feat: presumably completed the first version of the api

src/main/java/ftbsc/geb/api/GEB.java

@@ -0,0 +1,59 @@
+package ftbsc.geb.api;
+
+import java.lang.reflect.Constructor;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * The main event bus class.
+ * @since 0.1.0
+ */
+public class GEB {
+
+	/**
+	 * The identifier of this bus. Methods
+	 */
+	private final String identifier;
+
+	/**
+	 * A {@link Map} tying each user-defined event class to its machine-generated implementation.
+	 * In practice, the {@link Class} of the original event is used as key and mapped to each
+	 * class' generated {@link Constructor}.
+	 */
+	private final Map<Class<? extends IEvent>, Constructor<? extends IEvent>> eventMapper;
+
+	/**
+	 * The public constructor.
+	 * @param identifier a {@link String} uniquely identifying this bus
+	 */
+	public GEB(String identifier) {
+		this.identifier = identifier;
+		this.eventMapper = new ConcurrentHashMap<>();
+		for(IEvent event : ServiceLoader.load(IEvent.class)) {
+			try {
+				eventMapper.put(event.getOriginalEvent(), event.getClass().getConstructor(event.getClass()));
+			} catch(NoSuchMethodException ignored) {} //should never happen, this code is machine-generated
+		}
+	}
+
+	/**
+	 * @return the identifier of this bus
+	 */
+	public String getIdentifier() {
+		return identifier;
+	}
+
+	/**
+	 * Dispatches an event, calling all of its listeners that are subscribed to this bus.
+	 * TODO: make this as efficient as possible
+	 * @param event the event to fire
+	 * @return true if the event was canceled, false otherwise
+	 */
+	public boolean handleEvent(IEvent event) {
+		try {
+			return eventMapper.get(event.getClass()).newInstance(event).callListeners(this.getIdentifier());
+		} catch(ReflectiveOperationException ignored) {} //should never happen
+		return false;
+	}
+}

src/main/java/ftbsc/geb/api/IEvent.java

@@ -1,9 +1,27 @@
 package ftbsc.geb.api;
 
+/**
+ * The common interface for all GEB events.
+ * @since 0.1.0
+ */
 public interface IEvent {
-	default boolean isCanceled() {
+	/**
+	 * Any custom implementation of this method will be called just before the
+	 * calls to listeners, but its return values will be ignored. You probably
+	 * don't want to touch this.
+	 * @param identifier the identifier of the bus that's calling this
+	 * @return the value {@link GEB#handleEvent(IEvent)} will return for this
+	 */
+	default boolean callListeners(String identifier) {
 		return false;
 	}
 
-	void dispatch();
+	/**
+	 * Fetches the {@link Class} containing the original implementation of this.
+	 * If you wish to override this, make your override final.
+	 * @return the class of the original, non-extended superclass
+	 */
+	default Class<? extends IEvent> getOriginalEvent() {
+		return IEvent.class;
+	}
 }

src/main/java/ftbsc/geb/api/IEventCancelable.java

@@ -0,0 +1,22 @@
+package ftbsc.geb.api;
+
+/**
+ * The common interface for all cancelable GEB events.
+ * @since 0.1.0
+ */
+public interface IEventCancelable extends IEvent {
+	/**
+	 * Checks whether the event was canceled; any user-defined
+	 * implementation will be ignored.
+	 * @return whether the event was canceled
+	 */
+	default boolean isCanceled() {
+		return false;
+	}
+
+	/**
+	 * Cancels the event. Any user-defined implementation will
+	 * be ignored.
+	 */
+	default void setCanceled() {}
+}

src/main/java/ftbsc/geb/api/IListener.java

@@ -1,5 +1,12 @@
 package ftbsc.geb.api;
 
+/**
+ * The common interface for all classes that contain GEB listeners.
+ * @since 0.1.0
+ */
 public interface IListener {
-	boolean active();
+	/**
+	 * @return whether the listeners in this class should be considered to be active
+	 */
+	boolean isActive();
 }

src/main/java/ftbsc/geb/api/annotations/BusInstance.java

@@ -0,0 +1,17 @@
+package ftbsc.geb.api.annotations;
+
+import ftbsc.geb.api.GEB;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation should mark either a static instance of {@link GEB}
+ * or a static method returning one.
+ * @since 0.1.0
+ */
+@Target({ElementType.FIELD, ElementType.METHOD})
+@Retention(RetentionPolicy.CLASS)
+public @interface BusInstance {}

src/main/java/ftbsc/geb/api/annotations/Event.java

@@ -1,8 +1,17 @@
 package ftbsc.geb.api.annotations;
 
+import ftbsc.geb.api.IEvent;
+
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+/**
+ * Marks a class as an Event. It should implement the {@link IEvent} interface.
+ * It doesn't need to be abstract, but it can never be final.
+ * @since 0.1.0
+ */
 @Target(ElementType.TYPE)
-public @interface Event {
-}
+@Retention(RetentionPolicy.CLASS)
+public @interface Event {}

src/main/java/ftbsc/geb/api/annotations/Listen.java

@@ -1,14 +1,32 @@
 package ftbsc.geb.api.annotations;
 
+import ftbsc.geb.api.IEvent;
+import ftbsc.geb.api.IListener;
+
 import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
- * Marks the method as a listener.
- * Its parent must implement the {@link ftbsc.geb.api.IListener} interface.
- * The method should only take a single input value, an event.
+ * Marks the method as a listener. Its parent must implement the {@link IListener} interface.
+ * The annotated method should only take a single input value, an instance of {@link IEvent};
+ * it should be either void or boolean; if it's boolean, the return value indicates whether
+ * the event was canceled.
+ * @since 0.1.0
  */
 @Target(ElementType.METHOD)
+@Retention(RetentionPolicy.CLASS)
 public @interface Listen {
+	/**
+	 * @return an integer indicating priority level for the listener, defaulting to 0
+	 */
 	int priority() default 0;
+
+	/**
+	 * @return an array of {@link String}s specifying which buses they should be listening on;
+	 * 				 an empty array means that they should listen on all buses, ignoring identifiers:
+	 * 				 that's probably what you wanted anyway.
+	 */
+	String[] on() default {}; //empty array = listen on all of them
 }

src/main/java/ftbsc/geb/api/annotations/ListenerInstance.java

@@ -0,0 +1,17 @@
+package ftbsc.geb.api.annotations;
+
+import ftbsc.geb.api.IListener;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation should mark either be a static instance of {@link IListener}
+ * or a static method returning one.
+ * @since 0.1.0
+ */
+@Target({ElementType.FIELD, ElementType.METHOD})
+@Retention(RetentionPolicy.CLASS)
+public @interface ListenerInstance {}