com.tangosol.util
Class SimpleMapEntry

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.SimpleMapEntry

All Implemented Interfaces:

Serializable, Cloneable, Map.Entry

Direct Known Subclasses:

AbstractKeyBasedMap.EntrySet.Entry, BinaryMap.Entry, ReadWriteBackingMap.WriteQueue.Entry, SimpleElement.AttributeMap.Entry

public class SimpleMapEntry
extends Base
implements Map.Entry, Cloneable, Serializable

A map entry (key-value pair). The Map.entrySet method returns a collection-view of the map, whose elements are of this class. The only way to obtain a reference to a map entry is from the iterator of this collection-view. These Map.Entry objects are valid only for the duration of the iteration; more formally, the behavior of a map entry is undefined if the backing map has been modified after the entry was returned by the iterator, except through the iterator's own remove operation, or through the setValue operation on a map entry returned by the iterator.

Author:

cp 2002.02.07

Field Summary

protected Object	m_oKey The key.
protected Object	m_oValue The value.

Constructor Summary

protected	SimpleMapEntry() Default constructor.
	SimpleMapEntry(Map.Entry entry) Copy constructor.
protected	SimpleMapEntry(Object oKey) Construct a SimpleMapEntry with just a key.
	SimpleMapEntry(Object oKey, Object oValue) Construct a SimpleMapEntry with a key and a value.

Method Summary

Object	clone() Clone the Entry.
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.
int	hashCode() Returns the hash code value for this map entry.
Object	setValue(Object oValue) Replaces the value corresponding to this entry with the specified value (optional operation).
String	toString() Render the map entry as a String.

Field Detail

m_oKey

protected Object m_oKey

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

m_oValue

protected Object m_oValue

The value. This object reference can change within the life of the Entry.

Constructor Detail

SimpleMapEntry

protected SimpleMapEntry()

Default constructor.

SimpleMapEntry

protected SimpleMapEntry(Object oKey)

Construct a SimpleMapEntry with just a key.

Parameters:

oKey - an object for the key

SimpleMapEntry

public SimpleMapEntry(Map.Entry entry)

Copy constructor.

Parameters:

entry - an entry to copy from

SimpleMapEntry

public SimpleMapEntry(Object oKey,
                      Object oValue)

Construct a SimpleMapEntry with a key and a value.

Parameters:

oKey - an object for the key

oValue - an object for the value

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.

setValue

public Object setValue(Object oValue)

Replaces the value corresponding to this entry with the specified value (optional operation). (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

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.

toString

public String toString()

Render the map entry as a String.

Returns:

the details about this entry

clone

public Object clone()

Clone the Entry.

Returns:

a clone of this Entry