Package ch.bailu.gtk.gio

Class AsyncInitable

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.type.Interface
ch.bailu.gtk.gio.AsyncInitable
All Implemented Interfaces:
PointerInterface
public class AsyncInitable extends Interface
This is the asynchronous version of #GInitable; it behaves the same
in all ways except that initialization is asynchronous. For more details
see the descriptions on #GInitable.

A class may implement both the #GInitable and #GAsyncInitable interfaces.

Users of objects implementing this are not intended to use the interface
method directly; instead it will be used automatically in various ways.
For C applications you generally just call g_async_initable_new_async()
directly, or indirectly via a foo_thing_new_async() wrapper. This will call
g_async_initable_init_async() under the cover, calling back with %NULL and
a set %GError on failure.

A typical implementation might look something like this: 
<!-- language="C" -->
 enum {
    NOT_INITIALIZED,
    INITIALIZING,
    INITIALIZED
 };
 
 static void
 _foo_ready_cb (Foo *self)
 {
   GList *l;
 
   self->priv->state = INITIALIZED;
 
   for (l = self->priv->init_results; l != NULL; l = l->next)
     {
       GTask *task = l->data;
 
       if (self->priv->success)
         g_task_return_boolean (task, TRUE);
       else
         g_task_return_new_error (task, ...);
       g_object_unref (task);
     }
 
   g_list_free (self->priv->init_results);
   self->priv->init_results = NULL;
 }
 
 static void
 foo_init_async (GAsyncInitable       *initable,
                 int                   io_priority,
                 GCancellable         *cancellable,
                 GAsyncReadyCallback   callback,
                 gpointer              user_data)
 {
   Foo *self = FOO (initable);
   GTask *task;
 
   task = g_task_new (initable, cancellable, callback, user_data);
   g_task_set_name (task, G_STRFUNC);
 
   switch (self->priv->state)
     {
       case NOT_INITIALIZED:
         _foo_get_ready (self);
         self->priv->init_results = g_list_append (self->priv->init_results,
                                                   task);
         self->priv->state = INITIALIZING;
         break;
       case INITIALIZING:
         self->priv->init_results = g_list_append (self->priv->init_results,
                                                   task);
         break;
       case INITIALIZED:
         if (!self->priv->success)
           g_task_return_new_error (task, ...);
         else
           g_task_return_boolean (task, TRUE);
         g_object_unref (task);
         break;
     }
 }
 
 static gboolean
 foo_init_finish (GAsyncInitable       *initable,
                  GAsyncResult         *result,
                  GError              **error)
 {
   g_return_val_if_fail (g_task_is_valid (result, initable), FALSE);
 
   return g_task_propagate_boolean (G_TASK (result), error);
 }
 
 static void
 foo_async_initable_iface_init (gpointer g_iface,
                                gpointer data)
 {
   GAsyncInitableIface *iface = g_iface;
 
   iface->init_async = foo_init_async;
   iface->init_finish = foo_init_finish;
 }

https://docs.gtk.org/gio/iface.AsyncInitable.html

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • initAsync

      public void initAsync(int io_priority, @Nullable Cancellable cancellable, AsyncInitable.OnAsyncReadyCallback callback, @Nullable Pointer user_data)
      Starts asynchronous initialization of the object implementing the
      interface. This must be done before any real use of the object after
      initial construction. If the object also implements #GInitable you can
      optionally call g_initable_init() instead.

      This method is intended for language bindings. If writing in C,
      g_async_initable_new_async() should typically be used instead.

      When the initialization is finished, @callback will be called. You can
      then call g_async_initable_init_finish() to get the result of the
      initialization.

      Implementations may also support cancellation. If @cancellable is not
      %NULL, then initialization can be cancelled by triggering the cancellable
      object from another thread. If the operation was cancelled, the error
      %G_IO_ERROR_CANCELLED will be returned. If @cancellable is not %NULL, and
      the object doesn't support cancellable initialization, the error
      %G_IO_ERROR_NOT_SUPPORTED will be returned.

      As with #GInitable, if the object is not initialized, or initialization
      returns with an error, then all operations on the object except
      g_object_ref() and g_object_unref() are considered to be invalid, and
      have undefined behaviour. They will often fail with g_critical() or
      g_warning(), but this must not be relied on.

      Callers should not assume that a class which implements #GAsyncInitable can
      be initialized multiple times; for more information, see g_initable_init().
      If a class explicitly supports being initialized multiple times,
      implementation requires yielding all subsequent calls to init_async() on the
      results of the first call.

      For classes that also support the #GInitable interface, the default
      implementation of this method will run the g_initable_init() function
      in a thread, so if you want to support asynchronous initialization via
      threads, just implement the #GAsyncInitable interface without overriding
      any interface methods.
      Parameters:
      io_priority - the [I/O priority][io-priority] of the operation
      cancellable - optional #GCancellable object, %NULL to ignore.
      callback - a #GAsyncReadyCallback to call when the request is satisfied
      user_data - the data to pass to callback function

    • initFinish

      public boolean initFinish(@Nonnull AsyncResult res) throws AllocationError
      Finishes asynchronous initialization and returns the result.
      See g_async_initable_init_async().
      Parameters:
      res - a #GAsyncResult.
      Returns:
      %TRUE if successful. If an error has occurred, this function will return %FALSE and set @error appropriately if present.
      Throws:
      AllocationError

    • newFinish

      public Object newFinish(@Nonnull AsyncResult res) throws AllocationError
      Finishes the async construction for the various g_async_initable_new
      calls, returning the created object or %NULL on error.
      Parameters:
      res - the #GAsyncResult from the callback
      Returns:
      a newly created #GObject, or %NULL on error. Free with g_object_unref().
      Throws:
      AllocationError

    • newAsync

      public static void newAsync(long object_type, int io_priority, @Nullable Cancellable cancellable, AsyncInitable.OnAsyncReadyCallback callback, @Nullable Pointer user_data, @Nullable Str first_property_name, Object... _elipse)
      Helper function for constructing #GAsyncInitable object. This is
      similar to g_object_new() but also initializes the object asynchronously.

      When the initialization is finished, @callback will be called. You can
      then call g_async_initable_new_finish() to get the new object and check
      for any errors.
      Parameters:
      object_type - a #GType supporting #GAsyncInitable.
      io_priority - the [I/O priority][io-priority] of the operation
      cancellable - optional #GCancellable object, %NULL to ignore.
      callback - a #GAsyncReadyCallback to call when the initialization is finished
      user_data - the data to pass to callback function
      first_property_name - the name of the first property, or %NULL if no properties
      _elipse - the value of the first property, followed by other property value pairs, and ended by %NULL.

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()