Creates an instance of {@code PathHolder} initialized with the directory
location for storage of temporary files and common file name prefix for these
files.
if (dirLocation == null) {
throw new NullPointerException("dirLocation == null");
}
if (fileNamePrefix == null) {
throw new NullPointerException("fileNamePrefix == null");
}
this.dirLocation = dirLocation;
this.fileNamePrefix = fileNamePrefix;