package com.simpligility.maven.plugins.androidndk.common;
   
   import org.apache.commons.io.IOUtils;
   import org.codehaus.plexus.util.IOUtil;
   
   import java.io.File;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Enumeration;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  /**
   * Helper class to deal with jar files.
   *
   * @author Johan Lindquist
   */
  public class JarHelper
  {
  
      /**
       * Listener for jar extraction.
       */
      public interface UnjarListener
      {
         boolean include( JarEntry jarEntry );
      }
  
      /**
       * Unjars the specified jar file into the the specified directory
       *
       * @param jarFile
       * @param outputDirectory
       * @param unjarListener
       * @throws IOException
       */
      public static void unjar( JarFile jarFile, File outputDirectory, UnjarListener unjarListener ) throws IOException
      {
          for ( Enumeration en = jarFile.entries(); en.hasMoreElements(); )
          {
              JarEntry entry = ( JarEntry ) en.nextElement();
              File entryFile = new File( outputDirectory, entry.getName() );
              if ( unjarListener.include( entry ) )
              {
                  // Create the output directory if need be
                  if ( ! entryFile.getParentFile().exists() )
                  {
                      if ( ! entryFile.getParentFile().mkdirs() )
                      {
                          throw new IOException( "Error creating output directory: " + entryFile.getParentFile() );
                      }
                  }
  
                  // If the entry is an actual file, unzip that too
                  if ( ! entry.isDirectory() )
                  {
                      final InputStream in = jarFile.getInputStream( entry );
                      try
                      {
                          final OutputStream out = new FileOutputStream( entryFile );
                          try
                          {
                              IOUtil.copy( in, out );
                          }
                          finally
                          {
                              IOUtils.closeQuietly( out );
                          }
                      }
                      finally
                      {
                          IOUtils.closeQuietly( in );
                      }
                  }
              }
          }
      }
  
  }