feat(annotations): add command containers (#364)

This is the first part of the introduction of annotation processing to cloud. A new `@CommandContainer` annotation has been introduced, which can be placed on classes to have the annotation parser automatically construct & parse the classes when `AnnotationParser.parseContainers()` is invoked.

A future PR will introduce another processor that will scan for `@CommandMethod` annotations and verify the integrity of the annotated methods (visibility, argument annotations, etc.).

examples/example-bukkit/build.gradle.kts

@@ -18,6 +18,8 @@ dependencies {
     implementation(libs.adventurePlatformBukkit)
     /* Bukkit */
     compileOnly(libs.bukkit)
+    /* Annotation processing */
+    annotationProcessor(project(":cloud-annotations"))
 }
 
 tasks {

examples/example-bukkit/src/main/java/cloud/commandframework/examples/bukkit/ExampleCommandContainer.java

@@ -0,0 +1,53 @@
+//
+// MIT License
+//
+// Copyright (c) 2021 Alexander Söderberg & Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+package cloud.commandframework.examples.bukkit;
+
+import cloud.commandframework.annotations.AnnotationParser;
+import cloud.commandframework.annotations.CommandMethod;
+import cloud.commandframework.annotations.processing.CommandContainer;
+import org.bukkit.command.CommandSender;
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+@CommandContainer
+public final class ExampleCommandContainer {
+
+    /**
+     * The constructor. {@link AnnotationParser} is an optional parameter.
+     *
+     * @param parser the parser
+     */
+    public ExampleCommandContainer(final @NonNull AnnotationParser<CommandSender> parser) {
+        // Woo...
+    }
+
+    /**
+     * This one gets parsed automatically!
+     *
+     * @param sender the sender
+     */
+    @CommandMethod("container")
+    public void containerCommand(final CommandSender sender) {
+        sender.sendMessage("This is sent from a container!!");
+    }
+}

examples/example-bukkit/src/main/java/cloud/commandframework/examples/bukkit/ExamplePlugin.java

@@ -235,6 +235,12 @@ public final class ExamplePlugin extends JavaPlugin {
         // Parse all @CommandMethod-annotated methods
         //
         this.annotationParser.parse(this);
+        // Parse all @CommandContainer-annotated classes
+        try {
+            this.annotationParser.parseContainers();
+        } catch (final Exception e) {
+            e.printStackTrace();
+        }
         //
         // Base command builder
         //