content: /*
   * Copyright 2014-2025 Real Logic Limited.
   *
   * 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
   *
   * https://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.
   */
  package io.aeron.samples;
  
  import io.aeron.Aeron;
  import io.aeron.Subscription;
  import io.aeron.driver.MediaDriver;
  import io.aeron.logbuffer.FragmentHandler;
  import org.agrona.concurrent.ShutdownSignalBarrier;
  
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * This is a Basic Aeron subscriber application.
   * <p>
   * The application subscribes to a default channel and stream ID. These defaults can
   * be overwritten by changing their value in {@link SampleConfiguration} or by
   * setting their corresponding Java system properties at the command line, e.g.:
   * -Daeron.sample.channel=aeron:udp?endpoint=localhost:5555 -Daeron.sample.streamId=20
   * This application only handles non-fragmented data. A DataHandler method is called
   * for every received message or message fragment.
   * For an example that implements reassembly of large, fragmented messages, see
   * {@link MultipleSubscribersWithFragmentAssembly}.
   */
  public class BasicSubscriber
  {
      private static final int STREAM_ID = SampleConfiguration.STREAM_ID;
      private static final String CHANNEL = SampleConfiguration.CHANNEL;
      private static final int FRAGMENT_COUNT_LIMIT = SampleConfiguration.FRAGMENT_COUNT_LIMIT;
      private static final boolean EMBEDDED_MEDIA_DRIVER = SampleConfiguration.EMBEDDED_MEDIA_DRIVER;
  
      /**
       * Main method for launching the process.
       *
       * @param args passed to the process.
       */
      @SuppressWarnings("try")
      public static void main(final String[] args)
      {
          System.out.println("Subscribing to " + CHANNEL + " on stream id " + STREAM_ID);
          final AtomicBoolean running = new AtomicBoolean(true);
          try (ShutdownSignalBarrier barrier = new ShutdownSignalBarrier(() -> running.set(false));
              MediaDriver driver = EMBEDDED_MEDIA_DRIVER ?
                  MediaDriver.launchEmbedded(new MediaDriver.Context().terminationHook(barrier::signalAll)) : null)
          {
              final Aeron.Context ctx = new Aeron.Context()
                  .availableImageHandler(SamplesUtil::printAvailableImage)
                  .unavailableImageHandler(SamplesUtil::printUnavailableImage);
  
              if (EMBEDDED_MEDIA_DRIVER)
              {
                  ctx.aeronDirectoryName(driver.aeronDirectoryName());
              }
  
              final FragmentHandler fragmentHandler = SamplesUtil.printAsciiMessage(STREAM_ID);
  
              // Create an Aeron instance using the configured Context and create a
              // Subscription on that instance that subscribes to the configured
              // channel and stream ID.
              // The Aeron and Subscription classes implement "AutoCloseable" and will automatically
              // clean up resources when this try block is finished
              try (Aeron aeron = Aeron.connect(ctx);
                  Subscription subscription = aeron.addSubscription(CHANNEL, STREAM_ID))
              {
                  SamplesUtil.subscriberLoop(fragmentHandler, FRAGMENT_COUNT_LIMIT, running).accept(subscription);
  
                  System.out.println("Shutting down...");
              }
          }
      }
  }
  