xapi.collect.api

Interface Fifo<E>

Type Parameters:

E -

All Known Implementing Classes:

SimpleFifo

public interface Fifo<E>

A simple fifo interface, for lightweight collections support. It's a simply First in, first out linked queue. For the sake of trim code, and aiding in gwt compiler optimization, our core library should not use java.util, nor other collections framework. This is so gwt code doesn't take a codesize hit for using the tool. Jre-only code is free to use any framework. The default implementaion, SimpleFifo is threadsafe; explicitly single-threaded environments may want to override this in places where a Fifo is injected (core libraries just use new SimpleFifo). GWT just uses an overlay on a native [] to implement fifo. This collection will only throw exceptions if you are doing something illegal, like using Iterator.remove() before calling .next(). null adds are silently ignored, and take() will only return null if the fifo is drained. This is so subclasses can override isEmpty() to return false until a given resource is closed, or a set of Future<>s complete. take() can return null while isEmpty return false.

Author:

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

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.
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)
boolean	remove(E item) Manually remove the item from queue.
int	size() Return a count of items in the queue.
E	take() Analagous to poll(); retrieves and removes head.

Method Detail

give

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.

Parameters:

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

Returns:

this queue

giveAll

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

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.

Parameters:

elements - - Varags or array adapters for bulk add.

Returns:

- this

giveAll

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.

Parameters:

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

Returns:

- this

take

E take()

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>

Returns:

and remove the head of the queue

isEmpty

boolean isEmpty()

Fastest way to tell if the queue is drained.

Returns:

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

contains

boolean contains(E item)

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.

Parameters:

item -

Returns:

remove

boolean remove(E item)

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

Parameters:

item -

Returns:

size

int size()

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.

Returns:

clear

void clear()

Removes all items in the queue. head = tail;

iterator

Iterator<E> iterator()

Returns:

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

forEach

Iterable<E> forEach()

Returns:

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

join

String join(String delim)