The fourth programming project involves writing a program that accepts information contained in a file about the class dependencies in a Java program and creates a directed graph from that information. From the directed graph, it produces two different kinds of displays of those dependency relationships. A sample input file is shown below:

ClassA ClassC ClassE ClassJ ClassB ClassD ClassG ClassA ClassC ClassE ClassB ClassF ClassH ClassJ ClassB ClassI ClassC

The first name of each line of the file is a Java class upon which other classes depend. The remaining names are the classes that depend upon the first class on that line. The first line of the above file, for example, indicates that ClassA has three classes that depend upon it, ClassC, ClassE and ClassJ. A class that have does any classes that depend on it, need not appear at the head of any line. The main method in the class for this project should allow user select the input file from the default directory by using the JFileChooser class. It should then add the edges to a directed graph that defines these class dependencies. A second class, DirectedGraph, should be a generic class, whose generic parameter specifies the type of the labels that are associated with the vertices of the graph. It should contain a method that allows edges to be added to the graph, which is how the main method will initially build the graph. It should also contain a method that performs a depth-first search of that graph. The pseudocode for that search is show below: depth_first_search(vertex s) if s is discovered perform cycle detected action return perform add vertex action mark s as discovered perform descend action for all adjacent vertices v depth_first_search(v) perform ascend action mark s as finished When the method in the DirectedGraph class that initiates the depth first search is called, it should first initialize all the vertices to the undiscovered state and begin the search at the vertex that corresponds to the first name in the input file. Another method in the DirectedGraph class should then allow the main method to display any unreachable classes by examining all the vertices of the graph to see which remain undiscovered. This project should contain a generic interface named DFSActions, whose generic parameter again specifies the type of the labels that are associated with the vertices of the graph. It should contain four method signatures that correspond to the four actions performed in the depth first search: cycle detected, process vertex, descend and ascend. There should be two additional classes that both implement the aforementioned interface. The first, Hierarchy, should produce a hierarchical representation of the class dependencies. Circular dependencies should be flagged. For the above input file, the following hierarchical representation should be produced:

ClassA

ClassC *

ClassB

ClassD

ClassG

ClassF

ClassH

ClassE

ClassJ

ClassB

ClassD

ClassG

The asterisk after ClassC results from the fact that ClassC depends upon ClassA and ClassA depends upon ClassC. The Hierarchy class should override the toString method, which should return a string that contains the above, after having performed the depth-first search. The other class that implements the DFSActions interface should be ParenthesizedList. It should produce an alternate representation that is also returned by its toString method. For the above input file, the following hierarchical representation should be produced:

( ClassA ( ClassC * ClassE ( ClassB ( ClassD ClassG ) ClassF ClassH ) ClassJ ( ClassB ( ClassD ClassG ))))

The main method should produce both representations. In addition it should display the unreachable classes by calling the previously mentioned method. For the above input file, the following unreachable class should be identified: ClassI is unreachable Code duplication should be avoided. In particular, the depth first code should not be duplicated.