]> Contents Logging Logging LookupDiscovery This chapter deals with the logging API, which is used by Jini 2. This can be used for auditing or debugging. Jini 2.0 introduced use of the java.util.logging package. This can be used for auditing, or possibly for debugging. The logging package allows an application to write to named logs. Typically the name of a log is a package name. For example, the log for LookupDiscovery objects is "net.jini.discovery.LookupDiscovery". Each object will write a record of its activities to the class log. These messages will have levels such as SEVERE, INFO, etc, down to FINEST. For example, LookupDiscovery objects will write these messages, among others: SEVERE if a network interface is bad or not configured for multicast INFO when any exception other than an InterruptedIOException occurs while attempting unicast discovery FINEST whenever a discovered, discarded, or changed event is sent In order to see what is put into a log, a Handler must be added to the log. There are several supplied handlers, including: ConsoleHandler. This handler writes all log messages to the console that have INFO level or above. The format is given by the SimpleFormatter object, and just gives brief readable messages FileHandler. This handler writes all messages to a file, using an XML format. If you only want simple messages, this can be set to be a SimpleFormatter A program to log activities of a LookupDiscovery object is given by this program, which just adds logging to the earlier MulticastRegister program When this is run, a few messages will be printed to the console. A great deal more will be written to the mylog.txt file, including a line like FINEST: discovered locator = jini://jannote.jan.edu.au/ whenever a lookup locator is found. ©right;