Struct A2AMethodRegistry 

pub struct A2AMethodRegistry { /* private fields */ }

A2A Method Registry

Central registry for A2A protocol methods and their handlers. Provides method registration, lookup, and validation functionality without any transport dependencies.

Design Principles

• Pure Domain Logic: No transport or infrastructure concerns
• JSON-RPC Foundation: All methods use JSON-RPC 2.0 message types
• Thread Safe: Can be safely shared across multiple threads
• Method Metadata: Rich metadata for discovery and documentation

Examples

use a2a_protocol_core::{A2AMethodRegistry, JsonRpcRequest, JsonRpcResponse, A2AError};
use serde_json::json;
use std::sync::Arc;

fn example() -> Result<(), A2AError> {
    let mut registry = A2AMethodRegistry::new();
     
    // Register a method handler
    registry.register_method(
        "ping",
        "Simple ping method",
        Arc::new(|request| {
            Ok(JsonRpcResponse::success(request.id, json!({"pong": true})))
        })
    );
     
    // Handle requests
    let request = JsonRpcRequest::new(json!("req-123"), "ping".to_string(), json!({}));
    let response = registry.handle_request(request)?;
    Ok(())
}

Implementations

impl A2AMethodRegistry

pub fn new() -> Self

Create a new empty registry

pub fn with_agent_card(agent_card: AgentCard) -> Self

Create a registry with agent card

pub fn set_agent_card(&mut self, agent_card: AgentCard)

Set the agent card for this registry

pub fn agent_card(&self) -> Option<&AgentCard>

Get the agent card

pub fn register_method( &mut self, method: impl Into<String>, description: impl Into<String>, handler: A2AMethodHandler, )

Register a method handler

Registers a handler function for JSON-RPC requests to the specified method.

Arguments

• method: Method name (e.g., “ping”, “process_data”)
• description: Human-readable description of the method
• handler: Function that handles requests for this method

pub fn register_method_with_metadata( &mut self, method: impl Into<String>, description: impl Into<String>, parameters: Option<Value>, returns: Option<Value>, handler: A2AMethodHandler, )

Register a method handler with metadata

Registers a method handler with detailed parameter and return type information.

pub fn register_notification( &mut self, method: impl Into<String>, description: impl Into<String>, handler: A2ANotificationHandler, )

Register a notification handler

Registers a handler function for JSON-RPC notifications (fire-and-forget).

Arguments

• method: Method name (e.g., “log.info”, “metric.counter”)
• description: Human-readable description of the notification
• handler: Function that handles notifications for this method

pub fn handle_request( &self, request: JsonRpcRequest, ) -> A2AResult<JsonRpcResponse>

Handle a JSON-RPC request

Looks up the method handler and executes it with the request.

Arguments

• request: The JSON-RPC 2.0 request to handle

Returns

• Ok(JsonRpcResponse): Success response from method handler
• Err(A2AError): Method not found or handler error

pub fn handle_notification( &self, notification: JsonRpcNotification, ) -> A2AResult<()>

Handle a JSON-RPC notification

Looks up the notification handler and executes it.

Arguments

• notification: The JSON-RPC 2.0 notification to handle

Returns

• Ok(()): Notification handled successfully
• Err(A2AError): Method not found or handler error

pub fn has_method(&self, method: &str) -> bool

Check if method is registered

pub fn has_notification(&self, method: &str) -> bool

Check if notification is registered

pub fn get_method_metadata(&self, method: &str) -> Option<&MethodMetadata>

Get method metadata

pub fn list_methods(&self) -> Vec<String>

List all registered methods

pub fn list_notifications(&self) -> Vec<String>

List all registered notifications

pub fn get_all_metadata(&self) -> &HashMap<String, MethodMetadata>

Get all method metadata

pub fn unregister_method(&mut self, method: &str) -> bool

Unregister a method

pub fn unregister_notification(&mut self, method: &str) -> bool

Unregister a notification

pub fn clear(&mut self)

Clear all registrations

pub fn stats(&self) -> RegistryStats

Get registry statistics

Trait Implementations

impl Default for A2AMethodRegistry

fn default() -> Self

Returns the “default value” for a type.