Objective: to develop a Java program to perform the pre-processing step of a text to be analyzed as a digraph by the free software tool Gephi. The program should accept a list of filenames of the plain text type (.txt) and, for each of them, record an output in .csv format containing lists of adjacencies indicating succession of words for later construction of digraphs, as described below :
each word is a unique node of the digraph (beginning of an adjacency list);
node A has an arc for node B if and only if the word represented by B follows that represented by A in the text;
each line of the output file starts with the word that represents the origin node, followed by the words that are the destinations of the arcs that start from it, separated by spaces or commas (Gephi format).