* Gets the set of user-specified {@code Node.java} files. If none are found, {@code jjtree}
* will generate automatically a default one. This method search only in the package defined
* in the {@link #nodePackage} attribute.
*/
private Set searchNodeFiles() throws MojoExecutionException {
final SuffixMapping mapping = new SuffixMapping(".java", ".java");
final SuffixMapping mappingCAP = new SuffixMapping(".JAVA", ".JAVA");
final SourceInclusionScanner scanner = new StaleSourceScanner(staleMillis);
scanner.addSourceMapping(mapping);
scanner.addSourceMapping(mappingCAP);
File directory = new File(nodeDirectory);
if (nodePackage!=null && nodePackage.trim().length()!=0) {