Class Mappers

java.lang.Object
com.codename1.mapping.Mappers
public final class Mappers extends Object

Public entry point for the build-time JSON / XML mapping framework.

@Mapped classes get a generated mapper at build time. The generated mapper's static initializer self-registers with this registry. The registry stays empty until something triggers each generated class's <clinit>:

  • iOS / Android -- the build server probes the project zip for cn1app.MapperBootstrap, and when present splices a new cn1app.MapperBootstrap(); into the per-build application stub before Display.init. That constructor references every generated mapper, triggering their static initializers.
  • JavaSE simulator + desktop -- JavaSEPort#postInit calls Class.forName("cn1app.MapperBootstrap") so the registry is populated on the same boundary. Classloading is the legitimate path here: JavaSE runs unobfuscated.
  • Unit tests / manual init -- application code can call Mappers.register(...) directly to install a hand-written mapper for a class the build can't annotate.

Typical use after init:

String json = Mappers.toJson(user);
User u = Mappers.fromJson(json, User.class);

String xml = Mappers.toXml(user);
User u = Mappers.fromXml(xml, User.class);

The registry is keyed on getClass().getName() so it survives ParparVM rename and R8 obfuscation: both the registration site and the lookup site see the same renamed name within a single execution. The map keys are never persisted, so the renaming has no observable effect on behavior.

  • Method Details

    • register

      public static <T> void register(Mapper<T> mapper)
      Installs mapper under mapper.type().getName(). The generated per-class mapper's static initializer calls this; hand-written mappers for classes outside the build's annotation scan call it explicitly.

    • get

      public static <T> Mapper<T> get(Class<T> type)
      Looks up the mapper for type (by type.getName()) or null when none is registered.

    • toJson

      public static String toJson(Object instance)
      Serializes instance to JSON. Throws IllegalStateException when no mapper is registered for its concrete class; that always points at a missing @Mapped annotation or a build that ran without the process-annotations Mojo.

    • fromJson

      public static <T> T fromJson(String json, Class<T> type)
      Inverse of #toJson. Parses the JSON text and hands the resulting Map to the registered mapper.

    • fromJson

      public static <T> T fromJson(Reader json, Class<T> type)
      Parses JSON read from a Reader (file, network response, ...) without fully buffering it into a String first.

    • toXml

      public static String toXml(Object instance)
      Serializes instance to XML.

    • fromXml

      public static <T> T fromXml(String xml, Class<T> type)
      Inverse of #toXml. Parses the XML text and hands the resulting Element to the registered mapper.

    • fromXml

      public static <T> T fromXml(Reader xml, Class<T> type)
      Parses XML read from a Reader without fully buffering it first.