This commit introduces a major refactoring of the MCP Java SDK to implement a session-based architecture
for server-side implementations. The changes improve the SDK's ability to handle multiple concurrent
client connections and provide an API better aligned with the MCP specification.
Key changes:
- Introduce McpServerTransportProvider interface to manage client connections
- Rename ClientMcpTransport to McpClientTransport and ServerMcpTransport to McpServerTransport
- Add exchange objects (McpAsyncServerExchange, McpSyncServerExchange) for client interaction
- Update handler signatures to include exchange parameter: (args) -> result to (exchange, args) -> result
- Rename Registration classes to Specification classes
- Update method names (e.g., rootsChangeConsumers to rootsChangeHandlers)
- Deprecate old interfaces and classes for removal in 0.9.0
- Add migration guide (migration-0.8.0.md)
Resolves#9, #15
Co-authored-by: Christian Tzolov <christian.tzolov@broadcom.com>
Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>
This change uses VirtualTimeScheduler and pretends enough time has
passed to trigger a timeout on the initialization.
Another problem with reliability of the tests was that the used
testcontainer for the SSE server does not support multiple clients and
the existence of both the global client for the entire suite and some
customized local clients in some tests caused responses to be delivered
to the other client at some racing situations. Now each test creates a
dedicated client and performs cleanup locally.
While these tests were improved, two other issues were found and fixed.
The first one is that the closeGracefully of DefaultMcpSession was not
lazy and would trigger connection disposal before the returned Mono was
subscribed. The second one was dealing with closing the StdIo client
before the process was started. In such a case there should not be an
error but rather a warning and successful completion.
- Add configurable initialization timeout separate from request timeout
- Rename ServletSse* test classes to HttpSse* for better naming consistency
- Replace direct .block() calls with StepVerifier for better reactive testing
- Change ping() method to return Mono instead of Mono
- Improve error handling and reactive programming patterns throughout tests
- Chain reactive operations for cleaner test flow
Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>
Introduce new builder patterns and enhance type safety
- Add new builder patterns for McpClient and McpServer with sync/async variants
- Introduce dedicated McpClientFeatures and McpServerFeatures classes
- Enhance type safety and reactive support with proper Mono integration
- Add migration guide for 0.6.0 release
- Mark old builder methods as deprecated
- Update documentation to reflect new APIs
BREAKING CHANGE: The old builder patterns using McpClient.using() and McpServer.using()
are now deprecated in favor of new sync() and async() builders that provide
better type safety and clearer sync/async separation. Follow the migration guide.
Resolves#48
Signed-off-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>
Co-authored-by: Christian Tzolov <ctzolov@vmware.com>
Introduces a new Server-Sent Events (SSE) Server transport implementation
based on the Servlet API that enables MCP integration with any Java HTTP
server application supporting Servlets.
This implementation complements the existing WebFlux and WebMvc transports
by providing a generic Servlet-based option that works with any Java web
server, not just Spring applications.
Key changes:
- Add HttpServletSseServerTransport with async Servlet 6.0 support
- Add integration tests with embedded Tomcat
- Add servlet dependencies with externalized versions:
- jakarta.servlet-api 6.1.0 (provided)
- tomcat-embed-core 11.0.2 (test)
- tomcat-embed-websocket 11.0.2 (test)
Resolves#61
Split the transport implementations into dedicated modules to improve modularity
and reduce core dependencies.
Added shared test module for common test utilities.
Key changes:
- Create mcp-transport/mcp-webflux-sse-transport module
- Move SseClientTransport → WebFluxSseClientTransport
- Move SseServerTransport → WebFluxSseServerTransport
- Move related tests and utilities
- Create mcp-transport/mcp-webmvc-sse-transport module
- Add new WebMvcSseServerTransport implementation
- Add corresponding tests and integration tests
- Add framework-independent SSE client implementations to core module
- Add FlowSseClient using java.net.http
- Add HttpClientSseClientTransport using java.net.http
- Keep StdioClientTransport/StdioServerTransport in core (no external deps)
- Create mcp-test module for shared test infrastructure
- Move abstract test base classes
- Move shared test utilities and mocks
- Update test dependencies
The modular approach allows users to choose between:
- Framework-specific implementations (WebFlux/WebMVC)
- Pure Java implementations (java.net.http)
- Basic implementations (STDIO)
Add breaking changes readme: 0.5.0-BREAKING-CHANGES.md
Resolves#54
