# community-marketplace

> Builds player auction house and trading functionality for L2J server.
Use when: implementing player-to-player item trading, auction listings, marketplace UI, buy/sell transactions, offline payment systems, or marketplace fee/tax calculations

- Author: valeriybaranyshyn-pixel
- Repository: valeriybaranyshyn-pixel/Tales-of-Aden
- Version: 20260202145225
- Stars: 0
- Forks: 0
- Last Updated: 2026-02-06
- Source: https://github.com/valeriybaranyshyn-pixel/Tales-of-Aden
- Web: https://mule.run/skillshub/@@valeriybaranyshyn-pixel/Tales-of-Aden~community-marketplace:20260202145225

---

---
name: community-marketplace
description: |
  Builds player auction house and trading functionality for L2J server.
  Use when: implementing player-to-player item trading, auction listings, marketplace UI, buy/sell transactions, offline payment systems, or marketplace fee/tax calculations
allowed-tools: Read, Edit, Write, Glob, Grep, Bash
---

# Community Marketplace Skill

Player auction house system for Tales of Aden L2J server. The marketplace uses the Community Board (BBS) UI with bypass handlers for navigation. Items are stored in `auction_table` with concurrent memory cache via `ConcurrentHashMap`. Supports both online and offline seller payment, configurable fees, and item filtering by grade/category.

## Quick Start

### Opening Marketplace

```java
// Voiced command: .MarketPlace
public class CommandMarketPlace implements IVoicedCommandHandler {
    private static final String[] _voicedCommands = {"MarketPlace"};
    
    @Override
    public boolean useVoicedCommand(String command, Player activeChar, String params) {
        if (command.equals("MarketPlace"))    
            MarketplaceCBBypasses.showMarketBoard(activeChar, 1, "*null*");  
        return true;
    }
}
```

### Listing an Item for Sale

```java
// Create auction entry with fee validation
int feeId = Config.MARKETPLACE_FEE[0];
int feeAmount = Config.MARKETPLACE_FEE[1];

if (activeChar.getInventory().getInventoryItemCount(feeId, -1) < feeAmount) {
    activeChar.sendMessage("You don't have enough to pay the fee.");
    return false;
}

AuctionTableCommunity.getInstance().addItem(new AuctionHolder(
    AuctionTableCommunity.getInstance().getNextAuctionId(),
    activeChar.getObjectId(),
    item.getItemId(),
    itemAmount,
    item.getEnchantLevel(),
    costId,
    costCount
));

activeChar.destroyItemByItemId("Auction Fee", feeId, feeAmount, activeChar, true);
activeChar.destroyItem("Auction Item", itemId, itemAmount, activeChar, true);
```

### Processing a Purchase

```java
// Calculate tax and pay seller
long cost = item.getCostCount();
long tax = 0;
if (cost >= Config.AUCTION_TAX_MINIMUM_ITEM_COUNT)
    tax = (long) Math.ceil(cost * Config.AUCTION_TAX_RATE);
long finalAmount = Math.max(0, cost - tax);

Player owner = L2World.getInstance().getPlayer(item.getOwnerId());
if (owner != null && owner.isOnline()) {
    owner.addItem("Auction", item.getCostId(), (int) finalAmount, null, true);
} else {
    addItemToOffline(item.getOwnerId(), item.getCostId(), (int) finalAmount);
}
```

## Key Concepts

| Concept | Usage | Example |
|---------|-------|---------|
| AuctionHolder | Data container for listings | `new AuctionHolder(id, owner, itemId, count, enchant, costId, costCount)` |
| AuctionTableCommunity | Singleton manager + DB persistence | `AuctionTableCommunity.getInstance().addItem(item)` |
| IBypassHandler | Community Board navigation | `handleBypass("bp_buy 123", player)` |
| HtmlBuilder | L2 client HTML with length limits | `new HtmlBuilder(HtmlType.COMUNITY)` |

## Configuration

| Config Key | Purpose | Default |
|------------|---------|---------|
| `MARKETPLACE_FEE` | Listing fee `[itemId, amount]` | Server-specific |
| `TICKET_MARKE_PLACE` | Sale currency item ID | `9511` (Donate coin) |
| `AUCTION_TAX_RATE` | Percentage taken from sale | `0.05` (5%) |
| `AUCTION_TAX_MINIMUM_ITEM_COUNT` | Minimum price for tax | `5` |
| `ENABLE_GRADE_ITEMS_MARKETPLACE` | Restrict by item grade | `false` |

## See Also

- [patterns](references/patterns.md)
- [workflows](references/workflows.md)

## Related Skills

- See the **mariadb** skill for database schema and connection pooling
- See the **l2j-gameserver** skill for bypass handler registration and packet handling
- See the **item-handlers** skill for inventory operations
- See the **database-schema** skill for the `auction_table` structure