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com.tangosol.util
Class SegmentedHashMap.Entry

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.SegmentedHashMap.Entry

All Implemented Interfaces:

Map.Entry

Direct Known Subclasses:

SegmentedConcurrentMap.LockableEntry

Enclosing class:

SegmentedHashMap

protected static class SegmentedHashMap.Entry

extends Base

implements Map.Entry

A map entry (key-value pair). The Map.entrySet method returns a collection-view of the map, whose elements are of this class.

Field Summary

protected SegmentedHashMap.Entry	m_eNext The next entry in the linked list (an open hashing implementation).
protected int	m_nHash The key's hash code.
protected Object	m_oKey The key.
protected Object	m_oValue The value.

Constructor Summary

protected

SegmentedHashMap.Entry(Object oKey, Object oValue, int nHash) Construct an Entry object with the specified key, value and hash.

Method Summary

boolean	equals(Object o) Compares the specified object with this entry for equality.
Object	getKey() Returns the key corresponding to this entry.
Object	getValue() Returns the value corresponding to this entry.
protected Object	getValueInternal() Returns the value corresponding to this entry, or NO_VALUE if this Entry is synthetid.
int	hashCode() Returns the hash code value for this map entry.
protected boolean	isSynthetic() Is this Entry synthetic?
protected SegmentedHashMap.Entry	nextEntry() Get the next non-synthetic entry in the linked list (open hash)
protected SegmentedHashMap.Entry	nextEntry(boolean fSynthetic) Get the next entry in the linked list (open hash).
protected void	setNext(SegmentedHashMap.Entry eNext) Set the next entry in the linked list (open hash)
Object	setValue(Object oValue) Replaces the value corresponding to this entry with the specified value (writes through to the map).
protected Object	setValueInternal(Object oValue) Replaces the value corresponding to this entry with the specified value (writes through to the map).
String	toString() Render the map entry as a String.

Field Detail

m_oKey

protected final Object m_oKey

The key. This object reference will not change for the life of the Entry.

m_oValue

protected volatile Object m_oValue

The value. This object reference can change within the life of the Entry. This field is declared volatile so that get() and put() can proceed without performing any synchronization.

m_nHash

protected final int m_nHash

The key's hash code. This value will not change for the life of the Entry.

m_eNext

protected volatile SegmentedHashMap.Entry m_eNext

The next entry in the linked list (an open hashing implementation). This field is declared volatile so the entry iterator can safely operate without performing any synchronization.

Constructor Detail

SegmentedHashMap.Entry

protected SegmentedHashMap.Entry(Object oKey,
                                 Object oValue,
                                 int nHash)

Construct an Entry object with the specified key, value and hash.

Parameters:

oKey - key with which the specified value is to be associated

oValue - value to be associated with the specified key

nHash - the hashCode for the specified key

Method Detail

getKey

public Object getKey()

Returns the key corresponding to this entry.

Specified by:

getKey in interface Map.Entry

Returns:

the key corresponding to this entry

getValue

public Object getValue()

Returns the value corresponding to this entry. If the mapping has been removed from the backing map (by the iterator's remove operation), the results of this call are undefined.

Specified by:

getValue in interface Map.Entry

Returns:

the value corresponding to this entry

getValueInternal

protected Object getValueInternal()

Returns the value corresponding to this entry, or NO_VALUE if this Entry is synthetid. If the mapping has been removed from the backing map (by the iterator's remove operation), the results of this call are undefined.

Returns:

the value corresponding to this entry, or NO_VALUE if the Entry is synthetic

setValue

public Object setValue(Object oValue)

Replaces the value corresponding to this entry with the specified value (writes through to the map). The behavior of this call is undefined if the mapping has already been removed from the map (by the iterator's remove operation).

Specified by:

setValue in interface Map.Entry

Parameters:

oValue - new value to be stored in this entry

Returns:

old value corresponding to the entry

setValueInternal

protected Object setValueInternal(Object oValue)

Replaces the value corresponding to this entry with the specified value (writes through to the map). The behavior of this call is undefined if the mapping has already been removed from the map.

Parameters:

oValue - new value to be stored in this entry

Returns:

old value corresponding to the entry, or NO_VALUE if the Entry was synthetic

equals

public boolean equals(Object o)

Compares the specified object with this entry for equality. Returns true if the given object is also a map entry and the two entries represent the same mapping. More formally, two entries e1 and e2 represent the same mapping if:

     (e1.getKey()==null ?
      e2.getKey()==null : e1.getKey().equals(e2.getKey())) &&
     (e1.getValue()==null ?
      e2.getValue()==null : e1.getValue().equals(e2.getValue()))
 

This ensures that the equals method works properly across different implementations of the Map.Entry interface.

Specified by:

equals in interface Map.Entry

Parameters:

o - object to be compared for equality with this map entry

Returns:

true if the specified object is equal to this map entry

hashCode

public int hashCode()

Returns the hash code value for this map entry. The hash code of a map entry e is defined to be:

     (e.getKey()==null   ? 0 : e.getKey().hashCode()) ^
     (e.getValue()==null ? 0 : e.getValue().hashCode())
 

This ensures that e1.equals(e2) implies that e1.hashCode()==e2.hashCode() for any two Entries e1 and e2, as required by the general contract of Object.hashCode.

Specified by:

hashCode in interface Map.Entry

Returns:

the hash code value for this map entry

See Also:

Object.hashCode(), Object.equals(Object), Map.Entry.equals(Object)

toString

public String toString()

Render the map entry as a String.

Returns:

the details about this entry

isSynthetic

protected boolean isSynthetic()

Is this Entry synthetic?

setNext

protected void setNext(SegmentedHashMap.Entry eNext)

Set the next entry in the linked list (open hash)

nextEntry

protected SegmentedHashMap.Entry nextEntry()

Get the next non-synthetic entry in the linked list (open hash)

Returns:

the next non-synthetic entry in the linked list

nextEntry

protected SegmentedHashMap.Entry nextEntry(boolean fSynthetic)

Get the next entry in the linked list (open hash). If fSynthetic is specified, also return synthetic Entry objects. Synethetic entries are Entry objects logically associated with a given key, but do not represent a key-value mapping in this map.

Parameters:

fSynthetic - include synthetic Entry objects?

Returns:

the next Entry in the linked list

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