oracle.ifs.utils.common

Class Deque

java.lang.Object

oracle.ifs.utils.common.Deque

public class Deque
extends Object

This is a utility class implementing a deque. A deque is basically a double ended queue. With a queue, you put elements in the back and take them out from the front. With a stack, you put elements in the front, and take them out from the front as well. A deque allows you to put elements in either the back or front, and take them out from the back or front. This particular implementation of a deque uses a circular buffer that grows when more space is needed. The push and pop operations all execute in constant amortized time. Note that this class is unsynchronized, and therefore not threadsafe. This is done to give a performance benefit for single threaded usage. If you need a threadsafe deque, just synchronize on every method call. Or, subclass Deque and make all of the methods synchronized.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	m_Back the index into m_Objs that indicates the back of the queue
protected int	m_Len the number of elements in the Deque
protected Object[]	m_Objs

Constructor Summary

Constructors

Constructor and Description
Deque() Construct an empty Deque.
Deque(int size) Construct an empty Deque with the provided initial buffer size.

Method Summary

Modifier and Type	Method and Description
void	copyInto(Object[] dest) Copy every element in this Deque into the given array.
void	copyInto(Object[] dest, int offset) Copy every element in this Deque into the given array, starting at the given offset into the array.
Object	popBack() Remove an object from the back of this Deque
Object	popFront() Remove an object from the front of this Deque
void	pushBack(Object o) Insert an object on the back of this Deque
void	pushFront(Object o) Insert an object on the front of this Deque
int	size() Return the number of elements currently in this Deque.

Methods inherited from class java.lang.Object

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

Field Detail

m_Objs

protected Object[] m_Objs

m_Back

protected int m_Back

the index into m_Objs that indicates the back of the queue

m_Len

protected int m_Len

the number of elements in the Deque

Constructor Detail

Deque

public Deque()

Construct an empty Deque.

Deque

public Deque(int size)

Construct an empty Deque with the provided initial buffer size.

Parameters:

size - - the initial capacity of this Deque

Method Detail

pushFront

public void pushFront(Object o)

Insert an object on the front of this Deque

Parameters:

o - - the object to insert

pushBack

public void pushBack(Object o)

Insert an object on the back of this Deque

Parameters:

o - - the object to insert

popFront

public Object popFront()

Remove an object from the front of this Deque

Returns:

the object removed

popBack

public Object popBack()

Remove an object from the back of this Deque

Returns:

the object removed

size

public int size()

Return the number of elements currently in this Deque.

copyInto

public void copyInto(Object[] dest)

Copy every element in this Deque into the given array.

Parameters:

dest - - the destination array

copyInto

public void copyInto(Object[] dest,
                     int offset)

Copy every element in this Deque into the given array, starting at the given offset into the array.

Parameters:

dest - - the destination array

offset - - the index into dest at which the copying begins.