LogHandler

LogHandler is a small asynchronous Java logging example built around the Composite design pattern. A log call is packaged with its level, message, logger name, and timestamp, then dispatched to console, file, and database handlers by separate worker threads.

Requirements

• Java 21 or later
• Maven 3.8 or later

Build and run

From the project root:

mvn clean package
java -cp target/classes com.rsr007.loghandler.Application

The sample application emits one message at each supported level: INFO, WARN, DEBUG, and ERROR. Each handler currently writes a labeled line to standard output. FileLogger and DbLogger are placeholders; they do not yet write to a file or connect to a database.

Use the logger

Create a CompositeLogger with the class that is producing the messages, then call the desired level method:

import com.rsr007.loghandler.core.Logger;
import com.rsr007.loghandler.impl.CompositeLogger;

public class Service {
    private static final Logger logger = new CompositeLogger(Service.class);

    public void process() {
        logger.info("Processing started");
        logger.warn("Using fallback configuration");
        logger.debug("Detailed diagnostic information");
        logger.error("Processing failed");

        // Call once when the application is finished logging.
        CompositeLogger.shutdown();
    }
}

The logger submits each message to three bounded queues (capacity 1,000 each). Dedicated workers consume those queues asynchronously. Call CompositeLogger.shutdown() when logging is complete so workers drain pending messages and stop. The current worker is shared statically and is intended to be shut down once, at application shutdown.

Project layout

src/main/java/com/rsr007/loghandler/
├── Application.java
├── core/       # Logger API, levels, and log event record
└── impl/       # Composite logger and output handlers

Maven coordinates

• Group: me.rsr007.loghandler
• Artifact: log-handler
• Version: 1.0.0