Added ShopSellEvent as well as integrations for zShop, EconomyShopGUI, and DeluxeSellwands

eco-api/src/main/java/com/willfp/eco/core/integrations/shop/ShopSellEvent.java

@@ -0,0 +1,104 @@
+package com.willfp.eco.core.integrations.shop;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Unified event for shop plugins to fire in order to have sell multipliers.
+ */
+public class ShopSellEvent extends PlayerEvent {
+    /**
+     * The event handler list.
+     */
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    /**
+     * The sell price.
+     */
+    private double price;
+
+    /**
+     * The item to be sold.
+     */
+    @Nullable
+    private final ItemStack item;
+
+    /**
+     * Create new shop sell event.
+     *
+     * @param who   The player.
+     * @param price The price.
+     * @param item  The item.
+     */
+    public ShopSellEvent(@NotNull final Player who,
+                         final double price,
+                         @Nullable final ItemStack item) {
+        super(who);
+
+        this.price = price;
+        this.item = item;
+    }
+
+    /**
+     * Get the price.
+     *
+     * @return The price.
+     */
+    public double getPrice() {
+        return this.price;
+    }
+
+    /**
+     * Set the price.
+     *
+     * @param price The price.
+     */
+    public void setPrice(final double price) {
+        this.price = price;
+    }
+
+    /**
+     * Get the item to be sold.
+     *
+     * @return The item. Can be null for some plugins, so check hasKnownItem first!
+     */
+    @Nullable
+    public ItemStack getItem() {
+        return item;
+    }
+
+    /**
+     * Get if the item is known. Some shop plugins are lacking this in their event,
+     * so always check this before getItem(), as getItem() may be null.
+     *
+     * @return If the item is known.
+     */
+    public boolean hasKnownItem() {
+        return item != null;
+    }
+
+    /**
+     * Bukkit parity.
+     *
+     * @return The handlers.
+     */
+    @NotNull
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    /**
+     * Bukkit parity.
+     *
+     * @return The handlers.
+     */
+    @NotNull
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}