ValueAccessor and PropertyMap changes

[navibyte]

Changes on ValueAccessor:

• moved to package:attributes/values.dart
• not implementing Counted any more
  • Some value accessors might not have size of values contained.
• renamed accessor bool existsNull(K key);, was previously hasNull
  • Returns true if a value with key exists and that value is null.
• new accessor bool existsNonNull(K key);
  • Returns true if a value with key exists and that value is non-null.
• new accessor num getNum(K key, {num? min, num? max});
  • Returns a value of num type at key.
  • Still getInt and getDouble properties available too.
  • Use getNum when accessor might have either int or double property value.
• new accessor num? tryNum(K key, {num? min, num? max});
  • similar as previous
  • but this returns null if if an underlying value is unavailable or cannot be converted to num.
• changed accessor DateTime getTimeUTC(K key, {DateTime Function(Object?)? parse});
  • new parameter parse to define app specific conversion.
• changed accessor DateTime? tryTimeUTC(K key, {DateTime Function(Object?)? parse});
  • new parameter parse to define app specific conversion.

Changes on ValueAccessorMixin

• moved to package:attributes/values.dart
• provides now default implementations only to accessor with "try" prefix
• those now check for Exception not only FormatException

Example of ValueAccessorMixin method:

  @override
  String? tryString(K key) {
    try {
      return getString(key);
    } on Exception {
      return null;
    }
  }

New base interface for property collections (maps and lists)

abstract class Properties<K> extends ValueAccessor<K> implements Counted {
  PropertyMap getMap(K key);
  PropertyMap? tryMap(K key);
  PropertyList getList(K key);
  PropertyList? tryList(K key);
}

Changes on PropertyMap:

• not anymore implementing ValueAccessor<String> directly
• but via extending Properties<String>
• removed factory PropertyMap.from(Map<String, dynamic> source)
• new factory PropertyMap.decodeJson(String data)

Also new PropertyList that extends Properties<int>

[navibyte]

Implemented on BETA-version 0.6.0.