May I suggest to add this method to the org.apache.fop.hyphenation.Hyphenator class? I had to hack FOP and create a custom build for myself, because I need to reload the hyphenation files at runtime. The use case is, that I have a web applications that allows on an admin page, to add hyphenation exceptions on-the-fly. In that case the hyphenation pattern files are re-created with the new exceptions but need to be reloaded by FOP. The below worked for me, please consider adding to the trunk.
Best, Marc /** * Clear the hyphenation tree cache, in case the underlying data files have changed at runtime. */ public static synchronized void clearHyphenationTreeCache() { hTreeCache = new HyphenationTreeCache(); }