Package io.trino.util

Class LongBigArrayFIFOQueue

java.lang.Object
io.trino.util.LongBigArrayFIFOQueue
All Implemented Interfaces:
it.unimi.dsi.fastutil.longs.LongPriorityQueue, it.unimi.dsi.fastutil.PriorityQueue<Long>
public class LongBigArrayFIFOQueue extends Object implements it.unimi.dsi.fastutil.longs.LongPriorityQueue
A type-specific array-based FIFO queue, supporting also deque operations.

Instances of this class represent a FIFO queue using a backing array in a circular way. The array is enlarged and shrunk as needed. You can use the trim() method to reduce its memory usage, if necessary.

This class provides additional methods that implement a deque (double-ended queue).

  • Field Details

    • INITIAL_CAPACITY

      public static final long INITIAL_CAPACITY
      The standard initial capacity of a queue.
      See Also:

    • array

      protected LongBigArray array
      The backing array.

    • length

      protected long length
      The current (cached) length of array.

    • start

      protected long start
      The start position in array. It is always strictly smaller than length.

    • end

      protected long end
      The end position in array. It is always strictly smaller than length. Might be actually smaller than start because array is used cyclically.

  • Constructor Details

    • LongBigArrayFIFOQueue

      public LongBigArrayFIFOQueue(long capacity)
      Creates a new empty queue with given capacity.
      Parameters:
      capacity - the initial capacity of this queue.

    • LongBigArrayFIFOQueue

      public LongBigArrayFIFOQueue()
      Creates a new empty queue with standard initial capacity.

  • Method Details

    • sizeOf

      public long sizeOf()

    • comparator

      public it.unimi.dsi.fastutil.longs.LongComparator comparator()

      This implementation returns null (FIFO queues have no comparator).

      Specified by:
      comparator in interface it.unimi.dsi.fastutil.longs.LongPriorityQueue
      Specified by:
      comparator in interface it.unimi.dsi.fastutil.PriorityQueue<Long>

    • dequeueLong

      public long dequeueLong()
      Specified by:
      dequeueLong in interface it.unimi.dsi.fastutil.longs.LongPriorityQueue

    • dequeueLastLong

      public long dequeueLastLong()
      Dequeues the last element from the queue.
      Returns:
      the dequeued element.
      Throws:
      NoSuchElementException - if the queue is empty.

    • enqueue

      public void enqueue(long x)
      Specified by:
      enqueue in interface it.unimi.dsi.fastutil.longs.LongPriorityQueue

    • enqueueFirst

      public void enqueueFirst(long x)
      Enqueues a new element as the first element (in dequeuing order) of the queue.
      Parameters:
      x - the element to enqueue.

    • firstLong

      public long firstLong()
      Specified by:
      firstLong in interface it.unimi.dsi.fastutil.longs.LongPriorityQueue

    • lastLong

      public long lastLong()
      Specified by:
      lastLong in interface it.unimi.dsi.fastutil.longs.LongPriorityQueue

    • clear

      public void clear()
      Specified by:
      clear in interface it.unimi.dsi.fastutil.PriorityQueue<Long>

    • trim

      public void trim()
      Trims the queue to the smallest possible size.

    • size

      public int size()
      Specified by:
      size in interface it.unimi.dsi.fastutil.PriorityQueue<Long>

    • longSize

      public long longSize()

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface it.unimi.dsi.fastutil.PriorityQueue<Long>