New interface types
The new API in Habari Client libraries 6.0 is based on three new interfaces which reduce the amount of client code:
- IMQContext
- IMQProducer
- IMQConsumer
IMQContext interface
A IMQContext object encapsulates both the IConnection and the ISession object of the classic API. The connection factory interface contains new methods to create IMQContext objects:
function CreateContext: IMQContext; overload;
function CreateContext(const AcknowledgeMode:
TAcknowledgementMode): IMQContext; overload;
function CreateContext(const Username, Password: string):
IMQContext; overload;
function CreateContext(const Username, Password: string;
const AcknowledgeMode: TAcknowledgementMode):
IMQContext; overload;
The IMQContext provides methods to create messages, producer and consumer objects, destinations (queues, topics, temporary queues, temporary topics, durable subscribers and so forth), and for transaction control (commit, rollback).
IMQProducer interface
A IMQProducer object provides methods to produce and send messages to the broker. As a shortcut, a method allows to send text or bytes messages without creating ITextMessage or IBytesMessage object by providing the text or bytes as a parameter.
function Send(const Destination: IDestination;
const Body: string): IMQProducer; overload;
function Send(const Destination: IDestination;
const AMessage: IMessage): IMQProducer; overload;
...
IMQConsumer interface
A IMQConsumer object provides methods to consume messages from the broker.
The following example is taken from the unit tests. It uses the new API to create and send a text message to a broker queue destination, and then receives the message from this queue.
Source code example
procedure TNewApiTests.TestSendMessage;
var
Context: IMQContext;
Destination: IQueue;
Producer: IMQProducer;
Consumer: IMQConsumer;
TextMessage: ITextMessage;
begin
Context := Factory.CreateContext;
Destination := Context.CreateQueue(GetQueueName);
Producer := Context.CreateProducer;
Producer.Send(Destination, 'Hello World');
Consumer := Context.CreateConsumer(Destination);
TextMessage := Consumer.Receive(2500) as ITextMessage;
CheckEquals('Hello World', TextMessage.Text);
Context.Close;
end;
Download
A snapshot of the new 6.0 release is available in the Habari Client for ActiveMQ and the Habari Client for RabbitMQ download areas:
- https://www.habarisoft.com/habari_activemq/download/release/habari-activemq-6.0-SNAPSHOT.installer.exe
- https://www.habarisoft.com/habari_rabbitmq/download/release/habari-rabbitmq-6.0-SNAPSHOT.installer.exe
General availability
Release 6.0 is planned for Q4/2018. Users of the 5.x releases are encouraged to download and test the 6.0 snapshot. Feedback is always welcome.
About Habari Client libraries
Habari Client libraries enable Object Pascal applications to take advantage of message broker / message queue technology – which is distributed, loosely coupled, reliable and asynchronous – to build integrated systems, using peer-to-peer and publish-subscribe communication models.
