README.txt
1 There are two libraries defined in this directory:
2 First, com.android.media.remotedisplay.jar is a shared java library
3 containing classes required by unbundled remote display providers.
4 Second, com.android.media.remotedisplay.stubs.jar is a stub for the shared
5 library which provides build-time APIs to the unbundled clients.
6
7 At runtime, the shared library is added to the classloader of the app via the
8 <uses-library> tag. And since Java always tries to load a class from the
9 parent classloader, regardless of whether the stub library is linked to the
10 app statically or dynamically, the real classes are loaded from the shared
11 library.
12
13 --- Rules of this library ---
14 o The stub library is effectively a PUBLIC API for unbundled remote display providers
15 that may be distributed outside the system image. So it MUST BE API STABLE.
16 You can add but not remove. The rules are the same as for the
17 public platform SDK API.
18 o This library can see and instantiate internal platform classes, but it must not
19 expose them in any public method (or by extending them via inheritance). This would
20 break clients of the library because they cannot see the internal platform classes.
21
22 This library is distributed in the system image, and loaded as
23 a shared library. So you can change the implementation, but not
24 the interface. In this way it is like framework.jar.
25
26 --- Why does this library exists? ---
27
28 Unbundled remote display providers (such as Cast) cannot use internal
29 platform classes.
30
31 This library will eventually be replaced when the media route provider
32 infrastructure that is currently defined in the support library is reintegrated
33 with the framework in a new API. That API isn't ready yet so this
34 library is a compromise to make new capabilities available to the system
35 without exposing the full surface area of the support library media
36 route provider protocol.
37