Class McpOperationHandler

java.lang.Object

dev.langchain4j.mcp.client.transport.McpOperationHandler

public class McpOperationHandler
extends Object

Handles incoming messages from the MCP server.

A transport calls onMessage(String) for every message it receives, and expectResponse(Long, java.util.concurrent.CompletableFuture) before sending a request, to register the id whose response it is waiting for.

The handle and startOperation methods do the same through Jackson's JsonNode and are deprecated.

Constructor Summary

Constructors

Constructor

Description

McpOperationHandler(Map<Long, CompletableFuture<String>> pendingOperations, Supplier<List<McpRoot>> roots, McpTransport transport, Consumer<McpLogMessage> logMessageConsumer, Runnable onToolListUpdate, Runnable onResourceListUpdate, Runnable onPromptListUpdate, Consumer<String> onResourceUpdate, McpProgressHandler progressHandler, Runnable onServerPing, Runnable onServerRootsList, BiConsumer<Long,String> onServerCancelled, BiConsumer<Long, Map<String,Object>> onSubscriptionAcknowledged)

Method Summary

Modifier and Type	Method	Description
void	cancelAllPendingOperations(String reason)
void	expectResponse(Long id, CompletableFuture<String> future)	Registers a client-initiated request whose response is awaited; the future is completed with the response as unparsed JSON text.
void	handle(com.fasterxml.jackson.databind.JsonNode message)	Deprecated, for removal: This API element is subject to removal in a future version. use onMessage(String) instead, which does not expose Jackson types.
void	onMessage(String json)	Handles an inbound message from the server, taken exactly as it arrived on the wire, so that a transport does not have to parse it first.
void	startOperation(Long id, CompletableFuture<com.fasterxml.jackson.databind.JsonNode> future)	Deprecated, for removal: This API element is subject to removal in a future version. use expectResponse(Long, CompletableFuture) instead, which does not expose Jackson types.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

McpOperationHandler

public McpOperationHandler(Map<Long, CompletableFuture<String>> pendingOperations,
 Supplier<List<McpRoot>> roots,
 McpTransport transport,
 Consumer<McpLogMessage> logMessageConsumer,
 Runnable onToolListUpdate,
 Runnable onResourceListUpdate,
 Runnable onPromptListUpdate,
 Consumer<String> onResourceUpdate,
 McpProgressHandler progressHandler,
 Runnable onServerPing,
 Runnable onServerRootsList,
 BiConsumer<Long,String> onServerCancelled,
 BiConsumer<Long, Map<String,Object>> onSubscriptionAcknowledged)

Method Details

handle

@Deprecated(since="1.20.0",
            forRemoval=true)
public void handle(com.fasterxml.jackson.databind.JsonNode message)

Deprecated, for removal: This API element is subject to removal in a future version.

use onMessage(String) instead, which does not expose Jackson types.

Handles an inbound message from the server.

onMessage

public void onMessage(String json)

Handles an inbound message from the server, taken exactly as it arrived on the wire, so that a transport does not have to parse it first.

Valid JSON that is not a JSON-RPC object - a batch array, a scalar, a bare null - is ignored. Text that is not valid JSON at all throws, so that the transport can decide: fail the pending operation, or log and keep reading.

Throws:

IllegalArgumentException - if the message is not valid JSON, or JsonException from a codec that reports the typed exceptions.

startOperation

@Deprecated(since="1.20.0",
            forRemoval=true)
public void startOperation(Long id,
 CompletableFuture<com.fasterxml.jackson.databind.JsonNode> future)

Deprecated, for removal: This API element is subject to removal in a future version.

use expectResponse(Long, CompletableFuture) instead, which does not expose Jackson types.

Registers a client-initiated request whose response is awaited.

expectResponse

public void expectResponse(Long id,
 CompletableFuture<String> future)

Registers a client-initiated request whose response is awaited; the future is completed with the response as unparsed JSON text.

cancelAllPendingOperations

public void cancelAllPendingOperations(String reason)