org.apache.commons.collections.keyvalue
Class DefaultKeyValue

java.lang.Object
  |
  +--org.apache.commons.collections.keyvalue.AbstractKeyValue
        |
        +--org.apache.commons.collections.keyvalue.DefaultKeyValue

All Implemented Interfaces:

KeyValue

public class DefaultKeyValue

extends AbstractKeyValue

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: 1.4 $ $Date: 2004/02/18 01:00:08 $

Author:

James Strachan, Michael A. Smith, Neil O'Toole, 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 pair)
Constructs a new pair from the specified KeyValue.

DefaultKeyValue(Map.Entry entry)
Constructs a new pair from the specified MapEntry.

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

Method Summary

boolean	equals(Object obj) Compares this Map Entry with another Map Entry.
int	hashCode() Gets a hashCode compatible with the equals method.
Object	setKey(Object key) Sets the key.
Object	setValue(Object value) Sets the value.
Map.Entry	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(Object key,
                       Object 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 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 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 Object setKey(Object key)

Sets the key.

Parameters:

key - the new key

Returns:

the old key

Throws:

IllegalArgumentException - if key is this object

setValue

public Object setValue(Object 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 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