Sample Async JAX-RS

This sample contains a few variations to illustrate how to use async request processing in JAX-RS 2.0 applications. It is organized around a generic Item, that is manipulated by an ItemService that happens to take a long time (it sleeps for a few seconds). Each variation copes with this slow service in a different way, to illustrate how JAX-RS Async requests work and how Concurrency Utilities and EJBs can be used to offload work to other threads while keeping the EE container happy.

Items: ItemsResource uses the ItemService to list, add, and fetch items, in the usual (synchronous) way.
Async Items: ItemsAsyncResource uses the @Suspended annotation with the AsyncResponse parameter, however, it is still essentially synchronous, as the work is not offloaded to a different thread.
Async EJB Items: ItemsEJBResource defines a stateless EJB, which allows work offloading with the addition of the @Asynchronous annotation.
Async Items with Executor: ItemsExecutorResource looks up the ManagedExecutorService defined by EE7 Concurrency Utilities in JNDI. Work for the request is then submitted to the executor and resumed later.
Async Items with CDI-provided Executor: ItemsCDIExecutorResource uses the ManagedExecutorService injected as an @Resource.

AsyncResponse objects can be configured to handle timeouts. There are two examples showing that:

Async with CDI-provided Executor and Timeout: ItemsCDIExecutorResourceTimeout sets a timeout, and registers a timeout handler, a connection callback, and a completion callback. Work is queued to a separate thread via a CDI-injected ManagedExecutorService.
Async EJB Items with Timeout: ItemsEJBResourceTimeout does the same as the previous example, but uses an asynchronous Stateless EJB instead.

Maven

Running in Eclipse with Maven

Clone this project and import into Eclipse as an 'Existing Maven Project'.
Right-click the project and select Run As > Run on Server.
You should see the following in the console: Application sample.spring started in XX.XX seconds.

Running with Maven command-line

This project can be built with Apache Maven. The project uses Liberty Maven Plug-in to automatically download and install the Liberty Java EE 7 Full Platform runtime from Maven Central. Liberty Maven Plug-in is also used to create, configure, and run the application on the Liberty server.

Use the following steps to run the application with Maven:

Execute the full Maven build. The Liberty Maven Plug-in will download and install the Liberty runtime and create the server.
```
$ mvn clean install
```
To run the server with the Spring application execute:
```
$ mvn liberty:run-server
```

Gradle

Running in Eclipse with Gradle

Go to Help > Eclipse Marketplace > Install Buildship Gradle Integration 2.0.
Clone this project and import into Eclipse as an 'Existing Gradle Project'.
Go to Window > Show View > Other > Gradle Executions & Gradle Tasks.
Go to Gradle Tasks view and run clean in build folder, then build in build folder, then libertyStart in liberty folder.
You should see the following in the console: Application sample.spring started in XX.XX seconds.

Running with Gradle command-line

This project can be built with Gradle. The project uses Liberty Gradle Plug-in to automatically download and install Liberty with Java EE 7 Full Platform runtime from Maven Central. Liberty Gradle Plug-in is also used to create, configure, and run the application on the Liberty server.

Use the following steps to run the application with Gradle:

Execute full Gradle build. This will cause Liberty Gradle Plug-in to download and install Liberty profile server.
```
$ gradle clean build
```
To run the server with the Spring application execute:
```
$ gradle libertyStart
```
To stop the server with the Spring application execute:
```
$ gradle libertyStop
```

In your browser, enter the URL for the application: http://localhost:9080/jaxrs-async/ (where port 9080 assumes the httpEndpoint provided in the sample server.xml has not been modified). In your browser, you should see the phone book displayed.

Notice

License

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

dblitza/sample.async.jaxrs