* If a file cannot be read, errorHandler will be notified.
*/
public void addSourceTree(File file, final FileVisitor errorHandler) {
DirectoryScanner scanner = new DirectoryScanner(file);
scanner.addFilter(new SuffixFilter(".java"));
scanner.scan(new FileVisitor() {
public void visitFile(File currentFile) {
try {
addSource(currentFile);
} catch (IOException e) {
errorHandler.visitFile(currentFile);