xapi.collect.impl

Class SimpleFifo<E>

java.lang.Object

xapi.collect.impl.SimpleFifo<E>

Type Parameters:

E - - The type of item stores in the fifo

All Implemented Interfaces:

Serializable, Iterable<E>, Fifo<E>

public class SimpleFifo<E>
extends Object
implements Fifo<E>, Iterable<E>, Serializable

A simple, fast, threadsafe, one-way, single-linked list. This primitive collection eats nulls (ignores them on add), it will only return null from take() when it is empty, and it handles concurrency by synchronizing on a single object for the whole collection. A read in the middle of a write might get missed if the timing is very close, but no reads will be missed it you call take() until the fifo is drained.

Author:

"James X. Nelson (james@wetheinter.net)"

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	SimpleFifo.Node

Field Summary

Fields

Modifier and Type	Field and Description
protected SimpleFifo.Node	head

Constructor Summary

Constructors

Constructor and Description
SimpleFifo()
SimpleFifo(E[] els)

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all items in the queue.
boolean	contains(E item) Check if this queue contains the given item.
protected boolean	equals(E one, E two)
protected void	finalize()
Iterable<E>	forEach()
Fifo<E>	give(E item) Analagous to add(), however, we do not use the standard naming convention, to avoid interface clashes with adapter types in collection libraries that may wish to override our Fifo with their own type.
Fifo<E>	giveAll(E... elements) Analagous to addAll(), however, we avoid the standard naming convention, so we can provide a fluent, strongly typed api.
Fifo<E>	giveAll(Iterable<E> elements) Analagous to addAll(), however, we avoid the standard naming convention, so we can provide a fluent, strongly typed api.
boolean	isEmpty() Fastest way to tell if the queue is drained.
Iterator<E>	iterator()
String	join(String delim)
String	join(String delim, ConvertsValue<E,String> serializer)
boolean	remove(E item) Manually remove the item from queue.
protected String	serialize(ConvertsValue<E,String> serializer, E item)
int	size() Return a count of items in the queue.
E	take() Analagous to poll(); retrieves and removes head.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

head

protected SimpleFifo.Node head

Constructor Detail

SimpleFifo

public SimpleFifo()

SimpleFifo

public SimpleFifo(E[] els)

Method Detail

contains

public boolean contains(E item)

Description copied from interface: Fifo

Check if this queue contains the given item. O(n) performance. You may want to use a Set unless you know there aren't many items.

Specified by:

contains in interface Fifo<E>

Returns:

give

public Fifo<E> give(E item)

Description copied from interface: Fifo

Analagous to add(), however, we do not use the standard naming convention, to avoid interface clashes with adapter types in collection libraries that may wish to override our Fifo with their own type.

Specified by:

give in interface Fifo<E>

Parameters:

item - - The item to add to end of queue.

Returns:

this queue

clear

public void clear()

Description copied from interface: Fifo

Removes all items in the queue. head = tail;

Specified by:

clear in interface Fifo<E>

remove

public boolean remove(E item)

Description copied from interface: Fifo

Manually remove the item from queue. O(n) performance.

Specified by:

remove in interface Fifo<E>

Returns:

equals

protected boolean equals(E one,
                         E two)

take

public E take()

Description copied from interface: Fifo

Analagous to poll(); retrieves and removes head. We avoid the use of standard queue naming methods, in case an api to be injected uses Object instead of <Generic>

Specified by:

take in interface Fifo<E>

Returns:

and remove the head of the queue

size

public int size()

Description copied from interface: Fifo

Return a count of items in the queue. Default implementation uses a counter; subclasses may have O(n) if they must transverse the nodes to get a count.

Specified by:

size in interface Fifo<E>

Returns:

isEmpty

public boolean isEmpty()

Description copied from interface: Fifo

Fastest way to tell if the queue is drained.

Specified by:

isEmpty in interface Fifo<E>

Returns:

true if head == tail (there are no elements)

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

toString

public String toString()

Overrides:

toString in class Object

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Fifo<E>

Returns:

An iterator for the items in the queue. We do NOT implement Iterable, otherwise GWT JSOs will have a fit.

forEach

public Iterable<E> forEach()

Specified by:

forEach in interface Fifo<E>

Returns:

an Iterable for these items; JRE runtimes will likely return this; GWT runtimes will return an iterable object.

join

public String join(String delim)

Specified by:

join in interface Fifo<E>

join

public String join(String delim,
                   ConvertsValue<E,String> serializer)

serialize

protected String serialize(ConvertsValue<E,String> serializer,
                           E item)

giveAll

public Fifo<E> giveAll(E... elements)

Description copied from interface: Fifo

Analagous to addAll(), however, we avoid the standard naming convention, so we can provide a fluent, strongly typed api. Also, since the javascript object, JsFifo, is an array itself, the "cost" of the varargs is diminished because we can just 'cat them together.

Specified by:

giveAll in interface Fifo<E>

Parameters:

elements - - Varags or array adapters for bulk add.

Returns:

- this

giveAll

public Fifo<E> giveAll(Iterable<E> elements)

Description copied from interface: Fifo

Analagous to addAll(), however, we avoid the standard naming convention, so we can provide a fluent, strongly typed api.

Specified by:

giveAll in interface Fifo<E>

Parameters:

elements - - Any collection or custom iterable adapters (like blocking / async).

Returns:

- this