Package org.mozilla.javascript

Class SlotMapContainer

java.lang.Object

org.mozilla.javascript.SlotMapContainer

All Implemented Interfaces:

Iterable<Slot>, SlotMap

Direct Known Subclasses:

ThreadSafeSlotMapContainer

class SlotMapContainer
extends Object
implements SlotMap

This class holds the various SlotMaps of various types, and knows how to atomically switch between them when we need to so that we use the right data structure at the right time.

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	DEFAULT_SIZE
private static final int	LARGE_HASH_SIZE	Once the object has this many properties in it, we will replace the EmbeddedSlotMap with HashSlotMap.
protected SlotMap	map

Constructor Summary

Constructors

Constructor	Description
SlotMapContainer()
SlotMapContainer(int initialSize)

Method Summary

Modifier and Type	Method	Description
void	add(Slot newSlot)	Insert a new slot to the map.
protected void	checkMapSize()	Before inserting a new item in the map, check and see if we need to expand from the embedded map to a HashMap that is more robust against large numbers of hash collisions.
int	dirtySize()
boolean	isEmpty()	Return whether the map is empty.
Iterator<Slot>	iterator()
Slot	modify(Object key, int index, int attributes)	Return the Slot that matches EITHER "key" or "index".
Slot	query(Object key, int index)	Retrieve the slot at EITHER key or index, or return null if the slot cannot be found.
long	readLock()
void	remove(Object key, int index)	Remove the slot at either "key" or "index".
void	replace(Slot oldSlot, Slot newSlot)	Replace "slot" with a new slot.
int	size()	Return the size of the map.
void	unlockRead(long stamp)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

LARGE_HASH_SIZE

private static final int LARGE_HASH_SIZE

Once the object has this many properties in it, we will replace the EmbeddedSlotMap with HashSlotMap. We can adjust this parameter to balance performance for typical objects versus performance for huge objects with many collisions.

See Also:

• Constant Field Values

DEFAULT_SIZE

private static final int DEFAULT_SIZE

See Also:

• Constant Field Values

map

protected SlotMap map

Constructor Details

SlotMapContainer

SlotMapContainer()

SlotMapContainer

SlotMapContainer(int initialSize)

Method Details

size

public int size()

Description copied from interface: SlotMap

Return the size of the map.

Specified by:

size in interface SlotMap

dirtySize

public int dirtySize()

isEmpty

public boolean isEmpty()

Description copied from interface: SlotMap

Return whether the map is empty.

Specified by:

isEmpty in interface SlotMap

modify

public Slot modify(Object key,
 int index,
 int attributes)

Description copied from interface: SlotMap

Return the Slot that matches EITHER "key" or "index". (It will use "key" if it is not null, and otherwise "index".) If no slot exists, then create a default slot class.

Specified by:

modify in interface SlotMap

Parameters:

key - The key for the slot, which should be a String or a Symbol.

index - if key is zero, then this will be used as the key instead.

attributes - the attributes to be set on the slot if a new slot is created. Existing slots will not be modified.

Returns:

a Slot, which will be created anew if no such slot exists.

replace

public void replace(Slot oldSlot,
 Slot newSlot)

Description copied from interface: SlotMap

Replace "slot" with a new slot. This is used to change slot types.

Specified by:

replace in interface SlotMap

query

public Slot query(Object key,
 int index)

Description copied from interface: SlotMap

Retrieve the slot at EITHER key or index, or return null if the slot cannot be found.

Specified by:

query in interface SlotMap

Parameters:

key - The key for the slot, which should be a String or a Symbol.

index - if key is zero, then this will be used as the key instead.

Returns:

either the Slot that matched the key and index, or null

add

public void add(Slot newSlot)

Description copied from interface: SlotMap

Insert a new slot to the map. Both "name" and "indexOrHash" must be populated. Note that ScriptableObject generally adds slots via the "modify" method.

Specified by:

add in interface SlotMap

remove

public void remove(Object key,
 int index)

Description copied from interface: SlotMap

Remove the slot at either "key" or "index".

Specified by:

remove in interface SlotMap

Parameters:

key - The key for the slot, which should be a String or a Symbol.

index - if key is zero, then this will be used as the key instead.

iterator

public Iterator<Slot> iterator()

Specified by:

iterator in interface Iterable<Slot>

readLock

public long readLock()

unlockRead

public void unlockRead(long stamp)

checkMapSize

protected void checkMapSize()

Before inserting a new item in the map, check and see if we need to expand from the embedded map to a HashMap that is more robust against large numbers of hash collisions.