package org.apache.maven.plugin.surefire.booterclient.output;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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.
   */
  
  import org.apache.maven.shared.utils.cli.StreamConsumer;
  import org.apache.maven.surefire.util.internal.DaemonThreadFactory;
  
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.LinkedBlockingQueue;
  
  /**
   * Knows how to reconstruct *all* the state transmitted over stdout by the forked process.
   *
   * @author Kristian Rosenvold
   */
  public final class ThreadedStreamConsumer
      implements StreamConsumer
  {
      private static final String POISON = "Pioson";
  
      private static final int ITEM_LIMIT_BEFORE_SLEEP = 10000;
  
      private final BlockingQueue<String> items = new LinkedBlockingQueue<String>();
  
      private final Thread thread;
  
      private final Pumper pumper;
  
      static class Pumper
          implements Runnable
      {
          private final BlockingQueue<String> queue;
  
          private final StreamConsumer target;
  
          private volatile Throwable throwable;
  
  
          Pumper( BlockingQueue<String> queue, StreamConsumer target )
          {
              this.queue = queue;
              this.target = target;
          }
  
          public void run()
          {
              try
              {
                  String item = queue.take();
                  //noinspection StringEquality
                  while ( item != POISON )
                  {
                      target.consumeLine( item );
                      item = queue.take();
                  }
              }
              catch ( Throwable t )
              {
                  // Think about what happens if the producer overruns us and creates an OOME. Not nice.
                  // Maybe limit length of blocking queue
                  this.throwable = t;
              }
          }
  
          public Throwable getThrowable()
          {
              return throwable;
          }
      }
  
      public ThreadedStreamConsumer( StreamConsumer target )
      {
          pumper = new Pumper( items, target );
          thread = DaemonThreadFactory.newDaemonThread( pumper, "ThreadedStreamConsumer" );
          thread.start();
      }
  
      @SuppressWarnings( "checkstyle:emptyblock" )
      public void consumeLine( String s )
      {
          items.add( s );
          if ( items.size() > ITEM_LIMIT_BEFORE_SLEEP )
         {
             try
             {
                 Thread.sleep( 100 );
             }
             catch ( InterruptedException ignore )
             {
             }
         }
     }
 
 
     public void close()
     {
         try
         {
             items.add( POISON );
             thread.join();
         }
         catch ( InterruptedException e )
         {
             throw new RuntimeException( e );
         }
 
         //noinspection ThrowableResultOfMethodCallIgnored
         if ( pumper.getThrowable() != null )
         {
             throw new RuntimeException( pumper.getThrowable() );
         }
     }
 }