this.parser = parser;
this.nl = nl;
units = new HashMap<String, Unit>();
prefixes = new HashMap<String, BigDec>();
abbreviatedPrefixes = new HashMap<String, String>();
unitAbbreviations = new TreeMap<String, String>(new LengthComparison());
allUnits = new SortedList<String>(new LengthComparison());
//I know, but it is slightly faster than using an array and iterating through while converting to BigDec
prefixes.put("yocto", new BigDec(-8));
prefixes.put("zepto", new BigDec(-7));
prefixes.put("atto", new BigDec(-6));