Package org.rumbledb.runtime.cursor

Interface Cursor<T>

Type Parameters:
T - the value type returned by this cursor
All Superinterfaces:
AutoCloseable
All Known Implementing Classes:
AbstractLocalCursor, AtMostOneLocalCursor, ConcatLocalCursor, ContextOrArgumentLocalCursor, FlatMappingLocalCursor, IteratorLocalCursor, MappingLocalCursor
public interface Cursor<T> extends AutoCloseable
Mutable state for one local evaluation of a RuntimePlan.

A cursor has a single owner, is single-use, and must not be shared between evaluations. Its lifecycle is created -> open -> closed; closing an already closed cursor should be harmless. A fresh cursor replaces the reset and cloning operations used by the legacy iterator architecture. Implementations should normally extend AbstractLocalCursor instead of implementing lifecycle handling themselves.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Releases resources owned by this evaluation.
    boolean
    hasNext()
     
    T
    next()
     

  • Method Details

    • hasNext

      boolean hasNext()
      Returns:
      whether another value is available Opens the cursor if needed, then returns whether another value is available.

    • next

      T next()
      Returns:
      the next value Opens the cursor if needed, then returns the next value.

    • close

      void close()
      Releases resources owned by this evaluation. This method is idempotent.
      Specified by:
      close in interface AutoCloseable