This FileHandler allows to analyze WebServer log files in the Apache common or combined format.
It provides a way to scan a directory for updated and new log files and will load the information therein into a compacted representation in memory.
After loading the data can be filtered for display using an XML file containing the filter criteria. (Such a filter can also be used to limit the entries which get loaded into memory).
Based on that information, various reports can be viewed which aggregate the statistics in the most interesting areas. Within these reports it is possible to select the interesting parts from the overall log entry table. This allows to understand the corresponding client requests in their context.
A refresh algorithm will check for updated log files on disk and will only reload those parts that are necessary, thus reducing analyzing overhead to a minimum.
If the log files only contain IP addresses of the requesting clients, the viewer supports a small side-file with the necessary DNS lookup table. If a file with the same name as the log file and an additional suffix of .dns is found, it will be read and interpreted in the following way:
Each line represents a mapping from an IP address to a DNS host name (a.k.a. a reverse DNS lookup mapping). Such a line starts with the IP address, followed by a colon and then the host name.