Documentation/Messaging
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Use cases
Event Management
Each component/application generates many different types of events. A centralized event manager (Hub and Spoke) can be used to aggregate/dispatch events
- Synchronization: Window/Leveling events in one window should be synchronized across all viewer windows
- Temporal calibration: Different components have different update frequency, a centralized manager can be used to filter UpdateEvents, so the whole system is updating at the same frequency
System Integration
Different system/application have different data format or are running on different physical devices. A event bus can be used for system integration
Solution
- UseMessage Broker for event management
- Use Message Bus and Publisher/Subscriber design pattern for system integration
Implementation
- Message layer: OpenIGTLink
- OpenIGTLink defines many common data format and message structure
- It has plain vanilla socket support, might switch to ZeroMQ for transportation
- Transportation layer abstraction: ZeroMQ
- ZeroMQ is a small and fast implementation of the Advanced Message Queuing Protocol under the LGPL license
- It supports both synchronous and asynchronous messaging mode
- It supportsTCP, Multicast/PGM, Inter-process, and inter-thread transportation
- CMake version of library can be found here http://github.com/PatrickCheng/zeromq2
- API can be found here http://api.zeromq.org/zmq.html