/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you 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.
   */
  package org.jboss.netty.channel.socket.nio;
  
  import org.jboss.netty.util.ExternalResourceReleasable;
  import org.jboss.netty.util.internal.ExecutorUtil;
  
  import java.util.concurrent.Executor;
  import java.util.concurrent.atomic.AtomicInteger;
  
  public abstract class AbstractNioBossPool<E extends Boss>
          implements BossPool<E>, ExternalResourceReleasable {
  
      private final Boss[] bosses;
      private final AtomicInteger bossIndex = new AtomicInteger();
      private final Executor bossExecutor;
      private volatile boolean initDone;
  
      /**
       * Create a new instance
       *
       * @param bossExecutor the {@link Executor} to use for the {@link Boss}'s
       * @param bossCount the count of {@link Boss}'s to create
       */
      AbstractNioBossPool(Executor bossExecutor, int bossCount) {
          this(bossExecutor, bossCount, true);
      }
  
      AbstractNioBossPool(Executor bossExecutor, int bossCount, boolean autoInit) {
          if (bossExecutor == null) {
              throw new NullPointerException("bossExecutor");
          }
          if (bossCount <= 0) {
              throw new IllegalArgumentException(
                      "bossCount (" + bossCount + ") " +
                              "must be a positive integer.");
          }
          bosses = new Boss[bossCount];
          this.bossExecutor = bossExecutor;
          if (autoInit) {
              init();
          }
      }
  
      protected void init() {
          if (initDone) {
              throw new IllegalStateException("Init was done before");
          }
          initDone = true;
  
          for (int i = 0; i < bosses.length; i++) {
              bosses[i] = newBoss(bossExecutor);
          }
      }
  
      /**
       * Create a new {@link Boss} which uses the given {@link Executor} to service IO
       *
       *
       * @param executor the {@link Executor} to use
       * @return worker the new {@link Boss}
       */
      protected abstract E newBoss(Executor executor);
  
      @SuppressWarnings("unchecked")
      public E nextBoss() {
          return (E) bosses[Math.abs(bossIndex.getAndIncrement() % bosses.length)];
      }
  
      public void rebuildSelectors() {
          for (Boss boss: bosses) {
              boss.rebuildSelector();
          }
      }
  
      public void releaseExternalResources() {
          shutdown();
          ExecutorUtil.shutdownNow(bossExecutor);
      }
  
      public void shutdown() {
          for (Boss boss: bosses) {
              boss.shutdown();
          }
      }
  }