Commons IO - Home. Commons Chain - Overview. Commons Chain A popular technique for organizing the execution of complex processing flows is the "Chain of Responsibility" pattern, as described (among many other places) in the classic "Gang of Four" design patterns book.
Although the fundamental API contracts required to implement this design patten are extremely simple, it is useful to have a base API that facilitates using the pattern, and (more importantly) encouraging composition of command implementations from multiple diverse sources. Towards that end, the Chain API models a computation as a series of "commands" that can be combined into a "chain". Commons Chain - Cookbook. Introduction The essence of computing might be that for any expected input (A), we return the expected output (B). The challenge is getting from (A) to (B). For a simple program, (A) to (B) might be a single transformation. Struts. Key Technologies Primer. "The time has come," the Walrus said, "To talk of many things: Of shoes -- and ships -- and sealing-wax -- Of cabbages -- and kings -- And why the sea is boiling hot -- And whether pigs have wings.
" Intention If you would like to get started with Apache Struts you most likely want to know what technologies you need to learn. This document shall give you a brief overview what you need to successfully run a Struts project. Apache log4j 1.2 - Short introduction to log4j. Log4j has three main components: loggers, appenders and layouts.
These three types of components work together to enable developers to log messages according to message type and level, and to control at runtime how these messages are formatted and where they are reported. Logger hierarchy The first and foremost advantage of any logging API over plain System.out.println resides in its ability to disable certain log statements while allowing others to print unhindered. PatternLayout (Apache Log4j 1.2.16 API) Java.lang.Object org.apache.log4j.Layout org.apache.log4j.PatternLayout All Implemented Interfaces: