package org.apache.maven.plugin.surefire.booterclient.lazytestprovider;
   
   /*
    * 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 java.util.Collection;
  import java.util.Collections;
  import java.util.Properties;
  import java.util.concurrent.ConcurrentLinkedDeque;
  
  import org.apache.maven.shared.utils.cli.CommandLineException;
  import org.apache.maven.shared.utils.cli.CommandLineUtils;
  import org.apache.maven.shared.utils.cli.Commandline;
  
  /**
   * A {@link Commandline} implementation that provides the output stream of
   * the executed process in form of a {@link FlushReceiver}, for it to be
   * flushed on demand.
   *
   * @author Andreas Gudian
   */
  public class OutputStreamFlushableCommandline
      extends Commandline
      implements FlushReceiverProvider
  {
      private final Collection<String> excludedEnvironmentVariables;
      private volatile FlushReceiver flushReceiver;
  
      /**
       * for testing purposes only
       */
      public OutputStreamFlushableCommandline()
      {
          this( new String[0] );
      }
  
      public OutputStreamFlushableCommandline( String[] excludedEnvironmentVariables )
      {
          this.excludedEnvironmentVariables = new ConcurrentLinkedDeque<>();
          Collections.addAll( this.excludedEnvironmentVariables, excludedEnvironmentVariables );
      }
  
      @Override
      public final void addSystemEnvironment()
      {
          Properties systemEnvVars = CommandLineUtils.getSystemEnvVars();
  
          for ( String key : systemEnvVars.stringPropertyNames() )
          {
              if ( !excludedEnvironmentVariables.contains( key ) )
              {
                  addEnvironment( key, systemEnvVars.getProperty( key ) );
              }
          }
      }
  
      @Override
      public Process execute()
          throws CommandLineException
      {
          Process process = super.execute();
  
          if ( process.getOutputStream() != null )
          {
              flushReceiver = new OutputStreamFlushReceiver( process.getOutputStream() );
          }
  
          return process;
      }
  
      @Override
      public FlushReceiver getFlushReceiver()
      {
          return flushReceiver;
      }
  }