How to use

NullScheme

in

cascading.scheme

public NullTap() {
 super(new NullScheme<JobConf, RecordReader, OutputCollector, Object, Object>());
 id = UUID.randomUUID();
}

protected Tap createTap( JobConf jobConf, Path path, SinkMode sinkMode )
 {
 return new Hfs( new NullScheme(), path.toString(), sinkMode );
 }

protected Tap createTap( JobConf jobConf, Path path, SinkMode sinkMode )
 {
 return new Hfs( new NullScheme(), path.toString(), sinkMode );
 }

public NonTap( Fields fields )
 {
 super( new NullScheme( fields, fields ) );
 }

public NonTap()
 {
 super( new NullScheme( Fields.UNKNOWN, Fields.ALL ) );
 }

@Override
public Scheme getScheme()
 {
 if( super.getScheme() != null )
  return super.getScheme();
 Set<Fields> fields = new HashSet<Fields>();
 for( Tap child : getTaps() )
  fields.add( child.getSinkFields() );
 // if all schemes have the same sink fields, the just use the scheme
 if( fields.size() == 1 )
  {
  setScheme( getTaps()[ 0 ].getScheme() );
  return super.getScheme();
  }
 Fields allFields = Fields.merge( fields.toArray( new Fields[ fields.size() ] ) );
 setScheme( new NullScheme( allFields, allFields ) );
 return super.getScheme();
 }