Automatically provides key-value pairs for BentoBoxEvents (#775)

* Automatically provides key-value pairs for PremadeEvents

https://github.com/BentoBoxWorld/Challenges/pull/138

* Replaces PremadeEvent with BentoBoxEvent to make it look nicer.

* Cleaned up javadoc in BentoBoxEvent

* Cleaned up javadoc in PremadeEvent

* Added javadoc to async constructor in BentoBoxEvent

src/main/java/world/bentobox/bentobox/api/events/BentoBoxEvent.java

@@ -0,0 +1,75 @@
+package world.bentobox.bentobox.api.events;
+
+import java.beans.IntrospectionException;
+import java.beans.Introspector;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+
+/**
+ * Provides the default methods expected when extending {@link Event}.
+ * @author tastybento
+ * @since 1.5.3
+ */
+public abstract class BentoBoxEvent extends Event {
+
+    private static final HandlerList handlers = new HandlerList();
+
+    /**
+     * The default constructor is defined for cleaner code.
+     * This constructor assumes the BentoBoxEvent is synchronous.
+     */
+    public BentoBoxEvent() {
+        this(false);
+    }
+
+    /**
+     * Explicitly declares a BentoBoxEvent as synchronous or asynchronous.
+     * @param async - true indicates the event will fire asynchronously, false
+     *    by default from default constructor
+     */
+    public BentoBoxEvent(boolean async) {
+        super(async);
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return getHandlerList();
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+
+    /**
+     * Get a map of key value pairs derived from the fields of this class by reflection.
+     * @return map
+     * @since 1.5.3
+     */
+    public Map<String, Object> getKeyValues() {
+        try {
+            Map<String, Object> map = new HashMap<>();
+            Arrays.asList(Introspector.getBeanInfo(this.getClass(), PremadeEvent.class).getPropertyDescriptors())
+            .stream()
+            // only get getters
+            .filter(pd -> Objects.nonNull(pd.getReadMethod()))
+            .forEach(pd -> { // invoke method to get value
+                try {
+                    Object value = pd.getReadMethod().invoke(this);
+                    if (value != null) {
+                        map.put(pd.getName(), value);
+                    }
+                } catch (Exception ignore) {}
+            });
+            return map;
+        } catch (IntrospectionException e) {
+            // Oh well, nothing
+            return Collections.emptyMap();
+        }
+    }
+}

src/main/java/world/bentobox/bentobox/api/events/PremadeEvent.java

@@ -1,12 +1,13 @@
 package world.bentobox.bentobox.api.events;
 
 import org.bukkit.event.Event;
-import org.bukkit.event.HandlerList;
 
 /**
  * Provides the default methods expected when extending {@link Event}.
+ * @deprecated As of 1.5.3, for removal. Use {@link BentoBoxEvent} instead.
  */
-public abstract class PremadeEvent extends Event {
+@Deprecated
+public abstract class PremadeEvent extends BentoBoxEvent {
 
     /**
      * The default constructor is defined for cleaner code.
@@ -26,14 +27,4 @@ public abstract class PremadeEvent extends Event {
         super(async);
     }
 
-    private static final HandlerList handlers = new HandlerList();
-
-    @Override
-    public HandlerList getHandlers() {
-        return getHandlerList();
-    }
-
-    public static HandlerList getHandlerList() {
-        return handlers;
-    }
 }

src/main/java/world/bentobox/bentobox/api/events/addon/AddonBaseEvent.java

@@ -26,6 +26,7 @@ public class AddonBaseEvent extends PremadeEvent {
     /**
      * @return the keyValues
      */
+    @Override
     public Map<String, Object> getKeyValues() {
         return keyValues;
     }