PF4J : Async

PF4J doesn’t supply an Async API out of the box. I added a POC (Proof Of Concept) on the async branch. I updated demo (Boot class) to use the new Async API. Everything is functional.

I added below two code snippets (from demo/Boot.java) that show you the API used to load&start plugins using SYNC and ASYNC variant. In the new async API I added two new methods (until now) that end with Async:

loadPluginsAsync
startPluginsAsync

Load and start plugins sync

// create the plugin manager
final PluginManager pluginManager = new DefaultPluginManager();

// load the plugins
pluginManager.loadPlugins();

// start (active/resolved) the plugins
pluginManager.startPlugins();

// retrieves the extensions for Greeting extension point
List<Greeting> greetings = pluginManager.getExtensions(Greeting.class);

Load and start plugins async

// create the plugin manager
final AsyncPluginManager pluginManager = new DefaultAsyncPluginManager();

// load the plugins
CompletionStage<Void> stage = pluginManager.loadPluginsAsync();
stage.thenRun(() -> System.out.println("Plugins loaded")); // optional

// start (active/resolved) the plugins
stage.thenCompose(v -> pluginManager.startPluginsAsync());
stage.thenRun(() -> System.out.println("Plugins started")); // optional

// block and wait for the future to complete (not the best approach in real applications)
stage.toCompletableFuture().get();

// retrieves the extensions for Greeting extension point
List<Greeting> greetings = pluginManager.getExtensions(Greeting.class);

I am not sure yet if the variant with new AsyncPluginManager interface and DefaultAsyncPluginManager class is the best design option. I don’t know if the variant with add the new async methods directly in PluginManager is not better.

For the entire discussion about the Async API request, please see this.

PF4J Plugin Framework for Java

Async

Load and start plugins sync

Load and start plugins async