Package io.a2a.spec

Class UnsupportedOperationError

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

io.a2a.spec.A2AError

io.a2a.spec.A2AProtocolError

io.a2a.spec.UnsupportedOperationError

All Implemented Interfaces:

Event, Serializable

public class UnsupportedOperationError
extends A2AProtocolError

A2A Protocol error indicating that the requested operation is not supported by the agent.

This error is returned when a client attempts an operation that is valid according to the A2A Protocol but not implemented or enabled by the specific agent. This is distinct from MethodNotFoundError, which indicates an unknown JSON-RPC method.

Common scenarios:

• Calling streaming methods when AgentCapabilities.streaming() is false
• Attempting push notification operations when AgentCapabilities.pushNotifications() is false
• Using optional protocol features not implemented by the agent
• Agent-specific operations disabled by configuration

Corresponds to A2A-specific error code -32004.

Usage example:

 if (!agentCard.capabilities().streaming()) {
     throw new UnsupportedOperationError();
 }
 

See Also:

• for agent capability declarations
• for unknown method errors
• A2A Protocol Specification
• Serialized Form

Constructor Summary

Constructors

Constructor	Description
UnsupportedOperationError()	Constructs error with default message.
UnsupportedOperationError(@Nullable Integer code, @Nullable String message, @Nullable Object data)	Constructs error with all parameters.

Method Summary

Methods inherited from class io.a2a.spec.A2AProtocolError

getUrl

Methods inherited from class io.a2a.spec.A2AError

getCode, getData

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Constructor Details

UnsupportedOperationError

public UnsupportedOperationError(@Nullable Integer code,
 @Nullable String message,
 @Nullable Object data)

Constructs error with all parameters.

Parameters:

code - the error code (defaults to -32004 if null)

message - the error message (defaults to "This operation is not supported" if null)

data - additional error data (optional)

UnsupportedOperationError

public UnsupportedOperationError()

Constructs error with default message.