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.io.IOException;

 import java.io.InputStream;

 import java.util.Queue;

 import java.util.concurrent.Semaphore;

 /**

  * An {@link InputStream} that, when read, provides test class names out of a queue.

  * <p/>

  * The Stream provides only one test at a time, but only after {@link #provideNewTest()} has been invoked.

  * <p/>

  * After providing each test class name, followed by a newline character, a flush is performed on the

  * {@link FlushReceiver} provided by the {@link FlushReceiverProvider} that can be set using

  * {@link #setFlushReceiverProvider(FlushReceiverProvider)}.

  * 

  * @author Andreas Gudian

  */

 public class TestProvidingInputStream

     extends InputStream

 {

     private final Queue<String> testItemQueue;

     private byte[] currentBuffer;

     private int currentPos;

     private Semaphore semaphore = new Semaphore( 0 );

     private FlushReceiverProvider flushReceiverProvider;

     private boolean closed = false;

     /**

      * C'tor

      * 

      * @param testItemQueue source of the tests to be read from this stream

      */

     public TestProvidingInputStream( Queue<String> testItemQueue )

     {

         this.testItemQueue = testItemQueue;

     }

     /**

      * @param flushReceiverProvider the provider for a flush receiver.

      */

     public void setFlushReceiverProvider( FlushReceiverProvider flushReceiverProvider )

     {

         this.flushReceiverProvider = flushReceiverProvider;

     }

     @Override

     public synchronized int read()

         throws IOException

     {

         if ( null == currentBuffer )

         {

             if ( null != flushReceiverProvider && null != flushReceiverProvider.getFlushReceiver() )

             {

                 flushReceiverProvider.getFlushReceiver().flush();

             }

             semaphore.acquireUninterruptibly();

             if ( closed )

             {

                 return -1;

             }

             String currentElement = testItemQueue.poll();

             if ( null != currentElement )

             {

                 currentBuffer = currentElement.getBytes();

                 currentPos = 0;

             }

             else

             {

                 return -1;

             }

         }

         if ( currentPos < currentBuffer.length )

         {

             return ( currentBuffer[currentPos++] & 0xff );

         }

         else

         {

             currentBuffer = null;

             return ( '\n' & 0xff );

         }

     }

     /**

      * Signal that a new test is to be provided.

      */

     public void provideNewTest()

     {

         semaphore.release();

     }

     public void close()

     {

         closed = true;

         semaphore.release();

     }

 }