Thomas Hammell

The ability to transfer information by dragging data from one component to another has been around since the development of the graphical user interface. Over the years drag-and-drop has gone from a cool feature to a required piece of most user interfaces. Most users expect to be able to drag objects between fields, windows, or folders and have some action occur. Drag-and-drop is even used to open applications by dragging a file to an application icon. For a Java developer creating user interfaces it's no longer a question of whether drag-and-drop should be used but of how much. Java provides a set of classes for implementing the drag-and-drop interface. While it's not overly complex, implementing it in a complex GUI with a number of drag sources and drop targets can be tedious and error-prone. In this article, I develop an abstract DnDHandler class that takes care... (more)

Test First, Code Later

Testing is usually an afterthought in the development process. The developer's main focus is to design and write code. Of course, the developer runs the program many times during development to make sure the code runs and produces the expected results; however, this testing has no real structure and the main goal is to ensure the program runs at that moment. Most developers rely too much on QA or the end user to make sure the program works properly and meets requirements. Extreme Programming has taken the "build a little, test a little" philosophy to a new level by requiring that... (more)