org.antlr.runtime.misc

Class FastQueue<T>

java.lang.Object

org.antlr.runtime.misc.FastQueue<T>

Direct Known Subclasses:

LookaheadStream

public class FastQueue<T>
extends Object

A queue that can dequeue and get(i) in O(1) and grow arbitrarily large. A linked list is fast at dequeue but slow at get(i). An array is the reverse. This is O(1) for both operations. List grows until you dequeue last element at end of buffer. Then it resets to start filling at 0 again. If adds/removes are balanced, the buffer will not grow too large. No iterator stuff as that's not how we'll use it.

Field Summary

Fields

Modifier and Type	Field and Description
protected List<T>	data dynamically-sized buffer of elements
protected int	p index of next element to fill
protected int	range

Constructor Summary

Constructors

Constructor and Description
FastQueue()

Method Summary

Methods

Modifier and Type	Method and Description
void	add(T o)
void	clear()
T	elementAt(int i) Return element i elements ahead of current element.
T	head()
int	range()
T	remove() Get and remove first element in queue
void	reset()
int	size()
String	toString() Return string of current buffer contents; non-destructive

Methods inherited from class java.lang.Object

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

Field Detail

data

protected List<T> data

dynamically-sized buffer of elements

p

protected int p

index of next element to fill

range

protected int range

Constructor Detail

FastQueue

public FastQueue()

Method Detail

reset

public void reset()

clear

public void clear()

remove

public T remove()

Get and remove first element in queue

add

public void add(T o)

size

public int size()

range

public int range()

head

public T head()

elementAt

public T elementAt(int i)

Return element i elements ahead of current element. i==0 gets current element. This is not an absolute index into data since p defines the start of the real list.

toString

public String toString()

Return string of current buffer contents; non-destructive

Overrides:

toString in class Object