org.erights.e.elib.tables
Class WeakValueMap

java.lang.Object
  |
  +--org.erights.e.elib.tables.EMap
        |
        +--org.erights.e.elib.tables.FlexMap
              |
              +--org.erights.e.elib.tables.WeakValueMap

All Implemented Interfaces:

EPrintable, Iteratable, Marker, PassByProxy, Persistent, Serializable

public class WeakValueMap

extends FlexMap

Untamed: A WeakValueMap is FlexMap whose values may be garbage collected.

A WeakValueMap acts as if an external entity (ie, the garbage collector) shares access to the map and occasionally decides to remove some elements. As a result, a WeakValueMap which isn't being changed by the program may nevertheless find itself shrinking over time. This external modifications can only occur 1) in their own turn, or 2) at the beginning of any operation that causes an enumeration.

The snapshot(), readOnly(), clone(), or diverge() of a WeakValueMap is not weak.

BUG: For some unfathomable reason, the actual values never seem to get collected, even though WeakValue by itself, when tested, seems to work fine.

XXX This class needs its own writeReplace() method.

Author:

Mark S. Miller

See Also:

java.util.WeakHashMap, Serialized Form

Field Summary

private FlexMap	myStuff
private Class	myValueType
(package private) static long	serialVersionUID

Fields inherited from class org.erights.e.elib.tables.EMap

Fields inherited from interface org.erights.e.elib.serial.PassByProxy

HONORARY, HONORED_NAMES

Fields inherited from interface org.erights.e.elib.serial.Persistent

HONORARY, HONORED_NAMES

Constructor Summary

WeakValueMap()
Enabled:

WeakValueMap(Class keyType, Class valueType)
Enabled:

Method Summary

void	__printOn(TextWriter out) Enabled: Does not remove garbage first, which is weird, but the other would be weirder.
Object	get(Object key, Object instead) Enabled: Does not remove garbage first, except for the value itself if it has been collected.
Object	getKeys(Class type) Enabled: Does *not* remove garbage first, which is dangerous.
Object	getValues(Class type) Enabled: Removes garbage first
Class	keyType() Enabled: Does not remove garbage first
void	put(Object key, Object value, boolean strict) Enabled: Does not remove garbage first.
void	removeAll() Enabled: Does not remove garbage first
void	removeKey(Object key, boolean strict) Enabled: Does not remove garbage first.
int	size() Enabled: Does *not* remove garbage first, but affected when garbage is removed.
Class	valueType() Enabled: Does not remove garbage first

Methods inherited from class org.erights.e.elib.tables.FlexMap

__optUncall, clone, domain, fromColumns, fromPairs, fromTypes, fromTypes, interning, interning, make, make, put, putAll, putAll, readOnly, removeKey, removeKeys, removeKeys, snapshot

Methods inherited from class org.erights.e.elib.tables.EMap

and, butNot, contains, diverge, diverge, extract, get, getKeys, getPair, getPair, getValues, intersects, iterate, maps, optExtract, or, or, printOn, sortKeys, sortKeys, sortValues, sortValues, toString, with, without

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

static final long serialVersionUID

myValueType

private final Class myValueType

myStuff

private final FlexMap myStuff

Constructor Detail

WeakValueMap

public WeakValueMap(Class keyType,
                    Class valueType)

Enabled:

WeakValueMap

public WeakValueMap()

Enabled:

Method Detail

size

public int size()

Enabled: Does *not* remove garbage first, but affected when garbage is removed.

Specified by:

size in class EMap

getKeys

public Object getKeys(Class type)

Enabled: Does *not* remove garbage first, which is dangerous.

When used in concert with getValues, be sure to call getValues first and hold on to the result when calling getKeys, so that none of the values will be become garbage between the two operations.

Or, better yet, just call getPair(), which is safe on all kinds of maps.

Specified by:

getKeys in class EMap

getValues

public Object getValues(Class type)

Enabled: Removes garbage first

Specified by:

getValues in class EMap

keyType

public Class keyType()

Enabled: Does not remove garbage first

Specified by:

keyType in class EMap

valueType

public Class valueType()

Enabled: Does not remove garbage first

Specified by:

valueType in class EMap

get

public Object get(Object key,
                  Object instead)

Enabled: Does not remove garbage first, except for the value itself if it has been collected.

Specified by:

get in class EMap

Parameters:

key - nullOk;

instead - nullOk;

Returns:

nullOk;

See Also:

org.erights.e.elib.ref.Ref#isSettled

put

public void put(Object key,
                Object value,
                boolean strict)

Enabled: Does not remove garbage first.

WeakValueMap doesn't support strict=true.

Specified by:

put in class FlexMap

See Also:

org.erights.e.elib.ref.Ref#isSettled

removeKey

public void removeKey(Object key,
                      boolean strict)

Enabled: Does not remove garbage first.

WeakValueMap doesn't support strict=true.

Specified by:

removeKey in class FlexMap

Parameters:

key - the key to remove

removeAll

public void removeAll()

Enabled: Does not remove garbage first

Specified by:

removeAll in class FlexMap

__printOn

public void __printOn(TextWriter out)
               throws IOException

Enabled: Does not remove garbage first, which is weird, but the other would be weirder.

Specified by:

__printOn in interface EPrintable

Overrides:

__printOn in class FlexMap

IOException