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 Summary

    Modifier and Type
    Method
    Description
    static <T> T
    fromJson(java.io.Reader json, Class<T> type)
    Parses JSON read from a Reader (file, network response, ...) without fully buffering it into a String first.
    static <T> T
    fromJson(String json, Class<T> type)
    Inverse of #toJson.
    static <T> T
    fromXml(java.io.Reader xml, Class<T> type)
    Parses XML read from a Reader without fully buffering it first.
    static <T> T
    fromXml(String xml, Class<T> type)
    Inverse of #toXml.
    static <T> Mapper<T>
    get(Class<T> type)
    Looks up the mapper for type (by type.getName()) or null when none is registered.
    static <T> void
    register(Mapper<T> mapper)
    Installs mapper under mapper.type().getName().
    static String
    toJson(Object instance)
    Serializes instance to JSON.
    static String
    toXml(Object instance)
    Serializes instance to XML.

    Methods inherited from class Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • 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(java.io.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(java.io.Reader xml, Class<T> type)
      Parses XML read from a Reader without fully buffering it first.