How to use

cascading.operation.expression.ScriptTupleFunction

constructor

private static Pipe addFunction( RelOptCluster cluster, RexProgram program, Pipe pipe )
 {
 final Fields incomingFields = createTypedFields( cluster, program.getInputRowType(), false );
 BlockBuilder statements = new BlockBuilder();
 List<Expression> expressionList = RexToLixTranslator.translateProjects(
  program,
  (JavaTypeFactory) cluster.getTypeFactory(),
  statements,
  new RexToLixTranslator.InputGetter()
  {
  public Expression field( BlockBuilder list, int index )
   {
   final Type type = incomingFields.getType( index );
   final String name = incomingFields.get( index ).toString();
   return Expressions.parameter( type, name );
   }
  } );
 Expression record = Expressions.newArrayInit( Object.class, expressionList );
 record = Expressions.new_( getConstructor(), record );
 statements.add( Expressions.return_( null, record ) );
 BlockStatement block = statements.toBlock();
 String expression = Expressions.toString( block );
 Fields outgoingFields = createTypedFields( cluster, program.getOutputRowType(), false );
 LOG.debug( "function parameters: {}", program.getInputRowType() );
 LOG.debug( "function results: {}", outgoingFields );
 LOG.debug( "function expression: {}", expression );
 Function scriptFunction = new ScriptTupleFunction( outgoingFields, expression, incomingFields.getTypesClasses() );
 return new Each( pipe, scriptFunction, Fields.RESULTS );
 }

private Object evaluate( String expression, Class returnType, TupleEntry tupleEntry )
 {
 ScriptTupleFunction function = new ScriptTupleFunction( new Fields( "result", returnType ), expression );
 ConcreteCall<ExpressionOperation.Context> call = new ConcreteCall<ExpressionOperation.Context>( tupleEntry.getFields(), function.getFieldDeclaration() );
 function.prepare( FlowProcess.NULL, call );
 return function.evaluate( call.getContext(), tupleEntry );
 }

private Object evaluate( String expression, String[] names, Class[] types, TupleEntry tupleEntry )
 {
 ScriptTupleFunction function = new ScriptTupleFunction( new Fields( "result" ), expression, names, types );
 ConcreteCall<ExpressionOperation.Context> call = new ConcreteCall<ExpressionOperation.Context>( tupleEntry.getFields(), function.getFieldDeclaration() );
 function.prepare( FlowProcess.NULL, call );
 return function.evaluate( call.getContext(), tupleEntry );
 }

private Object evaluate( String expression, Class returnType, TupleEntry tupleEntry )
 {
 ScriptTupleFunction function = new ScriptTupleFunction( new Fields( "result", returnType ), expression );
 ConcreteCall<ExpressionOperation.Context> call = new ConcreteCall<ExpressionOperation.Context>( tupleEntry.getFields(), function.getFieldDeclaration() );
 function.prepare( FlowProcess.NULL, call );
 return function.evaluate( call.getContext(), tupleEntry );
 }

private Object evaluate( String expression, String[] names, Class[] types, TupleEntry tupleEntry )
 {
 ScriptTupleFunction function = new ScriptTupleFunction( new Fields( "result" ), expression, names, types );
 ConcreteCall<ExpressionOperation.Context> call = new ConcreteCall<ExpressionOperation.Context>( tupleEntry.getFields(), function.getFieldDeclaration() );
 function.prepare( FlowProcess.NULL, call );
 return function.evaluate( call.getContext(), tupleEntry );
 }