Transport

Overview

The transport layer abstracts HTTP communication from the session logic. The session builds runCommandJSON payloads and delegates HTTP delivery to a transport implementation. This separation enables testing the entire command pipeline without an MQ server by injecting a mock transport.

MqRestTransport

The transport interface defines a single method for posting JSON payloads:

public interface MqRestTransport {
    TransportResponse postJson(
        String url,
        Map<String, Object> payload,
        Map<String, String> headers,
        Duration timeout,
        boolean verifyTls
    );
}

Parameter	Description
url	Fully-qualified endpoint URL
payload	The runCommandJSON request body
headers	Authentication, CSRF token, and optional gateway headers
timeout	Per-request timeout duration
verifyTls	Whether to verify server certificates

Throws MqRestTransportException on network failures.

HttpClientTransport

The default transport implementation using java.net.http.HttpClient (JDK built-in, zero additional dependencies beyond Gson for JSON serialization):

// Default — verifies TLS certificates
var transport = new HttpClientTransport();

// Custom SSLContext for mTLS client certificate authentication
var transport = new HttpClientTransport(sslContext);

HttpClientTransport handles:

• HTTPS connections with configurable SSLContext
• Automatic TLS certificate verification (or disabled via verifyTls=false)
• Request timeouts via Duration
• JSON serialization/deserialization with Gson
• Custom HTTP headers
• Defensive header flattening per RFC 9110

TransportResponse

An immutable record containing the HTTP response data:

public record TransportResponse(
    int statusCode,
    String body,                   // never null (empty string if no body)
    Map<String, String> headers    // never null, unmodifiable
) {}

Custom transport

Implement MqRestTransport to provide custom HTTP behavior or for testing. Because the interface has a single method, a lambda works naturally:

// Mock transport for unit tests
MqRestTransport mockTransport = (url, payload, headers, timeout, verify) ->
    new TransportResponse(200, responseJson, Map.of());

var session = MqRestSession.builder()
    .host("localhost")
    .port(9443)
    .queueManager("QM1")
    .credentials(new LtpaAuth("admin", "passw0rd"))
    .transport(mockTransport)
    .build();

This pattern is used extensively in the library's own test suite to verify command payload construction, response parsing, and error handling without network access.