java-sdk/docs/class-diagrams.puml

@startuml Core Components

interface McpTransport {
  +Mono<Void> connect(Function<Mono<JSONRPCMessage>, 
                       Mono<JSONRPCMessage>> handler)
  +Mono<Void> sendMessage()
  +void close()
  +Mono<Void> closeGracefully()
}

interface McpSession {
  +<T> Mono<T> sendRequest(String method, Object requestParams, TypeReference<T> typeRef)
  +Mono<Void> sendNotification(String method, Map<String, Object> params)
  +Mono<Void> closeGracefully()
  +close()
}

class DefaultMcpSession {
  -McpTransport transport
  -ObjectMapper objectMapper
}

class McpClient {
  +{static} async()
  +{static} sync()
}

class McpAsyncClient {
  +Mono<InitializeResult> initialize()
  +Mono<CallToolResult> callTool()
  +Mono<ListToolsResult> listTools()
  +Mono<ListResourcesResult> listResources()
  +Mono<ReadResourceResult> readResource()
  +Mono<ListPromptsResult> listPrompts()
  +Mono<GetPromptResult> getPrompt()
}

class McpSyncClient {
  +InitializeResult initialize()
  +CallToolResult callTool()
  +ListToolsResult listTools()
  +ListResourcesResult listResources()
  +ReadResourceResult readResource()
  +ListPromptsResult listPrompts()
  +GetPromptResult getPrompt()
}

class StdioClientTransport {
  -Process serverProcess
  -ServerParameters parameters
}

class SseClientTransport {
  -WebClient webClient
}

class McpSchema {
  +class ErrorCodes
  +interface Request
  +interface JSONRPCMessage
  +interface ResourceContents
  +interface Content
}

class McpError {
  -int code
  -String message
}

McpTransport <|-- StdioClientTransport
McpTransport <|-- SseClientTransport
McpSession <|-- DefaultMcpSession
DefaultMcpSession --o McpAsyncClient
McpClient ..> McpAsyncClient : creates
McpClient ..> McpSyncClient : creates
McpSyncClient o-- McpAsyncClient
DefaultMcpSession o-- McpTransport
McpSchema <.. McpSession : uses
McpError ..> McpSession : throws

@enduml

@startuml Message Flow

package "MCP Schema" {
  interface JSONRPCMessage {
    +String jsonrpc()
  }
  
  interface Request {
  }
  
  class InitializeRequest
  class CallToolRequest
  class CreateMessageRequest
  class CompleteRequest
  class GetPromptRequest
}

package "Resource Types" {
  interface ResourceContents {
    +String uri()
    +String mimeType()
  }
  
  class TextResourceContents
  class BlobResourceContents
  
  interface Content {
    +String type()
  }
  
  class TextContent
  class ImageContent
  class EmbeddedResource
}

JSONRPCMessage <|.. Request
Request <|.. InitializeRequest
Request <|.. CallToolRequest
Request <|.. CreateMessageRequest
Request <|.. CompleteRequest
Request <|.. GetPromptRequest

ResourceContents <|.. TextResourceContents
ResourceContents <|.. BlobResourceContents

Content <|.. TextContent
Content <|.. ImageContent
Content <|.. EmbeddedResource

@enduml