ExtensionPool pool = getUserExtensionPool();
    public void commit(IRequestCycle cycle_) {        // Proceed only if Tapestry validation succeeded        if (!TapestryUtils.isValid(this)) {            return;        }                // For now, we are not letting the user edit the pool's nextExtension value,        // which controls where to start looking for the next free extension.        // Set it to be the same as the start of the range.        ExtensionPool pool = getUserExtensionPool();        pool.setNextExtension(pool.getFirstExtension());                getExtensionPoolContext().saveExtensionPool(pool);    }