Add PreTransactionEvent (#6370)

Golfing7 · JRoy · web-flow · commit 08b7fe3bb8b5 · 2026-04-05T03:46:06.000Z
### Information  I added a PreTransactionEvent for cancelling transactions between users. ### Details **Proposed feature:** Adding a PreTransactionEvent. **Environments tested:**  OS: Linux Mint  Java version: 23  - [x] Most recent Paper version (1.XX.Y, git-Paper-BUILD) - [ ] CraftBukkit/Spigot/Paper 1.12.2 - [ ] CraftBukkit 1.8.8 **Demonstration:**  ```java @eventhandler public void onPay(PreTransactionEvent event) { // Prevent money from being sent outside their own faction. IUser userSource = event.getRequester().getUser(); if (userSource == null) return; FPlayer fplayerSource = FPlayers.getInstance().getByPlayer(userSource.getBase()); if (fplayerSource == null || fplayerSource.isAdminBypassing()) return; Faction faction = fplayerSource.getFaction(); if (faction == null || !isFactionVoluntaryExcluded(faction.getId())) return; // Who are they sending it to? FPlayer target = FPlayers.getInstance().getById(event.getTarget().getUUID().toString()); Faction factionTarget = target.getFaction(); if (faction != factionTarget) { event.setCancelled(true); msg(userSource.getBase(), cantPayOutsideExcludedFactionMessage); } } ``` This code prevents transactions between two users when two factions can't interact. --------- Co-authored-by: Josh Roy <10731363+JRoy@users.noreply.github.com>
diff --git a/Essentials/src/main/java/com/earth2me/essentials/User.java b/Essentials/src/main/java/com/earth2me/essentials/User.java
@@ -23,6 +23,7 @@
 import net.ess3.api.events.MuteStatusChangeEvent;
 import net.ess3.api.events.UserBalanceUpdateEvent;
 import net.ess3.provider.PlayerLocaleProvider;
+import net.essentialsx.api.v2.events.PreTransactionEvent;
 import net.essentialsx.api.v2.events.TransactionEvent;
 import net.essentialsx.api.v2.services.mail.MailSender;
 import org.bukkit.Location;
@@ -263,12 +264,20 @@ public void payUser(final User reciever, final BigDecimal value) throws Exceptio
         payUser(reciever, value, UserBalanceUpdateEvent.Cause.UNKNOWN);
     }
 
-    public void payUser(final User reciever, final BigDecimal value, final UserBalanceUpdateEvent.Cause cause) throws Exception {
+    public void payUser(final User reciever, BigDecimal value, final UserBalanceUpdateEvent.Cause cause) throws Exception {
         if (value.compareTo(BigDecimal.ZERO) < 1) {
             throw new Exception(tlLocale(playerLocale, "payMustBePositive"));
         }
 
         if (canAfford(value)) {
+            // Call an event for pre-transaction
+            final PreTransactionEvent preTransactionEvent = new PreTransactionEvent(this.getSource(), reciever, value);
+            ess.getServer().getPluginManager().callEvent(preTransactionEvent);
+            if (preTransactionEvent.isCancelled()) {
+                return;
+            }
+            value = preTransactionEvent.getAmount();
+
             setMoney(getMoney().subtract(value), cause);
             reciever.setMoney(reciever.getMoney().add(value), cause);
             sendTl("moneySentTo", AdventureUtil.parsed(NumberUtil.displayCurrency(value, ess)), reciever.getDisplayName());
diff --git a/Essentials/src/main/java/net/essentialsx/api/v2/events/PreTransactionEvent.java b/Essentials/src/main/java/net/essentialsx/api/v2/events/PreTransactionEvent.java
@@ -0,0 +1,59 @@
+package net.essentialsx.api.v2.events;
+
+import com.earth2me.essentials.CommandSource;
+import com.google.common.base.Preconditions;
+import net.ess3.api.IUser;
+import org.bukkit.Bukkit;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+
+import java.math.BigDecimal;
+
+/**
+ * Fired when a transaction (e.g. /pay) is about to be handled.
+ */
+public class PreTransactionEvent extends TransactionEvent implements Cancellable {
+    private static final HandlerList handlers = new HandlerList();
+
+    private boolean cancelled;
+
+    public PreTransactionEvent(final CommandSource requester, final IUser target, final BigDecimal amount) {
+        super(!Bukkit.isPrimaryThread(), requester, target, amount);
+    }
+
+    /**
+     * Sets the amount to be subtracted from the requester's balance.
+     * <p>
+     * Note: Changing this amount will not verify the requester actually has enough balance to complete the transaction.
+     * @param decimal the new amount
+     */
+    public void setAmount(final BigDecimal decimal) {
+        Preconditions.checkNotNull(decimal, "decimal cannot be null");
+        Preconditions.checkArgument(decimal.compareTo(BigDecimal.ZERO) >= 0, "decimal cannot be negative");
+
+        this.amount = decimal;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    /**
+     * If this event should be cancelled. If cancelled, no messages will be displayed to the users involved.
+     * @param cancelled whether this event should be cancelled
+     */
+    @Override
+    public void setCancelled(boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+}
diff --git a/Essentials/src/main/java/net/essentialsx/api/v2/events/TransactionEvent.java b/Essentials/src/main/java/net/essentialsx/api/v2/events/TransactionEvent.java
@@ -16,15 +16,19 @@ public class TransactionEvent extends Event {
 
     private final CommandSource requester;
     private final IUser target;
-    private final BigDecimal amount;
+    protected BigDecimal amount;
 
-    public TransactionEvent(CommandSource requester, IUser target, BigDecimal amount) {
-        super(!Bukkit.isPrimaryThread());
+    protected TransactionEvent(boolean async, CommandSource requester, IUser target, BigDecimal amount) {
+        super(async);
         this.requester = requester;
         this.target = target;
         this.amount = amount;
     }
 
+    public TransactionEvent(CommandSource requester, IUser target, BigDecimal amount) {
+        this(!Bukkit.isPrimaryThread(), requester, target, amount);
+    }
+
     /**
      * @return the user who initiated the transaction
      */
