Replacement pattern for an anonymous class in Dart -

i'm trying build base class table< t > uses list tablecolumns< t > display table in dart. in java done anonymous class pattern leaf class simple following:

class parttable extends table< part > {    // column 1: part number     addcolumn( new tablecolumn<part>("part number") {      string get(part part) { part.getnumber().tostring() }      void set(part part, string number) {       part.setnumber(number);     }   });    // column 2: part description    addcolumn( new tablecolumn<part>("part description") {      string get(part part) { part.getdescription().tostring() }      void set(part part, string desc) {       part.setdescription(desc);     }   });  } 

can suggest dart design pattern nicely substitute java anonymous class pattern above? basic idea anonymous tablecolumn class abstract methods (e.g. , set) overridden by anonymous class in table constructor provide view specific overrides working part's attributes. table can have arbitrary number of columns, , provide view specific crud behavior each parts attributes in tables cell.

i don't think there's general answer question. depends on code. can ever create class anonymous class or refactor api , try avoid them.

for instance sample code refactored use functions define get/set :

final table = new table<part>()     ..addcolumn(new column<part>(         "part number",          (p) => p.number.tostring(),         (p, s) => p.number = s))     ..addcolumn(new column<part>(         "part description",          (p) => p.desc.tostring(),          (p, s) => p.desc = s)); 

here's underlying code :

typedef string columngetter<t>(t t);  typedef void columnsetter<t>(t t, string s);  class column<t> {   final string name;   final columngetter<t> get;   final columnsetter<t> set;   column(this.name, this.get, this.set); }  class table<t> {   list<t> _elements;   final _columns = [];   void addcolumn(column<t> column) => _columns.add(column);   void set elements(list<t> elements) {     this._elements = elements;     // updatedisplay   } }