After pressing the Build Directed Graph button, one of following two messages should be generated depending upon whether the specified file name...

After pressing the Build Directed Graph button, one of following two messages should be generated depending upon whether the specified file name could be opened:

Once the graph has been built, the name of a class to be recompiled can be specified and the Topological Order button can be pressed. Provided a valid class name has been supplied, the list of classes that need to be recompiled should be listed in the order they are to be recompiled in the text area at the bottom of the window. An invalid class name should generate an appropriate error message.

The correct recompilation order is any topological order of the subgraph that emanates from the specified vertex. Topological orders are not unique, but the one that is to be used for this program is the one generated using a depth-first search of the graph. The algorithm for generating this topological order is shown below: