Package gnu.kawa.util

Class AbstractWeakHashTable<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

gnu.kawa.util.AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

gnu.kawa.util.AbstractWeakHashTable<K,V>

All Implemented Interfaces:

Map<K,V>

public abstract class AbstractWeakHashTable<K,V>
extends AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

A hash table with weakly referenced keys and values. Unlike java.util.WeakHashMap, this is useful when a value object contain a strong reference to the corresponding keys.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AbstractWeakHashTable.WEntry<K,V>

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K extends Object,V extends Object>, AbstractMap.SimpleImmutableEntry<K extends Object,V extends Object>

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Field Summary

Fields inherited from class gnu.kawa.util.AbstractHashTable

DEFAULT_INITIAL_SIZE, mask, num_bindings, table

Constructor Summary

Constructors

Constructor	Description
AbstractWeakHashTable()
AbstractWeakHashTable(int capacity)

Method Summary

Modifier and Type	Method	Description
protected AbstractWeakHashTable.WEntry<K,V>[]	allocEntries(int n)	Allocate Entry[n].
protected void	cleanup()
V	get(Object key, V defaultValue)	Find value for given key.
protected int	getEntryHashCode(AbstractWeakHashTable.WEntry<K,V> entry)	Extract hash-code from Entry.
protected AbstractWeakHashTable.WEntry<K,V>	getEntryNext(AbstractWeakHashTable.WEntry<K,V> entry)	Extract next Entry in same hash-bucket.
protected abstract K	getKeyFromValue(V value)
protected V	getValueIfMatching(AbstractWeakHashTable.WEntry<K,V> node, Object key)
int	hash(Object key)	Calculate hash code of a key.
protected AbstractWeakHashTable.WEntry<K,V>	makeEntry(K key, int hash, V value)	Allocate a new node in the hash table.
V	put(K key, V value)
protected void	setEntryNext(AbstractWeakHashTable.WEntry<K,V> entry, AbstractWeakHashTable.WEntry<K,V> next)	Set next Entry in same hash-bucket.
protected boolean	valuesEqual(V oldValue, V newValue)

Methods inherited from class gnu.kawa.util.AbstractHashTable

clear, entrySet, get, getNode, getOrDefault, hashToIndex, matches, matches, put, rehash, remove, size

Methods inherited from class java.util.AbstractMap

clone, containsKey, containsValue, equals, hashCode, isEmpty, keySet, putAll, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

AbstractWeakHashTable

public AbstractWeakHashTable()

AbstractWeakHashTable

public AbstractWeakHashTable(int capacity)

Method Detail

getKeyFromValue

protected abstract K getKeyFromValue(V value)

getEntryHashCode

protected int getEntryHashCode(AbstractWeakHashTable.WEntry<K,V> entry)

Description copied from class: AbstractHashTable

Extract hash-code from Entry.

Specified by:

getEntryHashCode in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

getEntryNext

protected AbstractWeakHashTable.WEntry<K,V> getEntryNext(AbstractWeakHashTable.WEntry<K,V> entry)

Description copied from class: AbstractHashTable

Extract next Entry in same hash-bucket.

Specified by:

getEntryNext in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

setEntryNext

protected void setEntryNext(AbstractWeakHashTable.WEntry<K,V> entry,
                            AbstractWeakHashTable.WEntry<K,V> next)

Description copied from class: AbstractHashTable

Set next Entry in same hash-bucket.

Specified by:

setEntryNext in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

allocEntries

protected AbstractWeakHashTable.WEntry<K,V>[] allocEntries(int n)

Description copied from class: AbstractHashTable

Allocate Entry[n].

Specified by:

allocEntries in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

getValueIfMatching

protected V getValueIfMatching(AbstractWeakHashTable.WEntry<K,V> node,
                               Object key)

get

public V get(Object key,
             V defaultValue)

Description copied from class: AbstractHashTable

Find value for given key. Return defaultValue if not found.

Overrides:

get in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

hash

public int hash(Object key)

Description copied from class: AbstractHashTable

Calculate hash code of a key.

Overrides:

hash in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

valuesEqual

protected boolean valuesEqual(V oldValue,
                              V newValue)

makeEntry

protected AbstractWeakHashTable.WEntry<K,V> makeEntry(K key,
                                                            int hash,
                                                            V value)

Description copied from class: AbstractHashTable

Allocate a new node in the hash table.

Specified by:

makeEntry in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

put

public V put(K key,
             V value)

Specified by:

put in interface Map<K,V>

Overrides:

put in class AbstractHashTable<AbstractWeakHashTable.WEntry<K,V>,K,V>

cleanup

protected void cleanup()