Package mondrian.calc

Class TupleCollections

java.lang.Object
mondrian.calc.TupleCollections
public final class TupleCollections extends Object
Utility methods for tuple collections and iterators.
Author:
jhyde
See Also:

  • Method Details

    • createList

      public static TupleList createList(int arity)
      Creates a list of given arity.

      If arity == 1, creates a UnaryTupleList; if arity == 0, creates a DelegatingTupleList; otherwise creates a ArrayTupleList.

      Parameters:
      arity - Arity
      Returns:
      Tuple list
      See Also:

    • createList

      public static TupleList createList(int arity, int initialCapacity)
      Creates a list of given arity and initial capacity.

      If arity == 1, creates a UnaryTupleList; if arity == 0, creates a DelegatingTupleList; otherwise creates a ArrayTupleList.

      Parameters:
      arity - Arity
      initialCapacity - Initial capacity
      Returns:
      Tuple list
      See Also:

    • emptyList

      public static TupleList emptyList(int arity)
      Returns an empty TupleList of given arity.
      Parameters:
      arity - Number of members per tuple
      Returns:
      Empty tuple list

    • unmodifiableList

      public static TupleList unmodifiableList(TupleList list)
      Creates an unmodifiable TupleList backed by a given list.
      Parameters:
      list - the list for which an unmodifiable view is to be returned.
      Returns:
      an unmodifiable view of the specified list.
      See Also:

    • iterator

      public static TupleIterator iterator(TupleCursor cursor)
      Adapts a TupleCursor into a TupleIterator.

      Since the latter is a more difficult API to implement, the wrapper has some extra state.

      This method may be used to implement TupleIterable.tupleIterator() for a TupleIterable or TupleList that only has a TupleCursor implementation.

      Parameters:
      cursor - Cursor
      Returns:
      Tuple iterator view onto the cursor

    • slice

      public static Iterable<Member> slice(TupleIterable tupleIterable, int column)
      Creates a slice of a TupleIterable.

      Can be used as an implementation for TupleList.slice(int).

      Parameters:
      tupleIterable - Iterable
      column - Which member of each tuple of project.
      Returns:
      Iterable that returns a given member of each tuple

    • asMemberArrayIterable

      public static Iterable<Member[]> asMemberArrayIterable(TupleIterable tupleIterable)
      Converts a TupleIterable to an old-style iterable that creates an iterator over member arrays.
      Parameters:
      tupleIterable - Tuple iterable
      Returns:
      Iterable that creates an iterator over tuples represented as member arrays

    • asMemberArrayList

      public static List<Member[]> asMemberArrayList(TupleList tupleList)
      Converts a TupleList to an old-style list of member arrays.
      Parameters:
      tupleList - Tuple list
      Returns:
      List of member arrays

    • asTupleList

      public static TupleList asTupleList(List list)
      Converts an old-style list (members or member arrays) to a TupleList.

      Deduces the arity of the list from the first element, if the list is not empty. Otherwise assumes arity 1.

      If the list happens to be a tuple list, returns unchanged.

      Parameters:
      list - Old-style list
      Returns:
      Tuple list

    • materialize

      public static TupleList materialize(TupleIterable tupleIterable, boolean eager)
      Converts a TupleIterable into a TupleList.

      If the iterable is already a list, returns the iterable. If it is not a list, the behavior depends on the eager parameter. With eager = true, creates a list and populates it with the contents of the iterable. With eager = false, wraps in an adapter that implements the list interface and materializes to a list the first time that an operation that is in TupleList but not TupleIterable -- for example, TupleList.get(int, int) or List.size() -- is called.

      Parameters:
      tupleIterable - Iterable
      eager - Whether to convert into a list now, as opposed to on first use of a random-access method such as size or get.
      Returns:
      List