packets to the address and port.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void activateOptions()
      Open the UDP sender for the RemoteHost and Port.
      void append​(org.apache.log4j.spi.LoggingEvent event)  
      void cleanUp()
      Close the UDP Socket and release the underlying connector thread if it has been created
      void close()
      Close this appender.
      (package private) void connect​(java.net.InetAddress address, int port)  
      (package private) java.net.InetAddress getAddressByName​(java.lang.String host)  
      java.lang.String getApplication()
      Returns value of the App option.
      java.lang.String getEncoding()
      Returns value of the Encoding option.
      int getPort()
      Returns value of the Port option.
      java.lang.String getRemoteHost()
      Returns value of the RemoteHost option.
      boolean isActive()
      Get if item is active.
      boolean isAdvertiseViaMulticastDNS()  
      boolean requiresLayout()
      The UDPAppender uses layouts.
      void setAdvertiseViaMulticastDNS​(boolean advertiseViaMulticastDNS)  
      void setApplication​(java.lang.String app)
      The App option takes a string value which should be the name of the application getting logged.
      void setEncoding​(java.lang.String encoding)
      The Encoding option specifies how the bytes are encoded.
      void setPort​(int port)
      The Port option takes a positive integer representing the port where UDP packets will be sent.
      void setRemoteHost​(java.lang.String host)
      The RemoteHost option takes a string value which should be the host name or ipaddress to send the UDP packets.
      • Methods inherited from class org.apache.log4j.AppenderSkeleton

        addFilter, clearFilters, doAppend, finalize, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setErrorHandler, setLayout, setName, setThreshold
      • Methods inherited from class java.lang.Object

        clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • DEFAULT_PORT

        public static final int DEFAULT_PORT
        The default port number for the UDP packets, 9991.
        See Also:
        Constant Field Values
      • hostname

        java.lang.String hostname
        We remember host name as String in addition to the resolved InetAddress so that it can be returned via getOption().
      • remoteHost

        java.lang.String remoteHost
      • application

        java.lang.String application
      • encoding

        java.lang.String encoding
      • address

        java.net.InetAddress address
      • port

        int port
      • outSocket

        java.net.DatagramSocket outSocket
      • ZONE

        public static final java.lang.String ZONE
        The MulticastDNS zone advertised by a UDPAppender
        See Also:
        Constant Field Values
      • inError

        boolean inError
      • advertiseViaMulticastDNS

        private boolean advertiseViaMulticastDNS
      • zeroConf

        private org.apache.log4j.net.ZeroConfSupport zeroConf
    • Constructor Detail

      • UDPAppender

        public UDPAppender()
      • UDPAppender

        public UDPAppender​(java.net.InetAddress address,
                           int port)
        Sends UDP packets to the address and port.
      • UDPAppender

        public UDPAppender​(java.lang.String host,
                           int port)
        Sends UDP packets to the address and port.
    • Method Detail

      • activateOptions

        public void activateOptions()
        Open the UDP sender for the RemoteHost and Port.
        Specified by:
        activateOptions in interface org.apache.log4j.spi.OptionHandler
        Overrides:
        activateOptions in class org.apache.log4j.AppenderSkeleton
      • close

        public void close()
        Close this appender.

        This will mark the appender as closed and call then cleanUp() method.

        Specified by:
        close in interface org.apache.log4j.Appender
      • cleanUp

        public void cleanUp()
        Close the UDP Socket and release the underlying connector thread if it has been created
      • connect

        void connect​(java.net.InetAddress address,
                     int port)
      • append

        public void append​(org.apache.log4j.spi.LoggingEvent event)
        Specified by:
        append in class org.apache.log4j.AppenderSkeleton
      • isActive

        public boolean isActive()
        Description copied from interface: NetworkBased
        Get if item is active.
        Specified by:
        isActive in interface NetworkBased
        Returns:
        if true, item is active.
      • getAddressByName

        java.net.InetAddress getAddressByName​(java.lang.String host)
      • requiresLayout

        public boolean requiresLayout()
        The UDPAppender uses layouts. Hence, this method returns true.
        Specified by:
        requiresLayout in interface org.apache.log4j.Appender
      • setRemoteHost

        public void setRemoteHost​(java.lang.String host)
        The RemoteHost option takes a string value which should be the host name or ipaddress to send the UDP packets.
      • getRemoteHost

        public java.lang.String getRemoteHost()
        Returns value of the RemoteHost option.
      • setApplication

        public void setApplication​(java.lang.String app)
        The App option takes a string value which should be the name of the application getting logged. If property was already set (via system property), don't set here.
      • getApplication

        public java.lang.String getApplication()
        Returns value of the App option.
      • setEncoding

        public void setEncoding​(java.lang.String encoding)
        The Encoding option specifies how the bytes are encoded. If this option is not specified, the System encoding is used.
      • getEncoding

        public java.lang.String getEncoding()
        Returns value of the Encoding option.
      • setPort

        public void setPort​(int port)
        The Port option takes a positive integer representing the port where UDP packets will be sent.
      • getPort

        public int getPort()
        Returns value of the Port option.
        Specified by:
        getPort in interface PortBased
        Returns:
        int port number
      • setAdvertiseViaMulticastDNS

        public void setAdvertiseViaMulticastDNS​(boolean advertiseViaMulticastDNS)
      • isAdvertiseViaMulticastDNS

        public boolean isAdvertiseViaMulticastDNS()