Problem with text field behaviour when content too long

I have a report where a text field has to be a fixed width. The current font and size holds 16 characters. If there are more in the data, that's ok. The problem is that Japser is truncating at the last space. I want it to truncate at character 16. I have tried setting property net.sf.jasperreports.print.keep.full.text but this doesn't work. What should I do to make sure it doesn't truncate at the last space?