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 Map.Entry.

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

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

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(java.util.Map.Entry entry)
Constructs a new pair from the specified Map.Entry.

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

Method Summary

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

java.lang.NullPointerException - if the entry is null

DefaultKeyValue

public DefaultKeyValue(java.util.Map.Entry entry)

Constructs a new pair from the specified Map.Entry.

Parameters:

entry - the entry to copy, must not be null

Throws:

java.lang.NullPointerException - if the entry is null

Method Detail

setKey

public java.lang.Object setKey(java.lang.Object key)

Sets the key.

Parameters:

key - the new key

Returns:

the old key

Throws:

java.lang.IllegalArgumentException - if key is this object

setValue

public java.lang.Object setValue(java.lang.Object value)

Sets the value.

Parameters:

value - the new value

Returns:

the old value of the value

Throws:

java.lang.IllegalArgumentException - if value is this object

toMapEntry

public java.util.Map.Entry toMapEntry()

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

Returns:

a MapEntry instance

equals

public boolean equals(java.lang.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 java.lang.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 java.lang.Object

Returns:

a suitable hash code