Gaeds 1.2 Changes #2 - Converters

Gaeds is my tiny AppEngine for Java low-level DatastoreService wrapper. This is second post in three post series about new features that will form 1.2 final release.

Since first release of gaeds it has Model property value conversion support from-to Entity properties using Converter. There are few default converters and its easy to write additional ones. To declare that property needs converter, @Property annotation has type setting:

@Model
public class Something {

  @Property(type = Text.class)
  private String text;

}

For Something.text property before creating or updating Entity Converter<String, Text> will kick in and convert String value to Text and after get or query operations, the same converter will convert Text back to String and set it to model property.

But now lets consider the following property:

@Model
public class Something {

  @Property(field = Serializable.class, type = Blob.class)
  private Map<String, Integer> paymentDetails;

}

The Converter lookup is done using newly added @Property.field, if it is not provided, using actual field type. Because in this example @Property.field is set, the Converter<Serializable, Blob> is used instead of Converter<Map, Blob>.

Also see Gaeds 1.2-SNAPSHOT Changes #2 — Converters to learn about changes in Converter configuration.