craterdog.collections

Class Queue<E>

java.lang.Object

craterdog.smart.SmartObject<Sequence<E>>

craterdog.collections.abstractions.Sequence<E>

craterdog.collections.abstractions.Collection<E>

craterdog.collections.abstractions.ClosedCollection<E>

craterdog.collections.Queue<E>

Type Parameters:

E - The type of element managed by this collection.

All Implemented Interfaces:

craterdog.core.Composite, craterdog.core.Sequential<E>, java.lang.Comparable<Sequence<E>>, java.lang.Iterable<E>

public class Queue<E>
extends ClosedCollection<E>

This collection class implements a queue (FIFO) data structure. Normally, multiple threads will be accessing a queue at the same time. This class enforces synchronized access to all methods of this class. The implementation dynamically scales up and down the size of the underlying data structures as the number elements changes over time.

Author:

Derk Norton

Field Summary

Fields inherited from class craterdog.collections.abstractions.ClosedCollection

list

Constructor Summary

Constructors

Constructor and Description
Queue() This constructor creates a new queue of unlimited capacity.
Queue(int capacity) This constructor creates a new queue with the specified capacity.

Method Summary

Modifier and Type	Method and Description
void	addElement(E element) This method adds a new element to the tail of the queue.
Queue<E>	copy()
E	getHead() This method returns a reference to the element at the head of the queue without removing the element from the queue.
E	removeElement() This method removes the next element from the head of the queue.
E[]	toArray()

Methods inherited from class craterdog.collections.abstractions.ClosedCollection

createIterator, getElement, getElements, getIndex, getSize, removeAll

Methods inherited from class craterdog.collections.abstractions.Collection

containsAll, containsAny, containsElement, normalizedIndex

Methods inherited from class craterdog.collections.abstractions.Sequence

compareTo, equals, hashCode

Methods inherited from class craterdog.smart.SmartObject

addSerializableClass, addSerializableClass, addSerializableClass, createMapper, fromString, fromString, toExposedString, toString, toString, toString, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface craterdog.core.Sequential

isEmpty, iterator

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

Queue

public Queue()

This constructor creates a new queue of unlimited capacity.

Queue

public Queue(int capacity)

This constructor creates a new queue with the specified capacity.

Parameters:

capacity - The maximum number of elements that can be in the queue at one time.

Method Detail

toArray

public E[] toArray()

Specified by:

toArray in interface craterdog.core.Sequential<E>

Overrides:

toArray in class Sequence<E>

copy

public Queue<E> copy()

Overrides:

copy in class craterdog.smart.SmartObject<Sequence<E>>

addElement

public final void addElement(E element)
                      throws java.lang.InterruptedException

This method adds a new element to the tail of the queue. If the queue is currently at capacity this method will block until the capacity drops.

Parameters:

element - The new element to be added.

Throws:

java.lang.InterruptedException - The thread that was waiting to add an element was interrupted.

removeElement

public final E removeElement()
                      throws java.lang.InterruptedException

This method removes the next element from the head of the queue. If the queue is empty, the method blocks until an element is available.

Returns:

The head element in the queue.

Throws:

java.lang.InterruptedException - The thread that was waiting to remove an element was interrupted.

getHead

public final E getHead()

This method returns a reference to the element at the head of the queue without removing the element from the queue.

Returns:

The head element in the queue, or null if the queue is empty.