P2P Tactical Board

About this project

As a second-year CS student, I built this project to showcase what I've learned so far in school — Java, OOP design patterns, and network socket programming. The goal was to create something that ties these concepts together in a practical way, with a focus on security industry applications.

I also used AI-assisted context engineering to speed up development. By providing clear requirements and constraints to an AI model, I was able to focus on understanding the architecture while getting help with boilerplate code and documentation.

Features

Tab-Based Interface

The application uses a tabbed interface with four main sections:

• Chat - Messenger-style communication with priority alerts
• Map - Shared tactical map with pathfinding and zones
• Audit Log - Security event logging and export
• Check-in - Lone worker safety system

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Chat System

Messenger-Style Communication

• Real-time synchronized chat between Host and Client
• Messages are color-coded by sender (Host = blue, Client = red)
• System messages in gray (italic)
• Type and press Enter or click Send

Priority Alerts System

Three priority levels for messages:

• Normal - Standard message display
• Alert - Orange text with [ALERT] prefix, screen flashes orange twice
• Critical - Red, bold, larger text with [CRITICAL] prefix, screen flashes red three times with audio alert

Self-Destructing Messages

• Set a timer (1-300 seconds) for messages to auto-delete
• Messages display [SD: Xs] indicator
• After expiration, shows "[Message self-destructed]" notification
• Useful for sensitive tactical communications

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Shared Map with Pathfinding

Pre-loaded Grid

• Yellow points with green connecting lines on white background
• Approximately half the grid points randomly removed for more working space

Point Operations

• Add points: Left-click empty space (auto-connects to nearest point)
• Add edges: Click your point, then click another point to create custom edge
• Delete points: Right-click your own points (grid points are permanent)

Color Coding

Border Color	Meaning
Gray	Grid points (permanent system points)
Blue	Host's points
Red	Client's points

Pathfinding with Dijkstra

• Find Path: Select your point as source → other user's point as destination
• Uses Dijkstra's algorithm with edge length (pixel distance) as weight
• Multiple paths can coexist with different colors
• Parallel edges drawn when paths share the same line
• Path length displayed in pixel distance
• Path events posted to chat automatically

Geofencing (Map Zones)

• Add Zone: Click two corners to create a rectangular zone
• Add Circle Zone: Click two corners to create a circular zone
• Zones displayed as semi-transparent overlays (blue for rectangles, red for circles)
• Dashed borders with zone labels
• Zone events logged to audit trail

Patrol Routes

• Create Patrol: Click 3+ points to define checkpoint route
• Start Patrol: Begins simulated patrol with 3-second intervals per checkpoint
• End Patrol: Manually stop current patrol
• Routes shown as dashed green lines with numbered checkpoints
• Current checkpoint highlighted in green
• Progress posted to chat and audit log

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Audit Log

Event Logging

Records all security-relevant events with timestamps:

• Connections and disconnections
• Messages sent and received
• Points and edges added/removed
• Paths found and removed
• Zones created and triggered
• Patrol started, progress, completed
• Check-in success, missed, reset
• Self-destruct events

Features

• Real-time log display in dedicated tab
• Export: Save log to file for compliance records
• Refresh: Update display with latest entries
• Clear: Reset log (clearing is itself logged)

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Check-in System (Lone Worker Safety)

How It Works

1. Click Start to begin the countdown timer (default 60 seconds)
2. Click Check In before time runs out to reset the timer
3. If you miss a check-in, your peer is immediately alerted
4. Click Stop to end the monitoring session

Visual Feedback

• Green: Plenty of time remaining (>30s)
• Orange: Warning zone (10-30s)
• Red: Critical (<10s)
• Flashing red: Missed check-in alert

Network Alerts

• Successful check-ins notify your peer
• Missed check-ins trigger alert on peer's screen with audio

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How to Run

Compile

javac -d target/classes src/main/java/com/tactical/p2p/*.java

Option 1: Run on Same Machine (Local Testing)

Terminal 1 (Host):

java -cp target/classes com.tactical.p2p.App host

Terminal 2 (Client):

java -cp target/classes com.tactical.p2p.App client

When prompted, enter 127.0.0.1 or localhost as the host address.

Or just run without args and pick from the GUI dialog.

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Option 2: Run Between Two Different Devices (Network)

This allows you to run the Host on one computer and connect from a Client on a different computer over your local network.

Step 1: Find the Host's IP Address

On Windows (Host machine):

ipconfig

Look for "IPv4 Address" under your active network adapter (e.g., 192.168.1.100)

On Mac/Linux (Host machine):

ifconfig
# or
ip addr show

Look for inet under your active network (e.g., 192.168.1.100)

Step 2: Start the Host

On Device 1 (the server):

java -cp target/classes com.tactical.p2p.App host

1. A dialog will appear - set a 4-digit PIN (e.g., 1234)
2. The host will wait for a client connection on port 8888
3. Note the IP address you found in Step 1

Step 3: Start the Client

On Device 2 (the client):

java -cp target/classes com.tactical.p2p.App client

Or with the host IP directly:

java -cp target/classes com.tactical.p2p.App client 192.168.1.100

1. A dialog will appear asking for the host address
2. Enter the Host's IP address (e.g., 192.168.1.100)
3. Enter the PIN when prompted
4. You should now be connected!

Step 4: Verify Connection

• Both devices should show "Status: Connected" in the status bar
• Try sending a chat message from one device to the other
• The Host is shown in blue, Client in red

Troubleshooting

Problem	Solution
Connection timeout	Check both devices are on the same network
Connection refused	Ensure Host is running and waiting for connection
Firewall blocking	Allow Java through Windows Firewall or disable temporarily
Wrong IP	Verify IP with ipconfig / ifconfig - use the local network IP, not public IP
PIN rejected	Host sets the PIN on startup - make sure you enter the same PIN

Command-Line Reference

Command	Description
java -cp target/classes com.tactical.p2p.App	Show mode selection dialog
java -cp target/classes com.tactical.p2p.App host	Start as Host (skip dialog)
java -cp target/classes com.tactical.p2p.App client	Start as Client, show host address dialog
java -cp target/classes com.tactical.p2p.App client 192.168.1.100	Start as Client connecting to specific IP

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Project Structure

src/main/java/com/tactical/p2p/
├── App.java                 # Main class, handles startup
├── StateModel.java          # Stores the shared state
├── NetworkManager.java      # Socket communication
├── SyncBoardUI.java         # Main GUI with tabs
├── MapScreen.java           # Map panel with points, lines, zones, patrols
├── Point.java               # 2D point class (ratio coordinates)
├── Line.java                # Line with start/end points
├── PathStrategy.java        # Strategy interface for pathfinding
├── ShortestPathStrategy.java # Dijkstra implementation
├── AuditLogger.java         # Security audit logging
└── CheckInManager.java      # Lone worker safety system

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Network Protocol

Uses TCP sockets on port 8888. Messages are UTF-8 strings ending with newline.

Message Types

Format	Description
MSG:sender:priority:text:sd	Chat message with priority and self-destruct
POINT:ACTION:x:y:fromHost	Point add/remove
EDGE:x1:y1:x2:y2	Custom edge added
PATH:sx:sy:dx:dy	Path found
PATHREMOVE:index	Path removed
CHECKIN:user	User checked in
CHECKIN_MISSED:user	User missed check-in
SD:id	Message self-destructed

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Design Patterns

Strategy Pattern

public interface PathStrategy {
    List<Line> findPath(Point source, Point target, List<Point> points, List<Line> lines);
    String getName();
}

Allows swapping pathfinding algorithms without changing client code.

Observer Pattern

• StateModel notifies listeners when data changes
• Callbacks throughout for event-driven architecture

MVC Architecture

• StateModel = Model
• SyncBoardUI, MapScreen = View/Controller
• AuditLogger, CheckInManager = Services

Dependency Injection

• Dependencies passed via constructor
• Callbacks set via setter methods

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Threading Model

• EDT (Event Dispatch Thread): All GUI updates
• Background threads: Network I/O (socket read/write)
• SwingUtilities.invokeLater() for thread-safe UI updates
• Swing Timers for countdown, patrol simulation, screen flashing

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Requirements

• Java 11 or higher
• No external libraries

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Use Cases

This application simulates a tactical coordination system suitable for:

• Security team coordination
• Event management and monitoring
• Lone worker safety compliance
• Patrol route management
• Geofenced area monitoring

Made for a distributed systems learning project with security industry focus.