public Attributes put(String key, String value) {
        int i = indexOfKey(key);
        if (i != NotFound)
            vals[i] = value;
        else
            add(key, value);
        return this;
    }
public Attributes put ( String key , String value ) { int i = indexOfKey ( key ) ; if ( i != NotFound ) vals [ i ] = value ; else add ( key , value ) ; return this ; }
Set a new attribute, or replace an existing one by key.
@param key case sensitive attribute key
@param value attribute value
@return these attributes, for chaining