Added an event fired on hopper access.

src/main/java/com/songoda/epichoppers/api/events/HopperAccessEvent.java

@@ -0,0 +1,40 @@
+package com.songoda.epichoppers.api.events;
+
+import com.songoda.epichoppers.hopper.Hopper;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+
+/**
+ * Called when a hopper is accessed by a player.
+ */
+public class HopperAccessEvent extends HopperEvent implements Cancellable {
+
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    private boolean canceled = false;
+
+    public HopperAccessEvent(Player player, Hopper hopper) {
+        super(player, hopper);
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return canceled;
+    }
+
+    @Override
+    public void setCancelled(boolean canceled) {
+        this.canceled = canceled;
+    }
+
+}

src/main/java/com/songoda/epichoppers/api/events/HopperEvent.java

@@ -0,0 +1,29 @@
+package com.songoda.epichoppers.api.events;
+
+import com.songoda.epichoppers.hopper.Hopper;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event;
+import org.bukkit.event.player.PlayerEvent;
+
+/**
+ * Represents an abstract {@link Event} given a {@link Player} and {@link Hopper} instance
+ */
+public abstract class HopperEvent extends PlayerEvent {
+
+    protected final Hopper hopper;
+
+    public HopperEvent(Player who, Hopper hopper) {
+        super(who);
+        this.hopper = hopper;
+    }
+
+    /**
+     * Get the {@link Hopper} involved in this event
+     *
+     * @return the broken spawner
+     */
+    public Hopper getHopper() {
+        return hopper;
+    }
+
+}

src/main/java/com/songoda/epichoppers/hopper/Hopper.java

@@ -4,6 +4,7 @@ import com.songoda.core.compatibility.ServerVersion;
 import com.songoda.core.gui.GuiManager;
 import com.songoda.core.hooks.EconomyManager;
 import com.songoda.epichoppers.EpicHoppers;
+import com.songoda.epichoppers.api.events.HopperAccessEvent;
 import com.songoda.epichoppers.gui.GUIOverview;
 import com.songoda.epichoppers.hopper.levels.Level;
 import com.songoda.epichoppers.player.PlayerData;
@@ -44,6 +45,13 @@ public class Hopper {
                 && Bukkit.getPlayer(lastPlayerOpened) != null) {
             Bukkit.getPlayer(lastPlayerOpened).closeInventory();
         }
+
+        HopperAccessEvent accessEvent = new HopperAccessEvent(player, this);
+        Bukkit.getPluginManager().callEvent(accessEvent);
+        if (accessEvent.isCancelled()) {
+            return;
+        }
+
         if (placedBy == null) placedBy = player.getUniqueId();
 
         EpicHoppers instance = EpicHoppers.getInstance();