org.apache.commons.collections.map

Class AbstractReferenceMap.ReferenceEntry

Enclosing Class:
AbstractReferenceMap
Implemented Interfaces:
Map.Entry, KeyValue

protected static class AbstractReferenceMap.ReferenceEntry
extends AbstractHashedMap.HashEntry

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
parent
The parent map

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

hashCode, key, next, value

Constructor Summary

ReferenceEntry(AbstractReferenceMap parent, AbstractHashedMap.HashEntry next, int hashCode, Object key, Object value)
Creates a new entry object for the ReferenceMap.

Method Summary

boolean
equals(Object obj)
Compares this map entry to another.
Object
getKey()
Gets the key from the entry.
Object
getValue()
Gets the value from the entry.
int
hashCode()
Gets the hashcode of the entry using temporary hard references.
protected AbstractReferenceMap.ReferenceEntry
next()
Gets the next entry in the bucket.
Object
setValue(Object obj)
Sets the value of the entry.
protected Object
toReference(int type, Object 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

equals, getKey, getValue, hashCode, setValue, toString

Field Details

parent

protected final AbstractReferenceMap parent
The parent map

Constructor Details

ReferenceEntry

public ReferenceEntry(AbstractReferenceMap parent,
                      AbstractHashedMap.HashEntry next,
                      int hashCode,
                      Object key,
                      Object 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 Details

equals

public boolean equals(Object obj)
Compares this map entry to another.

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

Overrides:
equals in interface AbstractHashedMap.HashEntry
Parameters:
obj - the other map entry to compare to
Returns:
true if equal, false if not

getKey

public Object getKey()
Gets the key from the entry. This method dereferences weak and soft keys and thus may return null.
Specified by:
getKey in interface KeyValue
Overrides:
getKey in interface AbstractHashedMap.HashEntry
Returns:
the key, which may be null if it was garbage collected

getValue

public Object getValue()
Gets the value from the entry. This method dereferences weak and soft value and thus may return null.
Specified by:
getValue in interface KeyValue
Overrides:
getValue in interface AbstractHashedMap.HashEntry
Returns:
the value, which may be null if it was garbage collected

hashCode

public int hashCode()
Gets the hashcode of the entry using temporary hard references.

This implementation uses hashEntry on the main map.

Overrides:
hashCode in interface AbstractHashedMap.HashEntry
Returns:
the hashcode of the entry

next

protected AbstractReferenceMap.ReferenceEntry next()
Gets the next entry in the bucket.
Returns:
the next entry in the bucket

setValue

public Object setValue(Object obj)
Sets the value of the entry.
Overrides:
setValue in interface AbstractHashedMap.HashEntry
Parameters:
obj - the object to store
Returns:
the previous value

toReference

protected Object toReference(int type,
                             Object 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

Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.