- Multiple users can draw on a shared interactive canvas.
- The system will support a single whiteboard shared between all clients.
- Key Elements with GUI:
- Shapes: The whiteboard should support lines, circles, ovals, and rectangles.
- Free draw and erase functionality (multiple sizes of eraser are convenient).
- Text input: Users can type text anywhere inside the whiteboard.
- Users can choose their favorite drawing color from at least 16 available colors.
- Creativity and innovation are encouraged.
- Chat Window (text-based): Users can communicate with each other by typing messages.
- "File" menu with options for new, open, save, saveAs, and close (manager control only).
- Manager can kick out a certain peer/user from the whiteboard.
- Dealing with concurrency:
- Properly handling access to shared resources.
- Ensuring simultaneous actions lead to a reasonable state.
- Structuring the application and handling system state:
- Multiple servers or a single central one managing all system state.
- Dealing with networked communication:
- Deciding message sending across the network.
- Designing an exchange protocol for messages and replies.
- Designing remote interfaces and servants if using RMI.
- Implementing the GUI:
- Functionality similar to tools like MS Paint.
- Use of any tool/API/library, e.g., Java2D drawing package.
Develop a whiteboard that can be shared between multiple users over the network.
- Implemented in Java, with freedom to choose technology (e.g., Sockets) for the distributed application.
- Choice of Sockets, TCP, or UDP.
- Definition of message format and exchange protocol (XML-based or custom).
- Clients can broadcast message updates to all other clients, with acknowledgments.
- Consideration of Java RMI, remote objects/interfaces.
- Choice of file or database for storage.
- Use of technology of choice, ensuring the selected technology can achieve the goal. If uncertain, stick to familiar technologies.
mvn clean package| Option | Description | Usage | Example |
|---|---|---|---|
-RCMD |
控制每秒允许的更新次数，影响数据推送的频率。 Controls the number of updates allowed per second, affecting the data push frequency. |
-RCMD <number> |
-RCMD 120 表示每秒更新120次。-RCMD 120 means 120 updates per second. |
-SHOWALL |
设置是否同步所有预览。启用此选项可能增加网络负载和系统延迟。 Sets whether to sync all previews. Enabling this option may increase network load and system latency. |
-SHOWALL <true\false> |
-SHOWALL true 同步所有预览。-SHOWALL true to sync all previews. SHOWALL false 不完全同步，提高性能。SHOWALL false for unsynced previews, improves performance. |
-DDL |
设置延迟容忍度，单位为秒。绘制操作若超过此时间则被取消，控制操作的实时性。 Sets the delay tolerance in seconds. Operations exceeding this time limit will be canceled, controlling the timeliness of operations. |
-DDL <seconds> |
-DDL 3 如果绘制延迟超过3秒，则取消。-DDL 3 cancels the operation if the delay exceeds 3 seconds. |
-FCOFF |
控制是否关闭流量控制。关闭流控可以减少延迟，但可能增加网络拥堵风险。 Controls whether to turn off flow control. Turning off flow control can reduce latency but may increase the risk of network congestion. |
-FCOFF <true\false> |
-FCOFF true 关闭流控功能。-FCOFF true to turn off flow control. |
120 updates per second, no need to sync all previews (intermittent updates)
java -jar .\target\WBServer.jar 127.0.0.1 8611 WB1 -RCMD 120 -SHOWALL falsejava -jar .\target\WBClient.jar 127.0.0.1 8611 WinstonLiUnderfined whiteboard name, 240 updates per second, sync all previews (may cause lag)
java -jar .\target\WBServer.jar 127.0.0.1 8611 -RCMD 240 -SHOWALL true -DDL 5java -jar .\target\WBClient.jar 127.0.0.1 8611 WinstonLi- 注意，客户侧容忍度为DDL+2 Note that the client side tolerance is DDL+2
java -jar .\target\WBServer.jar 127.0.0.1 8611 -RCMD 240 -SHOWALL true -DDL 2java -jar .\target\WBClient.jar 127.0.0.1 8611 TonyMaTurn off flow control explicitly (Similar to the ample default setting)
java -jar .\target\WBServer.jar 127.0.0.1 8611 WB1 -SHOWALL true -FCOFF truejava -jar .\target\WBClient.jar 127.0.0.1 8611 StephenJobs