/*-
    * #%L
    * io.earcam.instrumental.lade.jpms
    * %%
    * Copyright (C) 2018 earcam
    * %%
    * SPDX-License-Identifier: (BSD-3-Clause OR EPL-1.0 OR Apache-2.0 OR MIT)
    * 
    * You <b>must</b> choose to accept, in full - any individual or combination of 
   * the following licenses:
   * <ul>
   * 	<li><a href="https://opensource.org/licenses/BSD-3-Clause">BSD-3-Clause</a></li>
   * 	<li><a href="https://www.eclipse.org/legal/epl-v10.html">EPL-1.0</a></li>
   * 	<li><a href="https://www.apache.org/licenses/LICENSE-2.0">Apache-2.0</a></li>
   * 	<li><a href="https://opensource.org/licenses/MIT">MIT</a></li>
   * </ul>
   * #L%
   */
  package io.earcam.acme.app;
  
  import java.util.ServiceLoader;
  import java.util.stream.StreamSupport;
  
  import io.earcam.acme.api.AcmeApi;
  
  public class AcmeApp {
  
  	public static void main(String[] args)
  	{
  		Module module = AcmeApp.class.getModule();
  		AcmeApi implementation = loadService(module);
  
  		String msg = implementation.greet(args[0]);
  
  		System.out.println(module + ": " + msg);
  	}
  
  
  	private static AcmeApi loadService(Module module)
  	{
  		ServiceLoader<AcmeApi> services = loadServiceLoader(module);
  
  		return StreamSupport
  				.stream(services.spliterator(), false)
  				.findFirst()
  				.orElseThrow(NullPointerException::new);
  	}
  
  
  	private static ServiceLoader<AcmeApi> loadServiceLoader(Module module)
  	{
  		ModuleLayer layer = module.getLayer();
  
  		ServiceLoader<AcmeApi> services = (layer == null) ? ServiceLoader.load(AcmeApi.class) : ServiceLoader.load(layer, AcmeApi.class);
  		return services;
  	}
  }