Interface TypePlugin

All Superinterfaces:
Proxy
All Known Implementing Classes:
IOModule, TypeModule, TypeModule.TypeModule$Impl, TypePlugin.TypePlugin$Impl
@Generated("org.javagi.JavaGI") public interface TypePlugin extends Proxy

An interface that handles the lifecycle of dynamically loaded types.

The GObject type system supports dynamic loading of types. It goes as follows:

  1. The type is initially introduced (usually upon loading the module the first time, or by your main application that knows what modules introduces what types), like this:

    new_type_id = g_type_register_dynamic (parent_type_id,
                                       "TypeName",
                                       new_type_plugin,
                                       type_flags);

    where new_type_plugin is an implementation of the GTypePlugin interface.

  2. The type's implementation is referenced, e.g. through TypeClass.ref(Type) or through GObjects.typeCreateInstance(Type) (this is being called by GObject()) or through one of the above done on a type derived from new_type_id.

  3. This causes the type system to load the type's implementation by calling use() and completeTypeInfo(Type, TypeInfo, TypeValueTable) on new_type_plugin.

  4. At some point the type's implementation isn't required anymore, e.g. after TypeClass.unref() or GObjects.typeFreeInstance(TypeInstance) (called when the reference count of an instance drops to zero).

  5. This causes the type system to throw away the information retrieved from completeTypeInfo(Type, TypeInfo, TypeValueTable) and then it calls unuse() on new_type_plugin.

  6. Things may repeat from the second step.

So basically, you need to implement a GTypePlugin type that carries a use_count, once use_count goes from zero to one, you need to load the implementation to successfully handle the upcoming completeTypeInfo(Type, TypeInfo, TypeValueTable) call. Later, maybe after succeeding use/unuse calls, once use_count drops to zero, you can unload the implementation again. The type system makes sure to call use() and completeTypeInfo(Type, TypeInfo, TypeValueTable) again when the type is needed again.

TypeModule is an implementation of GTypePlugin that already implements most of this except for the actual module loading and unloading. It even handles multiple registered types per module.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static class 
    TypePlugin.TypePlugin$Impl
    The TypePlugin$Impl type represents a native instance of the TypePlugin interface.

  • Method Summary

    Modifier and Type
    Method
    Description
    default void
    completeInterfaceInfo(Type instanceType, Type interfaceType, InterfaceInfo info)
    Calls the completeInterfaceInfo function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.
    default void
    completeTypeInfo(Type gType, TypeInfo info, TypeValueTable valueTable)
    Calls the completeTypeInfo function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.
    static @Nullable Type
    getType()
    Get the GType of the TypePlugin class.
    default void
    unuse()
    Calls the unusePlugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.
    default void
    use()
    Calls the usePlugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.

    Methods inherited from interface Proxy

    handle

  • Method Details

    • getType

      static @Nullable Type getType()
      Get the GType of the TypePlugin class.
      Returns:
      the GType

    • completeInterfaceInfo

      default void completeInterfaceInfo(Type instanceType, Type interfaceType, InterfaceInfo info)
      Calls the completeInterfaceInfo function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.
      Parameters:
      instanceType - the GType of an instantiatable type to which the interface is added
      interfaceType - the GType of the interface whose info is completed
      info - the GInterfaceInfo to fill in

    • completeTypeInfo

      default void completeTypeInfo(Type gType, TypeInfo info, TypeValueTable valueTable)
      Calls the completeTypeInfo function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.
      Parameters:
      gType - the GType whose info is completed
      info - the GTypeInfo struct to fill in
      valueTable - the GTypeValueTable to fill in

    • unuse

      default void unuse()
      Calls the unusePlugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.

    • use

      default void use()
      Calls the usePlugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.