Package com.xebialabs.xlrelease.a2a.client

Class A2aProtocolClient

java.lang.Object
com.xebialabs.xlrelease.a2a.client.A2aProtocolClient
All Implemented Interfaces:
com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension, com.xebialabs.xlrelease.osgi.api.spring.HostExtensionPoint
public class A2aProtocolClient extends Object implements com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension
The host's built-in A2A wire layer: Agent Card resolution plus the JSON-RPC 2.0 binding over HTTPS/HTTP, on the JDK HttpClient, speaking A2A 1.0.

Implements A2aTransportExtension so the gateway treats it exactly like a bundle-contributed transport — it is simply the fallback used when no transport bundle is installed. Nothing above this class touches HTTP or the JSON-RPC envelope; nothing in this class knows about policy — allowlisting and feature checks belong to the gateway.

1.0, not 0.3. The two differ in every shape this class touches — the card carries supportedInterfaces instead of a top-level url, methods are SendMessage / GetTask / CancelTask instead of message/send / tasks/get / tasks/cancel, a SendMessage result is a task / message oneof instead of an inlined task, roles are ROLE_USER / ROLE_AGENT, states are TASK_STATE_*, and text parts have lost their kind discriminator. The version is negotiated by the A2A-Version header, and a request that omits it is read as 0.3 — a spec-compliant 1.0 agent then rejects the call before it reads the body, so that header is mandatory rather than informational.

Strict out, lenient in. Requests are built as a2a-java-sdk-spec types and written by the SDK's own mapper, because 1.0 discriminates its oneofs by member name and only that mapper writes them properly — sending the wrong shape is the bug this class exists to stop making. Responses are read as a JSON tree instead. The SDK's records validate in their compact constructors, so a Task whose status.state this SDK revision does not recognise fails to construct at all; reading leniently keeps the documented behaviour that an unknown state degrades to A2aTaskState.UNKNOWN and the caller keeps polling, rather than a remote agent on a newer spec revision breaking every task in Release. Only five fields are taken from a response, so there is nothing to gain from typing that side and a robustness property to lose.

The full SDK (with vertx, gRPC and CDI behind it) belongs in a transport bundle, where OSGi classloader isolation keeps its dependency stack off the host classpath — that is what test-plugins/a2a-sdk-transport-plugin is for. Only the spec and JSON-RPC-envelope modules are on this classpath: types and a Gson mapper, nothing else.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    AGENT_CARD_PATH
    Well-known Agent Card path per the A2A specification.

  • Constructor Summary

    Constructors
    Constructor
    Description
    A2aProtocolClient()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    com.xebialabs.xlrelease.a2a.api.views.A2aTaskView
    cancelTask(String endpointUrl, String taskId, String bearerToken)
     
    com.xebialabs.xlrelease.a2a.api.views.A2aAgentIdentity
    fetchAgentCard(String agentCardUrl, String bearerToken)
     
    com.xebialabs.xlrelease.a2a.api.views.A2aTaskView
    getTask(String endpointUrl, String taskId, String bearerToken)
     
    com.xebialabs.xlrelease.a2a.api.views.A2aSendResult
    sendMessage(String endpointUrl, com.xebialabs.xlrelease.a2a.api.views.A2aSendRequest request)
     
    com.xebialabs.xlrelease.a2a.api.views.A2aSendResult
    sendMessage(String endpointUrl, com.xebialabs.xlrelease.a2a.api.views.A2aSendRequest request, com.xebialabs.xlrelease.a2a.api.views.A2aCallback callback)
     

    Methods inherited from class java.lang.Object

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

  • Field Details

    • AGENT_CARD_PATH

      public static final String AGENT_CARD_PATH
      Well-known Agent Card path per the A2A specification.
      See Also:

  • Constructor Details

    • A2aProtocolClient

      public A2aProtocolClient()

  • Method Details

    • fetchAgentCard

      public com.xebialabs.xlrelease.a2a.api.views.A2aAgentIdentity fetchAgentCard(String agentCardUrl, String bearerToken)
      Specified by:
      fetchAgentCard in interface com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension

    • sendMessage

      public com.xebialabs.xlrelease.a2a.api.views.A2aSendResult sendMessage(String endpointUrl, com.xebialabs.xlrelease.a2a.api.views.A2aSendRequest request)
      Specified by:
      sendMessage in interface com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension

    • sendMessage

      public com.xebialabs.xlrelease.a2a.api.views.A2aSendResult sendMessage(String endpointUrl, com.xebialabs.xlrelease.a2a.api.views.A2aSendRequest request, com.xebialabs.xlrelease.a2a.api.views.A2aCallback callback)
      Specified by:
      sendMessage in interface com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension

    • getTask

      public com.xebialabs.xlrelease.a2a.api.views.A2aTaskView getTask(String endpointUrl, String taskId, String bearerToken)
      Specified by:
      getTask in interface com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension

    • cancelTask

      public com.xebialabs.xlrelease.a2a.api.views.A2aTaskView cancelTask(String endpointUrl, String taskId, String bearerToken)
      Specified by:
      cancelTask in interface com.xebialabs.xlrelease.osgi.api.a2a.A2aTransportExtension