A modular, thread-safe gateway engine for simulating and connecting to multiple financial exchanges using configurable protocols like FIX and JSON. Built for flexibility, observability, and realism — designed and developed by Sam Parlatore.

ParlAquatics Gateway is a Java-based backend system that:

• Connects to multiple simulated or real exchange endpoints
• Dispatches each connection to a protocol-specific handler
• Supports FIX, JSON, and pluggable protocols via a factory-based architecture
• Uses config-driven concurrency, retry logic, and connection windows
• Designed for extensibility, testability, and production-grade robustness

curl -L https://raw.githubusercontent.com/samparlatore/ParlaGateway/refs/heads/master/run.ps1 > run.ps1
./run.ps1

curl -L https://raw.githubusercontent.com/samparlatore/ParlaGateway/refs/heads/master/run.sh > run.sh
./run.sh

+------------------+
|   GatewayCore    |
|------------------|
| - Thread pool    |
| - Retry logic    |
| - Config loader  |
+--------+---------+
         |
         v
+--------------------------+
| ExchangeHandlerFactory   |
+--------------------------+
         |
         v
+------------------+     +------------------+
| FixProtocolHandler|     |JsonProtocolHandler|
+------------------+     +------------------+
         |
         v
   [Socket Connection]

Exchange behavior is defined in NmsExchangeConfig objects, loaded from a config file or database. Each config includes:

• name
• acronym: Unique exchange ID
• ipAddress
• port: Target endpoint
• handlerName: Protocol handler to use (fix, json, etc.)
• connectionRetries,
• retryInterval,
• startTime,
• endTime:
• Connection policy

Global gateway settings (e.g., thread pool model) are loaded from a Properties file:

gateway.threadingModel=fixed
gateway.threadPoolSize=12
gateway.retryBackoffStrategy=exponential
gateway.retrySchedulerThreads=4

• Handlers implement the ExchangeHandler interface:
• Each handler is created by a dedicated factory:
• This ensures thread-safe, config-aware instantiation per exchange.

• ✅ fix — via QuickFIX/J (FIX 4.2, 4.4 supported)
• ✅ json — simple echo-style JSON handler
• 🧩 Add your own by implementing ExchangeHandler and registering a factory

Configurable via :

• fixed (default)
• cached
• scheduled
• workStealing

Each exchange runs in its own thread, with retry logic and jittered backoff.

<dependency>
  <groupId>org.quickfixj</groupId>
  <artifactId>quickfixj-core</artifactId>
  <version>2.0.0</version>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
  <version>1.7.22</version>
</dependency>

Add only the FIX message versions you need (e.g., quickfix-messages-fix42, fix44, etc.).

Use DefaultExchangeServer to simulate echo servers or stub protocols. You can also spin up local servers to test connection logic and retry behavior.

• Thread-safe by design: No shared mutable state across handlers
• Config-driven: Behavior is defined by and files
• Extensible: Add new protocols with minimal boilerplate
• Observable: Logs connection attempts, retries, and handler activity

Built by Sam Parlatore GitHub: github.com/samparlatore