add request event

src/main/java/me/hsgamer/yatpa/event/TeleportRequestEvent.java

@@ -0,0 +1,40 @@
+package me.hsgamer.yatpa.event;
+
+import me.hsgamer.yatpa.request.RequestEntry;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
+
+public class TeleportRequestEvent extends Event implements Cancellable {
+    private static final HandlerList HANDLERS = new HandlerList();
+    private final RequestEntry requestEntry;
+    private boolean cancelled;
+
+    public TeleportRequestEvent(RequestEntry requestEntry) {
+        this.requestEntry = requestEntry;
+    }
+
+    public static @NotNull HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    public RequestEntry getRequestEntry() {
+        return requestEntry;
+    }
+
+    @Override
+    public @NotNull HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancel) {
+        this.cancelled = cancel;
+    }
+}

src/main/java/me/hsgamer/yatpa/request/RequestManager.java

@@ -3,6 +3,7 @@
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import me.hsgamer.yatpa.YATPA;
+import me.hsgamer.yatpa.event.TeleportRequestEvent;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.UUID;
@@ -30,6 +31,12 @@ public RequestStatus request(RequestEntry requestEntry) {
             return RequestStatus.ALREADY_SENT;
         }
 
+        TeleportRequestEvent event = new TeleportRequestEvent(requestEntry);
+        plugin.getServer().getPluginManager().callEvent(event);
+        if (event.isCancelled()) {
+            return RequestStatus.CANCELLED;
+        }
+
         requestTable.put(requester, target, requestEntry);
         return RequestStatus.SUCCESS;
     }

src/main/java/me/hsgamer/yatpa/request/RequestStatus.java

@@ -3,4 +3,5 @@
 public enum RequestStatus {
     SUCCESS,
     ALREADY_SENT,
+    CANCELLED,
 }