package org.apache.maven.surefire.util;

 /*

  * 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.BufferedReader;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.PrintStream;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Iterator;

 import java.util.List;

 import org.apache.maven.surefire.booter.ForkingRunListener;

 /**

  * A variant of TestsToRun that is provided with test class names

  * from an {@link InputStream} (e.g. {@code System.in}). The method

  * {@link #iterator()} returns an Iterator that blocks on calls to

  * {@link Iterator#hasNext()} until new classes are available, or no more

  * classes will be available.

  *

  * @author Andreas Gudian

  */

 public class LazyTestsToRun

     extends TestsToRun

 {

     private List workQueue = new ArrayList();

     private BufferedReader inputReader;

     private boolean streamClosed = false;

     private ClassLoader testClassLoader;

     private PrintStream originalOutStream;

     /**

      * C'tor

      *

      * @param testSource        source to read the tests from

      * @param testClassLoader   class loader to load the test classes

      * @param originalOutStream the output stream to use when requesting new new tests

      */

     public LazyTestsToRun( InputStream testSource, ClassLoader testClassLoader, PrintStream originalOutStream )

     {

         super( Collections.emptyList() );

         this.testClassLoader = testClassLoader;

         this.originalOutStream = originalOutStream;

         inputReader = new BufferedReader( new InputStreamReader( testSource ) );

     }

     protected void addWorkItem( String className )

     {

         synchronized ( workQueue )

         {

             workQueue.add( ReflectionUtils.loadClass( testClassLoader, className ) );

         }

     }

     protected void requestNextTest()

     {

         StringBuffer sb = new StringBuffer();

         sb.append( (char) ForkingRunListener.BOOTERCODE_NEXT_TEST ).append( ",0,want more!\n" );

         originalOutStream.print( sb.toString() );

     }

     private class BlockingIterator

         implements Iterator

     {

         private int lastPos = -1;

         public boolean hasNext()

         {

             int nextPos = lastPos + 1;

             synchronized ( workQueue )

             {

                 if ( workQueue.size() > nextPos )

                 {

                     return true;

                 }

                 else

                 {

                     if ( needsToWaitForInput( nextPos ) )

                     {

                         requestNextTest();

                         String nextClassName;

                         try

                         {

                             nextClassName = inputReader.readLine();

                         }

                         catch ( IOException e )

                         {

                             streamClosed = true;

                             return false;

                         }

                         if ( null == nextClassName )

                         {

                             streamClosed = true;

                         }

                         else

                         {

                             addWorkItem( nextClassName );

                         }

                     }

                     return ( workQueue.size() > nextPos );

                 }

             }

         }

         private boolean needsToWaitForInput( int nextPos )

         {

             return workQueue.size() == nextPos && !streamClosed;

         }

         public Object next()

         {

             synchronized ( workQueue )

             {

                 return workQueue.get( ++lastPos );

             }

         }

         public void remove()

         {

             throw new UnsupportedOperationException();

         }

     }

     /* (non-Javadoc)

       * @see org.apache.maven.surefire.util.TestsToRun#iterator()

       */

     public Iterator iterator()

     {

         return new BlockingIterator();

     }

     /* (non-Javadoc)

       * @see org.apache.maven.surefire.util.TestsToRun#toString()

       */

     public String toString()

     {

         StringBuffer sb = new StringBuffer( "LazyTestsToRun " );

         synchronized ( workQueue )

         {

             sb.append( "(more items expected: " ).append( !streamClosed ).append( "): " );

             sb.append( workQueue );

         }

         return sb.toString();

     }

     /* (non-Javadoc)

      * @see org.apache.maven.surefire.util.TestsToRun#allowEagerReading()

      */

     public boolean allowEagerReading() {

         return false;

     }

 }