queue : Java Glossary

Queue Classes

1.5

Java Queues classes and interfaces
Queue	interface	Basic queue interface. Defines the basic methods to add elements to the queue (offer, add), look at the head of the queue (peek, element) or pop the head of the queue off the queue (poll, remove). There are two versions of each method, e.g. offer returns a magic value on trouble, and add throws an Exception. Queue is derived from Collection so all the Collection methods are also available.
BlockingQueue	interface	If the queue is empty, blocks the current thread until some other thread adds an element. You can provide a timeout how long you are prepared to wait.
AbstractQueue	abstract class	Underpinnings for ArrayBlockingQueue, ConcurrentLinkedQueue, DelayQueue, LinkedBlockingQueue, PriorityBlockingQueue, PriorityQueue, SynchronousQueue.
ArrayBlockingQueue	class	FIFO blocking queue where the elements are stored in a fixed size array. The array buffer is circular, somtimes called a squirrel cage buffer or hamster buffer. When the array fills up it wraps around to the beginning being careful not to overwrite existing elements. If all goes well, the oldest elements are popped off in time to create room for new elements, hot on their heels.
ConcurrentLinkedQueue	class	Unbounded (can grow arbitrarily large), FIFO, thread-safe queue.
DelayQueue	class	Unbounded, sorted by delay, so that elements can be eligible to leave the queue once the delay has expired. The oldest expired delay element pops from the queue first.
Executors	class	creates thread pools that work off a todo queue.
LinkedBlockingQueue	class	Optionally bounded, FIFO blocking queue implemented with linked nodes.
LinkedList	class	Supports List interface, though it is very slow at indexing since it is implemented as linked nodes.
PriorityBlockingQueue	class	Blocking, sorted queue ordered by natural order Comparable interface or supplied Comparator. Does not permit null elements. Pops the smallest element.
PriorityQueue	class	Non-blocking, sorted queue ordered by natural order Comparable interface or supplied Comparator. Does not permit null elements. Pops the smallest element.
SynchronousQueue	class	A dummy queue that can’t even hold one element. Every add to the queue must be matched by an immediate pop before there can be another add. It is for thread to thread handoff.
ThreadPoolExecutor	class	executes each submitted task using one of possibly several pooled threads.

Java Queues classes and interfaces

Class

Type

Purpose

Queue

interface

Basic queue interface. Defines the basic methods to add elements to the queue (offer, add), look at the head of the queue (peek, element) or pop the head of the queue off the queue (poll, remove). There are two versions of each method, e.g. offer returns a magic value on trouble, and add throws an Exception. Queue is derived from Collection so all the Collection methods are also available.

BlockingQueue

interface

If the queue is empty, blocks the current thread until some other thread adds an element. You can provide a timeout how long you are prepared to wait.

AbstractQueue

abstract class

Underpinnings for ArrayBlockingQueue, ConcurrentLinkedQueue, DelayQueue, LinkedBlockingQueue, PriorityBlockingQueue, PriorityQueue, SynchronousQueue.

ArrayBlockingQueue

class

FIFO blocking queue where the elements are stored in a fixed size array. The array buffer is circular, somtimes called a squirrel cage buffer or hamster buffer. When the array fills up it wraps around to the beginning being careful not to overwrite existing elements. If all goes well, the oldest elements are popped off in time to create room for new elements, hot on their heels.

ConcurrentLinkedQueue

class

Unbounded (can grow arbitrarily large), FIFO, thread-safe queue.

DelayQueue

class

Unbounded, sorted by delay, so that elements can be eligible to leave the queue once the delay has expired. The oldest expired delay element pops from the queue first.

Executors

class

creates thread pools that work off a todo queue.

LinkedBlockingQueue

class

Optionally bounded, FIFO blocking queue implemented with linked nodes.

LinkedList

class

Supports List interface, though it is very slow at indexing since it is implemented as linked nodes.

PriorityBlockingQueue

class

Blocking, sorted queue ordered by natural order Comparable interface or supplied Comparator. Does not permit null elements. Pops the smallest element.

PriorityQueue

class

Non-blocking, sorted queue ordered by natural order Comparable interface or supplied Comparator. Does not permit null elements. Pops the smallest element.

SynchronousQueue

class

A dummy queue that can’t even hold one element. Every add to the queue must be matched by an immediate pop before there can be another add. It is for thread to thread handoff.

ThreadPoolExecutor

class

executes each submitted task using one of possibly several pooled threads.

Books

recommend book⇒Java Concurrency in Practice

by:

Brian Goetz, Tim Peierls, Joshua J. Bloch, Joseph Bowbeer, David Holmes, Doug Lea

978-0-321-34960-6

paperback

publisher:

Addison-Wesley

B004V9OA84

kindle

published:

2006-05-19

Bloch and Lea especially have very good reputations in concurrent programming. This is the dream team to write such a book.

Greyed out stores probably do not have the item in stock

recommend book⇒Concurrent Programming in Java(TM): Design Principles and Patterns, third edition

by:

Douglas Lea

978-0-321-25617-1

paperback

publisher:

Addison-Wesley

published:

2006-05-19

Threads and concurrency in Java, design considerations (safety, liveness, and performance), Before/After Patterns, layering, adapters, immutability and synchronization, deadlock, resource ordering, the Java Memory Model and concurrency, using the java.concurrency package, confinement, refactoring for concurrency, mutexes, read-write locks, recovering from failure, notifications, semaphores, latches, exchanges, transactions, one-way messages, worker threads, polling and event-driven I/O, parallelism techniques (fork/join, computation trees, and barriers), Communicating Sequential Processes (CSP).

Greyed out stores probably do not have the item in stock

Learning More

Oracle’s Javadoc on Queue interface : available:

on the web at Oracle.com
in the current JDK 1.7.0_04 or in the old JDK 1.6.0_32 on your local Windows J: drive.

Oracle’s Javadoc on java.util.concurrent package : available:

on the web at Oracle.com
in the current JDK 1.7.0_04 or in the old JDK 1.6.0_32 on your local Windows J: drive.

Oracle’s Javadoc on ThreadPoolExecutor class : available:

on the web at Oracle.com
in the current JDK 1.7.0_04 or in the old JDK 1.6.0_32 on your local Windows J: drive.

Oracle’s Javadoc on Executors class : available:

on the web at Oracle.com
in the current JDK 1.7.0_04 or in the old JDK 1.6.0_32 on your local Windows J: drive.

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queue : Java Glossary

Queue Classes

How to Use

Books

Learning More