Package org.a2aproject.sdk.jsonrpc.common.wrappers

Class SubscribeToTaskRequest

java.lang.Object

org.a2aproject.sdk.jsonrpc.common.wrappers.A2ARequest<T>

org.a2aproject.sdk.jsonrpc.common.wrappers.StreamingJSONRPCRequest<TaskIdParams>

org.a2aproject.sdk.jsonrpc.common.wrappers.SubscribeToTaskRequest

All Implemented Interfaces:

A2AMessage

public final class SubscribeToTaskRequest
extends StreamingJSONRPCRequest<TaskIdParams>

JSON-RPC request to subscribe to an ongoing or completed task's event stream.

This request allows clients to reconnect to a task and receive its events, enabling recovery from disconnections or retrieval of missed updates. The agent will stream events for the task starting from its current state.

Resubscription is particularly useful for:

• Recovering from network interruptions without losing task context
• Multiple clients observing the same task
• Retrieving final results for completed tasks

This class implements the JSON-RPC SubscribeToTask method as specified in the A2A Protocol.

See Also:

• for the parameter structure
• for the types of events that can be streamed
• A2A Protocol Specification

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SubscribeToTaskRequest.Builder	Builder for constructing instances.

Field Summary

Fields inherited from class org.a2aproject.sdk.jsonrpc.common.wrappers.A2ARequest

id, jsonrpc, method, params

Fields inherited from interface org.a2aproject.sdk.jsonrpc.common.wrappers.A2AMessage

JSONRPC_VERSION

Constructor Summary

Constructors

Constructor	Description
SubscribeToTaskRequest(Object id, TaskIdParams params)	Constructs request with ID and parameters.
SubscribeToTaskRequest(String jsonrpc, Object id, TaskIdParams params)	Constructs request with all parameters.

Method Summary

Modifier and Type	Method	Description
static SubscribeToTaskRequest.Builder	builder()	Create a new Builder

Methods inherited from class org.a2aproject.sdk.jsonrpc.common.wrappers.A2ARequest

getId, getJsonrpc, getMethod, getParams, validateAndSetJsonParameters

Methods inherited from class java.lang.Object

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

Constructor Details

SubscribeToTaskRequest

public SubscribeToTaskRequest(String jsonrpc,
 Object id,
 TaskIdParams params)

Constructs request with all parameters.

Parameters:

jsonrpc - the JSON-RPC version

id - the request ID

params - the request parameters

SubscribeToTaskRequest

public SubscribeToTaskRequest(Object id,
 TaskIdParams params)

Constructs request with ID and parameters.

Parameters:

id - the request ID

params - the request parameters

Method Details

builder

public static SubscribeToTaskRequest.Builder builder()

Create a new Builder

Returns:

the builder