CompletionStageIssue

TempClient.java

import org.eclipse.microprofile.rest.client.annotation.RegisterProvider;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import java.util.List;
import java.util.concurrent.CompletionStage;

@RegisterRestClient(baseUri = "https://jsonplaceholder.typicode.com")
@RegisterProvider(ClientLoggingFilter.class)
@RegisterProvider(TempExceptionResponseMapper.class)
public interface TempClient {

	@GET
	@Path("/todos")
	@Produces(Constants.APPLICATION_JSON)
	CompletionStage<List<Todo>> getTodos() throws TempException;

}

TempExceptionResponseMapper.java

package momentum.retail.via_bff.client.responseexceptionmapper;

import momentum.retail.via_bff.domain.exception.TempException;
import org.apache.commons.lang3.StringUtils;
import org.eclipse.microprofile.rest.client.ext.ResponseExceptionMapper;

import javax.ws.rs.core.Response;
import javax.ws.rs.ext.Provider;
import java.util.logging.Logger;

@Provider
public class TempExceptionResponseMapper implements ResponseExceptionMapper<TempException> {

	private static final Logger log = Logger.getLogger("TempExceptionResponseMapper");

	@Override
	public TempException toThrowable(Response response) {
		int status = response.getStatus();
		String statusMsg = String.join("\n",
				"\n---------------------------\nClient call failed: \n---------------------------",
				String.format("Status: %s", status));

		TempException TempException;
		try {
			String message = response.readEntity(String.class);
			TempException = new TempException(status, message);
			statusMsg = String.join("\n", statusMsg,
					String.format("Message: %s",
							StringUtils.isNotBlank(message) ? message : "No message available"),
					"");
			log.finest(statusMsg);
		} catch (Exception e) {
			String message = e.getMessage();
			statusMsg = String.join("\n", statusMsg,
					String.format("Client call failed and response entity couldn't be read: %s",
							StringUtils.isNotBlank(message) ? message : "No message available"),
					"");
			TempException = new TempException(status, message);
			TempException.addSuppressed(e);
			log.finest(statusMsg);
		}

		return TempException;
	}
}

TempRepository.java

import java.util.List;

public interface TempRepository {

    List<Todo> getTodos() throws TempException;

}

TempRepositoryImpl.java

import org.eclipse.microprofile.rest.client.inject.RestClient;

import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import java.util.List;

@ApplicationScoped
public class TempRepositoryImpl implements TempRepository {

	@Inject
	@RestClient
	private TempClient tempClient;

	@Override
	public List<Todo> getTodos() throws TempException {
		List<Todo> join = tempClient.getTodos().exceptionally(throwable -> null).toCompletableFuture().join();
		System.out.println(join.get(0).getTitle());
		return join;
	}
}

TempResource.java

import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.logging.Logger;

@Produces(MediaType.APPLICATION_JSON)
@Path("/temp")
@ApplicationScoped
public class TempResource {

	@Inject
	TempRepository tempRepository;
	@Inject
	Logger log;

	@GET
	public Response getTodo() throws TempException {
		return Response.ok().entity(tempRepository.getTodos()).build();
	}

}

Todo.java

public class Todo {
	private int userId;
	private int id;
	private String title;
	private boolean completed;

	public int getUserId() {
		return userId;
	}

	public void setUserId(int userId) {
		this.userId = userId;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	public boolean isCompleted() {
		return completed;
	}

	public void setCompleted(boolean completed) {
		this.completed = completed;
	}
}