package org.apache.archiva.common.filelock;
   
   /*
    * 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.Closeable;
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.RandomAccessFile;
  import java.nio.channels.FileChannel;
  import java.nio.channels.FileLock;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicInteger;
  
  /**
   * @author Olivier Lamy
   * @since 2.0.0
   */
  public class Lock
  {
      private File file;
  
      private AtomicBoolean write;
  
      private final Map<Thread, AtomicInteger> fileClients = new HashMap<>();
  
      private FileLock fileLock;
  
      private RandomAccessFile randomAccessFile;
  
      private FileChannel fileChannel;
  
      public Lock( File file )
      {
          this.file = file;
      }
  
      public Lock( File file, boolean write )
          throws FileNotFoundException
      {
          this.file = file;
          this.write = new AtomicBoolean( write );
          randomAccessFile = new RandomAccessFile( file, write ? "rw" : "r" );
          fileChannel = randomAccessFile.getChannel();
      }
  
      public File getFile()
      {
          return file;
      }
  
      public AtomicBoolean isWrite()
      {
          return write;
      }
  
      public void setFile( File file )
      {
          this.file = file;
      }
  
      public void setWrite( boolean write )
      {
          this.write.set( write );
      }
  
      public boolean isShared()
      {
          return this.fileLock.isValid() && this.fileLock.isShared();
      }
  
      public boolean isValid()
      {
          return this.fileLock!=null && this.fileLock.isValid();
      }
  
      public Map<Thread, AtomicInteger> getFileClients()
      {
          return fileClients;
      }
 
     public void addFileClient( Thread thread )
     {
         this.fileClients.put( thread, new AtomicInteger( 1 ) );
     }
 
     public boolean removeFileClient( Thread thread )
     {
         return this.fileClients.remove( thread ) != null;
     }
 
     protected void close()
         throws IOException
     {
         IOException ioException = null;
         try
         {
             this.fileLock.release();
         }
         catch ( IOException e )
         {
             ioException = e;
         }
 
         closeQuietly( fileChannel );
         closeQuietly( randomAccessFile );
 
         fileClients.remove( Thread.currentThread() );
 
         if ( ioException != null )
         {
             throw ioException;
         }
 
     }
 
     protected void openLock( boolean write, boolean timeout )
         throws IOException
     {
         fileClients.put( Thread.currentThread(), new AtomicInteger( 1 ) );
 
         this.fileLock = timeout
             ? fileChannel.tryLock( 0L, Long.MAX_VALUE, write ? false : true )
             : fileChannel.lock( 0L, Long.MAX_VALUE, write ? false : true );
 
     }
 
     protected RandomAccessFile getRandomAccessFile()
     {
         return randomAccessFile;
     }
 
     private void closeQuietly( Closeable closeable )
     {
         try
         {
             closeable.close();
         }
         catch ( IOException e )
         {
             // ignore
         }
     }
 
 
     @Override
     public String toString()
     {
         final StringBuilder sb = new StringBuilder( "Lock{" );
         sb.append( "file=" ).append( file );
         sb.append( '}' );
         return sb.toString();
     }
 }