dap4/d4lib/src/main/java/dap4/dap4lib/XURI.java
static public String
    canonical(String s)
    {
        if(s != null) {
            s = s.trim();
            if(s.length() == 0)
                s = null;
        }
        return s;
    }
static public String
    canonical(String s)
    {
        if(s != null) {
            s = s.trim();
            if(s.length() == 0)
                s = null;
        }
        return s;
    }
Canonicalize a part of a URL

@param s part of the url