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 org.agrona.nio;
  
  import org.agrona.LangUtil;
  
  import java.io.IOException;
  import java.io.UncheckedIOException;
  import java.nio.channels.Selector;
  
  /**
   * Implements the common functionality for a transport poller.
   */
  public class TransportPoller implements AutoCloseable
  {
      /**
       * System property name for the threshold beyond which individual channel/socket polling will swap to using
       * a {@link Selector}.
       */
      public static final String ITERATION_THRESHOLD_PROP_NAME = "org.agrona.transport.iteration.threshold";
  
      /**
       * Default threshold beyond which individual channel/socket polling will swap to using a {@link Selector}.
       */
      public static final int ITERATION_THRESHOLD_DEFAULT = 5;
  
      /**
       * Threshold beyond which individual channel/socket polling will swap to using a {@link Selector}.
       *
       * @see #ITERATION_THRESHOLD_PROP_NAME
       * @see #ITERATION_THRESHOLD_DEFAULT
       */
      public static final int ITERATION_THRESHOLD = Integer.getInteger(
          ITERATION_THRESHOLD_PROP_NAME, ITERATION_THRESHOLD_DEFAULT);
  
      /**
       * Reference to the {@link Selector} for the transport.
       */
      protected final Selector selector;
  
      /**
       * Default constructor.
       */
      public TransportPoller()
      {
          try
          {
              selector = Selector.open(); // yes, SelectorProvider, blah, blah
          }
          catch (final IOException ex)
          {
              throw new UncheckedIOException(ex);
          }
      }
  
      /**
       * Close NioSelector down. Returns immediately.
       */
      public void close()
      {
          selector.wakeup();
          try
          {
              selector.close();
          }
          catch (final IOException ex)
          {
              LangUtil.rethrowUnchecked(ex);
          }
      }
  
      /**
       * Explicit call to {@link Selector#selectNow()} followed by clearing out the set without processing.
       */
      public void selectNowWithoutProcessing()
      {
          try
          {
              selector.selectNow();
          }
          catch (final IOException ex)
          {
              LangUtil.rethrowUnchecked(ex);
          }
      }
  }
  