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

Class A2ARequest<T>

java.lang.Object

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

Type Parameters:

T - the type of the params object for this request

All Implemented Interfaces:

A2AMessage

Direct Known Subclasses:

NonStreamingJSONRPCRequest, StreamingJSONRPCRequest

public abstract sealed class A2ARequest<T>
extends Object
implements A2AMessage
permits NonStreamingJSONRPCRequest<T>, StreamingJSONRPCRequest<T>

Base class for JSON-RPC 2.0 requests in the A2A Protocol.

This sealed class represents a JSON-RPC 2.0 request message with parameterized support for different request parameter types. It enforces the JSON-RPC 2.0 specification requirements while providing type safety through generic parameters.

A JSON-RPC request consists of:

• jsonrpc - The protocol version (always "2.0")
• method - The name of the method to invoke
• params - Method parameters (optional, type varies by method)
• id - Correlation identifier for matching with responses (optional for notifications)

This class is sealed to ensure only NonStreamingJSONRPCRequest and StreamingJSONRPCRequest can extend it, providing compile-time guarantees about request types.

See Also:

• NonStreamingJSONRPCRequest
• StreamingJSONRPCRequest
• JSON-RPC 2.0 Specification
• A2A Protocol Specification

Field Summary

Fields

Modifier and Type	Field	Description
protected Object	id	The request identifier.
protected String	jsonrpc	The JSON-RPC protocol version.
protected String	method	The method name to invoke.
protected T	params	The method parameters.

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

JSONRPC_VERSION

Constructor Summary

Constructors

Constructor	Description
A2ARequest()	Default constructor for JSON deserialization.

Method Summary

Modifier and Type	Method	Description
Object	getId()	Gets the request/response correlation identifier.
String	getJsonrpc()	Gets the JSON-RPC version for this message.
String	getMethod()	Gets the name of the method to be invoked.
T	getParams()	Gets the parameters to be passed to the method.
protected void	validateAndSetJsonParameters(String jsonrpc, String method, Object id, T params, boolean paramsIsRequired)	Validates and sets JSON-RPC parameters.

Methods inherited from class java.lang.Object

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

Field Details

jsonrpc

protected String jsonrpc

The JSON-RPC protocol version.

id

protected Object id

The request identifier.

method

protected String method

The method name to invoke.

params

protected T params

The method parameters.

Constructor Details

A2ARequest

public A2ARequest()

Default constructor for JSON deserialization.

Method Details

getJsonrpc

public String getJsonrpc()

Gets the JSON-RPC version for this message.

According to the JSON-RPC 2.0 specification, this must be exactly "2.0".

Specified by:

getJsonrpc in interface A2AMessage

Returns:

the JSON-RPC version string, always "2.0"

getId

public Object getId()

Gets the request/response correlation identifier.

The ID is used to match responses with their corresponding requests. It may be a String, Integer, or null for notification-style requests that do not expect a response.

Specified by:

getId in interface A2AMessage

Returns:

the correlation ID, or null for notifications

getMethod

public String getMethod()

Gets the name of the method to be invoked.

Returns:

the method name

getParams

public T getParams()

Gets the parameters to be passed to the method.

Returns:

the method parameters, or null if none

validateAndSetJsonParameters

protected void validateAndSetJsonParameters(String jsonrpc,
 String method,
 Object id,
 T params,
 boolean paramsIsRequired)

Validates and sets JSON-RPC parameters.

Parameters:

jsonrpc - the JSON-RPC version

method - the method name

id - the request ID

params - the parameters

paramsIsRequired - whether parameters are required