Decibel Java Submit Order Example

This project demonstrates how to submit orders to the Decibel DEX using Java and the Japtos SDK.

Overview

This project includes two example applications:

1. OrderExample: Submit a single order to the APT-PERP market
2. BulkOrderExample: Interactive bulk order management bot that maintains a spread around a mid price

Both examples demonstrate:

• Account initialization (from private key or new generation)
• Automatic funding via Netna faucet
• USDC minting and deposit to subaccount
• Derived address calculation (subaccount, market)
• Transaction building and submission using the Japtos SDK

Prerequisites

• Java 17 or higher
• Maven 3.6+
• Access to the Decibel DEX deployment on Netna testnet

Note: No private key or pre-funded account required! The example automatically generates a new account and funds it.

Project Structure

.
├── pom.xml                                    # Maven configuration
├── src/
│   └── main/
│       ├── java/
│       │   └── com/decibel/
│       │       ├── OrderExample.java          # Single order example
│       │       ├── BulkOrderExample.java      # Bulk order bot example
│       │       ├── DecibelTransactions.java   # Transaction utilities
│       │       ├── DecibelUtils.java          # Address derivation & utils
│       │       └── InputUtils.java            # Config & account loading
│       └── resources/
│           └── config.properties.example      # Configuration template
└── README.md                                  # This file

Setup

1. Install Dependencies

The project uses Maven to manage dependencies. The Japtos SDK will be automatically downloaded when you build the project.

2. Configure Your Account (Optional)

Copy the example configuration file:

cp src/main/resources/config.properties.example src/main/resources/config.properties

Edit config.properties to customize:

# Aptos network configuration
aptos.fullnode.url=https://api.netna.staging.aptoslabs.com/v1
chain.id=204

# Decibel deployment package address
deployment.package=0x1234...

# Optional: Provide a private key (if not provided, a new account is generated)
private.key=0xYOUR_PRIVATE_KEY_HEX

# Trading API URL (for bulk orders)
trading.api.url=https://api.netna.aptoslabs.com/decibel

Note: If you don't provide a private key, a new account will be automatically generated and funded.

Building

Compile and package the application:

mvn clean package

This creates a self-contained JAR file in target/decibel-java-example-1.0-SNAPSHOT.jar.

Running

Single Order Example

Submit a single order to the APT-PERP market:

# Using Maven
mvn exec:java -Dexec.mainClass="com.decibel.OrderExample"

# Or using the JAR directly
java -cp target/decibel-java-example-1.0-SNAPSHOT.jar com.decibel.OrderExample

Bulk Order Example

Run the interactive bulk order bot:

# Using Maven
mvn exec:java -Dexec.mainClass="com.decibel.BulkOrderExample"

# Or using the JAR directly
java -cp target/decibel-java-example-1.0-SNAPSHOT.jar com.decibel.BulkOrderExample

The bulk order bot provides an interactive interface:

• Press 1 + ENTER to move all orders UP 1%
• Press 2 + ENTER to move all orders DOWN 1%
• Press f + ENTER to fund account (faucet + mint + deposit)
• Press x + ENTER to cancel orders and exit

Expected Output

Single Order Example

INFO  - Loaded account from private key: 0x123abc...
INFO  - Market: 0xe6de4f6ec47f1bc2ab73920e9f202953e60482e1c1a90e7eef3ee45c8aafee36
INFO  - Subaccount: 0x789ghi...
INFO  - Order: BUY 100000 @ 10000000 (TIF: 2, ReduceOnly: false)
INFO  - Submitting transaction...
INFO  - Transaction submitted: 0xabc123...
INFO  - Transaction committed successfully!

✅ Single order submitted successfully!
Transaction Hash: 0xabc123...
View on explorer:
https://explorer.aptoslabs.com/txn/0xabc123...?network=decibel

Bulk Order Example

🤖 Interactive Bulk Order Bot
==============================
Mid Price: $2.60
Spread: ±1% and ±2%

Press '1' + ENTER to move all orders UP 1% (↑)
Press '2' + ENTER to move all orders DOWN 1% (↓)
Press 'f' + ENTER to fund account (faucet + mint + deposit)
Press 'x' + ENTER to cancel orders and exit

Enter command (1/2/f/x): 1
↑ Moving UP to mid $2.63
✅ Orders updated | Tx: 0xdef456...

Enter command (1/2/f/x): x
🛑 Cancelling orders and stopping bot...
✅ Orders cancelled | Tx: 0x789abc...

How It Works

Account Initialization

The examples support two modes:

1. Existing Account: Load from private.key in config.properties
2. New Account: Generate a new Ed25519 account and automatically fund it

When generating a new account, the code:

• Creates a random Ed25519 account using SecureRandom
• Requests APT from the Netna faucet
• Mints 100 USDC to the account
• Deposits 50 USDC to the primary subaccount

Bulk Order Bot

The BulkOrderExample maintains a spread around a mid price:

• Fetches the current bulk order sequence number from the trading API
• Places 2 bids (1% and 2% below mid) and 2 asks (1% and 2% above mid)
• Allows interactive adjustment of the mid price up/down by 1%
• Automatically cancels and replaces orders with each update
• Increments the sequence number to avoid conflicts

Address Derivation

The example derives the primary subaccount address using the same logic as the TypeScript SDK:

Primary Subaccount Address: Derived from the user's account address using the seed "decibel_dex_primary" with SHA3-256 hashing and the Aptos object address marker (0xFE).

The market address for APT_USDC is configured directly: 0xe6de4f6ec47f1bc2ab73920e9f202953e60482e1c1a90e7eef3ee45c8aafee36

Transaction Functions

The examples use several Move entry functions:

Single Order:

<package>::dex_accounts::place_order_to_subaccount(
    subaccount_addr: address,
    market_addr: address,
    price: u64,
    size: u64,
    is_buy: bool,
    time_in_force: u8,
    is_reduce_only: bool,
    client_order_id: Option<u64>,
    stop_price: Option<u64>,
    tp_trigger_price: Option<u64>,
    tp_limit_price: Option<u64>,
    sl_trigger_price: Option<u64>,
    sl_limit_price: Option<u64>,
    builder_addr: Option<address>,
    builder_fee: Option<u64>
)

Bulk Orders:

<package>::dex_accounts::place_bulk_order_to_subaccount(
    market_addr: address,
    sequence_num: u64,
    bid_prices: vector<u64>,
    bid_sizes: vector<u64>,
    ask_prices: vector<u64>,
    ask_sizes: vector<u64>
)

Cancel Bulk Orders:

<package>::dex_accounts::cancel_bulk_order_to_subaccount(
    market_addr: address,
    sequence_num: u64
)

Japtos SDK

This project uses the Japtos SDK which provides:

• Ed25519 Cryptography: Account creation and transaction signing
• Transaction Building: Raw transaction construction and BCS serialization
• HTTP Client: Interaction with Aptos fullnode APIs
• Type Safety: Strongly-typed transaction arguments and payloads

Network Configuration

By default, the example connects to the Netna testnet. To use a different network:

1. Update aptos.fullnode.url in config.properties
2. Update chain.id to match the target network
3. Update deployment.package if using a different contract deployment

Available Networks

• Netna (default): https://api.netna.staging.aptoslabs.com/v1 (Chain ID: 204)
• Local: http://localhost:8080/v1 (use LOCAL_DEPLOYMENT addresses)
• Mainnet: Configure accordingly (coming soon)

Troubleshooting

"Faucet request failed"

The Netna faucet might be rate-limited or temporarily unavailable. Wait a few minutes and try again.

"Insufficient USDC balance"

The example mints 100 USDC and deposits 50 to the subaccount. If you get balance errors, check that the minting and deposit transactions completed successfully.

"Transaction simulation failed"

This usually means the market doesn't exist or the order parameters are invalid. Make sure you're using the correct market address in config.properties.

"SHA3-256 algorithm not available"

The Java runtime should include SHA3-256 support by default in Java 9+. If you're using an older version, you may need to add a cryptography provider.

Related Resources

• Decibel DEX Documentation
• Japtos SDK GitHub
• Aptos Documentation
• TypeScript SDK Reference

License

This example is part of the Decibel DEX project. See the main repository for license information.