Class QueryStream

java.lang.Object
com.sparsity.sparksee.gdb.QueryStream
public class QueryStream extends Object
Query stream interface.

A QueryStream is the interface between the application and the STREAM operator. When the operator starts inside a Query, the method is prepared with query-defined arguments. Then, if there are input operations, the STREAM operator builds the ResultSets and starts the iteration. Finally, the operator fetches rows until no more are available.

Application exceptions must be cached by the subclass that implements the interface.

Author:
Sparsity Technologies http://www.sparsity-technologies.com

  • Method Details

    • fetch

      public boolean fetch(ValueList list)
      Gets the next row and moves the iterator forward.

      The end of sequence is denoted by returning TRUE with an empty row. A valid row must contain as many values (even NULL) as expected by the query.

      Parameters:
      list - [out] Storage for the new rows
      Returns:
      TRUE if there is a row or end of sequence, FALSE on error

    • prepare

      public boolean prepare(ValueList list)
      Prepares the stream before it is started.

      Parameters:
      list - [in] Optional list of arguments
      Returns:
      FALSE on error

    • start

      public boolean start(ResultSetList list)
      Starts the stream.

      Parameters:
      list - [in] Optional list of input ResultSets
      Returns:
      FALSE on error