org.apache.commons.collections.keyvalue
Class DefaultKeyValue<K,V>

java.lang.Object
  org.apache.commons.collections.keyvalue.AbstractKeyValue<K,V>
      org.apache.commons.collections.keyvalue.DefaultKeyValue<K,V>

All Implemented Interfaces:

KeyValue<K,V>

public class DefaultKeyValue<K,V>
extends AbstractKeyValue<K,V>

A mutable KeyValue pair that does not implement MapEntry.

Note that a DefaultKeyValue instance may not contain itself as a key or value.

Since:

Commons Collections 3.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:35:07 $

Author:

James Strachan, Michael A. Smith, Neil O'Toole, Matt Hall, John Watkinson, Stephen Colebourne

Field Summary

Fields inherited from class org.apache.commons.collections.keyvalue.AbstractKeyValue

key, value

Constructor Summary

DefaultKeyValue()
Constructs a new pair with a null key and null value.

DefaultKeyValue(KeyValue<K,V> pair)
Constructs a new pair from the specified KeyValue.

DefaultKeyValue(K key, V value)
Constructs a new pair with the specified key and given value.

DefaultKeyValue(Map.Entry<K,V> entry)
Constructs a new pair from the specified MapEntry.

Method Summary

boolean	equals(Object obj) Compares this Map Entry with another Map Entry.
int	hashCode() Gets a hashCode compatible with the equals method.
K	setKey(K key) Sets the key.
V	setValue(V value) Sets the value.
Map.Entry<K,V>	toMapEntry() Returns a new Map.Entry object with key and value from this pair.

Methods inherited from class org.apache.commons.collections.keyvalue.AbstractKeyValue

getKey, getValue, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultKeyValue

public DefaultKeyValue()

Constructs a new pair with a null key and null value.

DefaultKeyValue

public DefaultKeyValue(K key,
                       V value)

Constructs a new pair with the specified key and given value.

Parameters:

key - the key for the entry, may be null

value - the value for the entry, may be null

DefaultKeyValue

public DefaultKeyValue(KeyValue<K,V> pair)

Constructs a new pair from the specified KeyValue.

Parameters:

pair - the pair to copy, must not be null

Throws:

NullPointerException - if the entry is null

DefaultKeyValue

public DefaultKeyValue(Map.Entry<K,V> entry)

Constructs a new pair from the specified MapEntry.

Parameters:

entry - the entry to copy, must not be null

Throws:

NullPointerException - if the entry is null

Method Detail

setKey

public K setKey(K key)

Sets the key.

Parameters:

key - the new key

Returns:

the old key

Throws:

IllegalArgumentException - if key is this object

setValue

public V setValue(V value)

Sets the value.

Parameters:

value - the new value

Returns:

the old value of the value

Throws:

IllegalArgumentException - if value is this object

toMapEntry

public Map.Entry<K,V> toMapEntry()

Returns a new Map.Entry object with key and value from this pair.

Returns:

a MapEntry instance

equals

public boolean equals(Object obj)

Compares this Map Entry with another Map Entry.

Returns true if the compared object is also a DefaultKeyValue, and its key and value are equal to this object's key and value.

Overrides:

equals in class Object

Parameters:

obj - the object to compare to

Returns:

true if equal key and value

hashCode

public int hashCode()

Gets a hashCode compatible with the equals method.

Implemented per API documentation of Map.Entry.hashCode(), however subclasses may override this.

Overrides:

hashCode in class Object

Returns:

a suitable hash code