org.apache.commons.collections.map
Class AbstractReferenceMap.ReferenceEntry<K,V>

java.lang.Object
  org.apache.commons.collections.map.AbstractHashedMap.HashEntry<K,V>
      org.apache.commons.collections.map.AbstractReferenceMap.ReferenceEntry<K,V>

All Implemented Interfaces:

Map.Entry<K,V>, KeyValue<K,V>

Enclosing class:

AbstractReferenceMap<K,V>

protected static class AbstractReferenceMap.ReferenceEntry<K,V>
extends AbstractHashedMap.HashEntry<K,V>

A MapEntry implementation for the map.

If getKey() or getValue() returns null, it means the mapping is stale and should be removed.

Since:

Commons Collections 3.1

Field Summary

protected AbstractReferenceMap<K,V>	parent The parent map
protected Reference<K>	refKey
protected Reference<V>	refValue

Fields inherited from class org.apache.commons.collections.map.AbstractHashedMap.HashEntry

hashCode, next

Constructor Summary

AbstractReferenceMap.ReferenceEntry(AbstractReferenceMap<K,V> parent, AbstractReferenceMap.ReferenceEntry<K,V> next, int hashCode, K key, V value)
Creates a new entry object for the ReferenceMap.

Method Summary

boolean	equals(Object obj) Compares this map entry to another.
K	getKey() Gets the key from the entry.
V	getValue() Gets the value from the entry.
int	hashCode() Gets the hashcode of the entry using temporary hard references.
protected AbstractReferenceMap.ReferenceEntry<K,V>	next() Gets the next entry in the bucket.
V	setValue(V obj) Sets the value of the entry.
protected <T> Reference<T>	toReference(int type, T referent, int hash) Constructs a reference of the given type to the given referent.

Methods inherited from class org.apache.commons.collections.map.AbstractHashedMap.HashEntry

setKey, toString

Methods inherited from class java.lang.Object

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

Field Detail

parent

protected final AbstractReferenceMap<K,V> parent

The parent map

refKey

protected Reference<K> refKey

refValue

protected Reference<V> refValue

Constructor Detail

AbstractReferenceMap.ReferenceEntry

public AbstractReferenceMap.ReferenceEntry(AbstractReferenceMap<K,V> parent,
                                           AbstractReferenceMap.ReferenceEntry<K,V> next,
                                           int hashCode,
                                           K key,
                                           V value)

Creates a new entry object for the ReferenceMap.

Parameters:

parent - the parent map

next - the next entry in the hash bucket

hashCode - the hash code of the key

key - the key

value - the value

Method Detail

getKey

public K getKey()

Gets the key from the entry. This method dereferences weak and soft keys and thus may return null.

Specified by:

getKey in interface Map.Entry<K,V>

Specified by:

getKey in interface KeyValue<K,V>

Overrides:

getKey in class AbstractHashedMap.HashEntry<K,V>

Returns:

the key, which may be null if it was garbage collected

getValue

public V getValue()

Gets the value from the entry. This method dereferences weak and soft value and thus may return null.

Specified by:

getValue in interface Map.Entry<K,V>

Specified by:

getValue in interface KeyValue<K,V>

Overrides:

getValue in class AbstractHashedMap.HashEntry<K,V>

Returns:

the value, which may be null if it was garbage collected

setValue

public V setValue(V obj)

Sets the value of the entry.

Specified by:

setValue in interface Map.Entry<K,V>

Overrides:

setValue in class AbstractHashedMap.HashEntry<K,V>

Parameters:

obj - the object to store

Returns:

the previous value

equals

public boolean equals(Object obj)

Compares this map entry to another.

This implementation uses isEqualKey and isEqualValue on the main map for comparison.

Specified by:

equals in interface Map.Entry<K,V>

Overrides:

equals in class AbstractHashedMap.HashEntry<K,V>

Parameters:

obj - the other map entry to compare to

Returns:

true if equal, false if not

hashCode

public int hashCode()

Gets the hashcode of the entry using temporary hard references.

This implementation uses hashEntry on the main map.

Specified by:

hashCode in interface Map.Entry<K,V>

Overrides:

hashCode in class AbstractHashedMap.HashEntry<K,V>

Returns:

the hashcode of the entry

toReference

protected <T> Reference<T> toReference(int type,
                                       T referent,
                                       int hash)

Constructs a reference of the given type to the given referent. The reference is registered with the queue for later purging.

Parameters:

type - HARD, SOFT or WEAK

referent - the object to refer to

hash - the hash code of the key of the mapping; this number might be different from referent.hashCode() if the referent represents a value and not a key

next

protected AbstractReferenceMap.ReferenceEntry<K,V> next()

Gets the next entry in the bucket.

Returns:

the next entry in the bucket