Joseph DohertyJava Client
The Java client workspace contains the MXAccess Gateway client library, generated protobuf/gRPC bindings, a Picocli test CLI project, and JUnit tests.
Layout
clients/java/
settings.gradle
build.gradle
src/main/generated/
mxgateway-client/
mxgateway-cli/
mxgateway-client generates Java protobuf and gRPC sources from
../../src/MxGateway.Contracts/Protos. The Gradle protobuf plugin writes those
generated sources under src/main/generated, which matches the client proto
manifest in ../proto/proto-inputs.json. Do not edit generated files by hand.
mxgateway-client exposes MxGatewayClientOptions, MxGatewayClient,
MxGatewaySession, value/status helpers, typed gateway exceptions, raw
generated stubs, and generated protobuf messages for parity tests.
mxgateway-cli depends on mxgateway-client and provides the mxgw-java
application entry point. The CLI supports version, session, command, event
streaming, write, and smoke-test commands with deterministic JSON output.
Client Usage
Create a client with explicit transport and auth options:
MxGatewayClientOptions options = MxGatewayClientOptions.builder()
.endpoint("localhost:5000")
.apiKey(System.getenv("MXGATEWAY_API_KEY"))
.plaintext(true)
.build();
try (MxGatewayClient client = MxGatewayClient.connect(options);
MxGatewaySession session = client.openSession("java-client")) {
int serverHandle = session.register("java-client");
int itemHandle = session.addItem(serverHandle, "TestObject.TestInt");
session.advise(serverHandle, itemHandle);
session.write(serverHandle, itemHandle, MxValues.int32Value(123), 0);
}
Use rawBlockingStub, rawFutureStub, rawAsyncStub, openSessionRaw,
closeSessionRaw, invoke, and raw session helper methods when tests need the
underlying protobuf messages. MxGatewayCommandException and
MxAccessException preserve the raw MxCommandReply when the gateway returns a
data-bearing MXAccess failure.
MxEventStream implements Iterator<MxEvent> and AutoCloseable. Closing it
cancels the underlying gRPC stream. Canceling or timing out a Java client call
only stops the client from waiting; it does not abort an in-flight MXAccess COM
call on the worker STA.
CLI Usage
Run the CLI through Gradle:
gradle :mxgateway-cli:run --args="version --json"
gradle :mxgateway-cli:run --args="open-session --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --client-session-name java-cli --json"
gradle :mxgateway-cli:run --args="register --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --session-id <id> --client-name java-cli --json"
gradle :mxgateway-cli:run --args="add-item --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --session-id <id> --server-handle 1 --item TestObject.TestInt --json"
gradle :mxgateway-cli:run --args="advise --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --session-id <id> --server-handle 1 --item-handle 1 --json"
gradle :mxgateway-cli:run --args="write --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --session-id <id> --server-handle 1 --item-handle 1 --type int32 --value 123 --json"
gradle :mxgateway-cli:run --args="stream-events --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --session-id <id> --limit 1 --json"
gradle :mxgateway-cli:run --args="smoke --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --item TestObject.TestInt --json"
The CLI accepts --api-key, --api-key-env, --plaintext, --ca-file,
--server-name-override, --timeout, and --json on gateway commands. JSON
output redacts API keys.
Build And Test
Run the Java checks from clients/java:
gradle test
The build uses the Java 21 Gradle toolchain, compiles generated protobuf/gRPC code, and runs JUnit 5 tests for the client wrapper, shared behavior fixtures, in-process gRPC behavior, stream cancellation, and CLI parser/output behavior.