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 Summary

Fields

Modifier and Type	Field	Description
protected LongBigArray	array	The backing array.
protected long	end	The end position in array.
static final long	INITIAL_CAPACITY	The standard initial capacity of a queue.
protected long	length	The current (cached) length of array.
protected long	start	The start position in array.

Constructor Summary

Constructors

Constructor	Description
LongBigArrayFIFOQueue()	Creates a new empty queue with standard initial capacity.
LongBigArrayFIFOQueue(long capacity)	Creates a new empty queue with given capacity.

Method Summary

Modifier and Type	Method	Description
void	clear()
it.unimi.dsi.fastutil.longs.LongComparator	comparator()
long	dequeueLastLong()	Dequeues the last element from the queue.
long	dequeueLong()
void	enqueue(long x)
void	enqueueFirst(long x)	Enqueues a new element as the first element (in dequeuing order) of the queue.
long	firstLong()
boolean	isEmpty()
long	lastLong()
long	longSize()
int	size()
long	sizeOf()
void	trim()	Trims the queue to the smallest possible size.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.longs.LongPriorityQueue

dequeue, enqueue, first, last

Methods inherited from interface it.unimi.dsi.fastutil.PriorityQueue

changed

Field Details

INITIAL_CAPACITY

public static final long INITIAL_CAPACITY

The standard initial capacity of a queue.

See Also:

• Constant Field Values

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>