nars.storage
Class Bag<Type extends Item>

java.lang.Object
  nars.storage.Bag<Type>

Direct Known Subclasses:

ConceptBag, TaskBuffer, TaskLinkBag, TermLinkBag

public abstract class Bag<Type extends Item>
extends java.lang.Object

A Bag is a storage with a constant capacity and maintains an internal priority distribution for retrieval.

Each entity in a bag must extend Item, which has a BudgetValue and a key.

A name table is used to merge duplicate items that have the same key.

The bag space is divided by a threshold, above which is mainly time management, and below, space mamagement. Differences: (1) level selection vs. item selection, (2) decay rate

Field Summary

protected int	capacity defined in different bags
protected int	currentCounter maximum number of items to be taken out at current level
protected int	currentLevel current take out level
(package private) static Distributor	DISTRIBUTOR shared distributor that produce the probability distribution
protected java.util.ArrayList<Type>[]	itemTable array of lists of items, for items on different level
protected int	levelIndex index to get next level, kept in individual objects
protected static float	LOAD_FACTOR hashtable load factor
protected int	mass current sum of occupied level
protected java.util.HashMap<java.lang.String,Type>	nameTable mapping from key to item
protected static float	RELATIVE_THRESHOLD relative threshold, only calculate once
protected boolean	showing whether this bag has an active window
protected static int	THRESHOLD firing threshold
protected static int	TOTAL_LEVEL priority levels
protected BagWindow	window display window

Constructor Summary

protected

Bag() constructor, called from subclasses

Method Summary

float	averagePriority() Get the average priority of Items
protected abstract int	capacity() To get the capacity of the concrete subclass
boolean	contains(Type it) Check if an item is in the bag
private boolean	emptyLevel(int n) Check whether a level is empty
protected abstract int	forgetRate() Get the item decay rate, which differs in difference subclass, and can be changed in run time by the user, so not a constant.
Type	get(java.lang.String key) Get an Item by key
private int	getLevel(Type item) Decide the put-in level according to priority
private Type	intoBase(Type newItem) Insert an item into the itemTable, and return the overflow
protected void	outOfBase(Type oldItem) Remove an item from itemTable, then adjust mass
Type	pickOut(java.lang.String key) Pick an item by key, then remove it from the bag
void	play() Resume display
void	putBack(Type oldItem) Put an item back into the itemTable
void	putIn(Type newItem) Add a new Item into the Bag
void	refresh() Refresh display
void	startPlay(java.lang.String title) To start displaying the Bag in a BagWindow
void	stop() Stop display
Type	takeOut() Choose an Item according to priority distribution and take it out of the Bag
private Type	takeOutFirst(int level) Take out the first or last Type in a level from the itemTable
java.lang.String	toString() Collect Bag content into a String for display

Methods inherited from class java.lang.Object

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

Field Detail

TOTAL_LEVEL

protected static final int TOTAL_LEVEL

priority levels

See Also:

Constant Field Values

THRESHOLD

protected static final int THRESHOLD

firing threshold

See Also:

Constant Field Values

RELATIVE_THRESHOLD

protected static final float RELATIVE_THRESHOLD

relative threshold, only calculate once

See Also:

Constant Field Values

LOAD_FACTOR

protected static final float LOAD_FACTOR

hashtable load factor

See Also:

Constant Field Values

DISTRIBUTOR

static final Distributor DISTRIBUTOR

shared distributor that produce the probability distribution

nameTable

protected java.util.HashMap<java.lang.String,Type extends Item> nameTable

mapping from key to item

itemTable

protected java.util.ArrayList<Type extends Item>[] itemTable

array of lists of items, for items on different level

capacity

protected int capacity

defined in different bags

mass

protected int mass

current sum of occupied level

levelIndex

protected int levelIndex

index to get next level, kept in individual objects

currentLevel

protected int currentLevel

current take out level

currentCounter

protected int currentCounter

maximum number of items to be taken out at current level

showing

protected boolean showing

whether this bag has an active window

window

protected BagWindow window

display window

Constructor Detail

Bag

protected Bag()

constructor, called from subclasses

Method Detail

capacity

protected abstract int capacity()

To get the capacity of the concrete subclass

Returns:

Bag capacity, in number of Items allowed

forgetRate

protected abstract int forgetRate()

Get the item decay rate, which differs in difference subclass, and can be changed in run time by the user, so not a constant.

Returns:

The number of times for a decay factor to be fully applied

averagePriority

public float averagePriority()

Get the average priority of Items

Returns:

The average priority of Items in the bag

contains

public boolean contains(Type it)

Check if an item is in the bag

Parameters:

it - An item

Returns:

Whether the Item is in the Bag

get

public Type get(java.lang.String key)

Get an Item by key

Parameters:

key - The key of the Item

Returns:

The Item with the given key

putIn

public void putIn(Type newItem)

Add a new Item into the Bag

Parameters:

newItem - The new Item

putBack

public void putBack(Type oldItem)

Put an item back into the itemTable

The only place where the forgetting rate is applied

Parameters:

oldItem - The Item to put back

takeOut

public Type takeOut()

Choose an Item according to priority distribution and take it out of the Bag

Returns:

The selected Item

pickOut

public Type pickOut(java.lang.String key)

Pick an item by key, then remove it from the bag

Parameters:

key - The given key

Returns:

The Item with the key

emptyLevel

private boolean emptyLevel(int n)

Check whether a level is empty

Parameters:

n - The level index

Returns:

Whether that level is empty

getLevel

private int getLevel(Type item)

Decide the put-in level according to priority

Parameters:

item - The Item to put in

Returns:

The put-in level

intoBase

private Type intoBase(Type newItem)

Insert an item into the itemTable, and return the overflow

Parameters:

newItem - The Item to put in

Returns:

The overflow Item

takeOutFirst

private Type takeOutFirst(int level)

Take out the first or last Type in a level from the itemTable

Parameters:

level - The current level

Returns:

The first Item

outOfBase

protected void outOfBase(Type oldItem)

Remove an item from itemTable, then adjust mass

Parameters:

oldItem - The Item to be removed

startPlay

public void startPlay(java.lang.String title)

To start displaying the Bag in a BagWindow

Parameters:

title - The title of the window

play

public void play()

Resume display

refresh

public void refresh()

Refresh display

stop

public void stop()

Stop display

toString

public java.lang.String toString()

Collect Bag content into a String for display

Overrides:

toString in class java.lang.Object