docs/images/java/class-diagrams.puml

@startuml Core Components

' Core Interfaces
interface McpTransport {
  +Mono<Void> connect(Function<Mono<JSONRPCMessage>, Mono<JSONRPCMessage>> handler)
  +Mono<Void> sendMessage(JSONRPCMessage message)
  +void close()
  +Mono<Void> closeGracefully()
  +<T> T unmarshalFrom(Object data, TypeReference<T> typeRef)
}

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()
  +void close()
}

' Core Implementation Classes
class DefaultMcpSession {
  +interface RequestHandler
  +interface NotificationHandler
}

' Client Classes
class McpClient {
  +{static} Builder using(ClientMcpTransport transport)
}

class McpAsyncClient {
  +Mono<InitializeResult> initialize()
  +ServerCapabilities getServerCapabilities()
  +Implementation getServerInfo()
  +ClientCapabilities getClientCapabilities()
  +Implementation getClientInfo()
  +void close()
  +Mono<Void> closeGracefully()
  +Mono<Object> ping()
  +Mono<Void> addRoot(Root root)
  +Mono<Void> removeRoot(String rootUri)
  +Mono<Void> rootsListChangedNotification()
  +Mono<CallToolResult> callTool(CallToolRequest request)
  +Mono<ListToolsResult> listTools()
  +Mono<ListResourcesResult> listResources()
  +Mono<ReadResourceResult> readResource(ReadResourceRequest request)
  +Mono<ListResourceTemplatesResult> listResourceTemplates()
  +Mono<Void> subscribeResource(SubscribeRequest request)
  +Mono<Void> unsubscribeResource(UnsubscribeRequest request)
  +Mono<ListPromptsResult> listPrompts()
  +Mono<GetPromptResult> getPrompt(GetPromptRequest request)
  +Mono<Void> setLoggingLevel(LoggingLevel level)
}

class McpSyncClient {
  +InitializeResult initialize()
  +ServerCapabilities getServerCapabilities()
  +Implementation getServerInfo()
  +ClientCapabilities getClientCapabilities()
  +Implementation getClientInfo()
  +void close()
  +boolean closeGracefully()
  +Object ping()
  +void addRoot(Root root)
  +void removeRoot(String rootUri)
  +void rootsListChangedNotification()
  +CallToolResult callTool(CallToolRequest request)
  +ListToolsResult listTools()
  +ListResourcesResult listResources()
  +ReadResourceResult readResource(ReadResourceRequest request)
  +ListResourceTemplatesResult listResourceTemplates()
  +void subscribeResource(SubscribeRequest request)
  +void unsubscribeResource(UnsubscribeRequest request)
  +ListPromptsResult listPrompts()
  +GetPromptResult getPrompt(GetPromptRequest request)
  +void setLoggingLevel(LoggingLevel level)
}

' Server Classes
class McpServer {
  +{static} Builder using(ServerMcpTransport transport)
}

class McpAsyncServer {
  
  +ServerCapabilities getServerCapabilities()
  +Implementation getServerInfo()
  +ClientCapabilities getClientCapabilities()
  +Implementation getClientInfo()
  +void close()
  +Mono<Void> closeGracefully()
  
  ' Tool Management
  +Mono<Void> addTool(ToolRegistration toolRegistration)
  +Mono<Void> removeTool(String toolName)
  +Mono<Void> notifyToolsListChanged()
  
  ' Resource Management
  +Mono<Void> addResource(ResourceRegistration resourceHandler)
  +Mono<Void> removeResource(String resourceUri)
  +Mono<Void> notifyResourcesListChanged()
  
  ' Prompt Management
  +Mono<Void> addPrompt(PromptRegistration promptRegistration)
  +Mono<Void> removePrompt(String promptName)
  +Mono<Void> notifyPromptsListChanged()
  
  ' Logging
  +Mono<Void> loggingNotification(LoggingMessageNotification notification)
  
  ' Sampling
  +Mono<CreateMessageResult> createMessage(CreateMessageRequest request)
}

class McpSyncServer {
  +McpAsyncServer getAsyncServer()
  
  +ServerCapabilities getServerCapabilities()
  +Implementation getServerInfo()
  +ClientCapabilities getClientCapabilities()
  +Implementation getClientInfo()
  +void close()
  +void closeGracefully()
  
  ' Tool Management
  +void addTool(ToolRegistration toolHandler)
  +void removeTool(String toolName)
  +void notifyToolsListChanged()
  
  ' Resource Management
  +void addResource(ResourceRegistration resourceHandler)
  +void removeResource(String resourceUri)
  +void notifyResourcesListChanged()
  
  ' Prompt Management
  +void addPrompt(PromptRegistration promptRegistration)
  +void removePrompt(String promptName)
  +void notifyPromptsListChanged()
  
  ' Logging
  +void loggingNotification(LoggingMessageNotification notification)
  
  ' Sampling
  +CreateMessageResult createMessage(CreateMessageRequest request)
}

' Transport Implementations
class StdioClientTransport implements ClientMcpTransport {  
  +void setErrorHandler(Consumer<String> errorHandler)
  +Sinks.Many<String> getErrorSink()
}

class StdioServerTransport implements ServerMcpTransport {
}


class HttpServletSseServerTransport implements ServerMcpTransport {
}


class HttpClientSseClientTransport implements ClientMcpTransport {  
}


class WebFluxSseClientTransport implements ClientMcpTransport {
}


class WebFluxSseServerTransport implements ServerMcpTransport {
  +RouterFunction<?> getRouterFunction()
}

class WebMvcSseServerTransport implements ServerMcpTransport {
  +RouterFunction<?> getRouterFunction()
}


' Schema and Error Classes
class McpSchema {
  +class ErrorCodes
  +interface Request
  +interface JSONRPCMessage
  +interface ResourceContents
  +interface Content
  +interface ServerCapabilities
  +{static} JSONRPCMessage deserializeJsonRpcMessage()
}

class McpError {
}

' Relationships
McpTransport <|.. ClientMcpTransport
McpTransport <|.. ServerMcpTransport

McpSession <|.. DefaultMcpSession
DefaultMcpSession --o McpAsyncClient
DefaultMcpSession --o McpAsyncServer

McpClient ..> McpAsyncClient : creates
McpClient ..> McpSyncClient : creates
McpSyncClient --> McpAsyncClient : delegates to

McpServer ..> McpAsyncServer : creates
McpServer ..> McpSyncServer : creates
McpSyncServer o-- McpAsyncServer

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 ListToolsRequest
  class ListResourcesRequest
  class ReadResourceRequest
  class ListResourceTemplatesRequest
  class ListPromptsRequest
  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
  
  interface Annotated {
    +Annotations annotations()
  }
  
  interface PromptOrResourceReference {
    +String type()
  }
  
  class PromptReference
  class ResourceReference
}

JSONRPCMessage <|.. Request
Request <|.. InitializeRequest
Request <|.. CallToolRequest
Request <|.. ListToolsRequest
Request <|.. ListResourcesRequest
Request <|.. ReadResourceRequest
Request <|.. ListResourceTemplatesRequest
Request <|.. ListPromptsRequest
Request <|.. GetPromptRequest

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

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

PromptOrResourceReference <|.. PromptReference
PromptOrResourceReference <|.. ResourceReference

@enduml