What is it?

Jclient-common allows to make asynchronous HTTP calls to remote services in Java applications.

Heavy-lifting is performed using Async Http Client, while the library provides user friendly interface that hides unnecessary details.

Requirements

Java 11 is a requirement to build and use this library.

Additionally, if you want to use method JClientBase.jerseyUrl(), you have to provide one of the following libraries:

• javax.ws.rs:jsr311-api (jersey v.1)
• javax.ws.rs:javax.ws.rs-api (jersey v.2)

depending on what version of Jersey you use in your application.

Client code that uses this library is usually stored together with server code that it calls, in separate maven module.

Sample code:

HttpClientFactory http = ...;
JAXBContext jaxb = JAXBContext.newInstance(Banners.class);
Request request = new RequestBuilder("GET").setUrl("http://myservice/banners").addQueryParam("places", "1,2,3").build();
CompletableFuture<Banners> bannersFuture = http.with(request).expectXml(jaxb, Banners.class).request();

Creating a client

HttpClientFactoryBuilder is a builder that provides convenient way to create an instance of HttpClientFactory:

HttpClientFactory http = new HttpClientFactoryBuilder(new SingletonStorage<>(() -> new HttpClientContext(Map.of(), Map.of(), List.of())), List.of())
    .withProperties(jClientProperties)
    .withRequestStrategy(new DefaultRequestStrategy())
    .withCallbackExecutor(Runnable::run)
    .withHostsWithSession(hostsWithSession)
    .withUserAgent("my service")
    .build();

Example of jclient properties:

jclient.connectionTimeoutMs=1100
jclient.requestTimeoutMs=2100
jclient.readTimeoutMs=-1
jclient.userAgent=hh-xmlback
jclient.hostsWithSession=http://localhost

Notice that readTimeoutMs is set to -1, which means to ignore this setting.

This is because in case when readTimeout < requestTimeout, readTimeout will be executed earlier than requestTimeout, so if requestTimeout is sufficiently large (e.g. for slow requests) it will not work as expected.

Load balancing

See balancing readme