structure
Class Association

java.lang.Object
  structure.Association

All Implemented Interfaces:

Map.Entry

Direct Known Subclasses:

ComparableAssociation

public class Association
extends Object
implements Map.Entry

A class implementing a key-value pair. This class associates an immutable key with a mutable value. Used in many other structures.

Constructor Summary

Association(Object key)
Constructs a pair from a key; value is null.

Association(Object key, Object value)
Constructs a pair from a key and value.

Method Summary

boolean	equals(Object other) Standard comparison function.
Object	getKey() Fetch key from association.
Object	getValue() Fetch value from association.
int	hashCode() Standard hashcode function.
Object	setValue(Object value) Sets the value of the key-value pair.
String	toString() Standard string representation of an association.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Association

public Association(Object key,
                   Object value)

Constructs a pair from a key and value.

Parameters:

key - A non-null object.

value - A (possibly null) object.

Association

public Association(Object key)

Constructs a pair from a key; value is null.

Parameters:

key - A non-null key value.

Method Detail

equals

public boolean equals(Object other)

Standard comparison function. Comparison based on keys only.

Specified by:

equals in interface Map.Entry

Overrides:

equals in class Object

Parameters:

other - Another association.

Returns:

true iff the keys are equal.

hashCode

public int hashCode()

Standard hashcode function.

Specified by:

hashCode in interface Map.Entry

Overrides:

hashCode in class Object

Returns:

A hash code for association.

See Also:

Hashtable

getValue

public Object getValue()

Fetch value from association. May return null.

Specified by:

getValue in interface Map.Entry

Returns:

The value field of the association.

getKey

public Object getKey()

Fetch key from association. Should not return null.

Specified by:

getKey in interface Map.Entry

Returns:

Key of the key-value pair.

setValue

public Object setValue(Object value)

Sets the value of the key-value pair.

Specified by:

setValue in interface Map.Entry

Parameters:

value - The new value.

toString

public String toString()

Standard string representation of an association.

Overrides:

toString in class Object

Returns:

String representing key-value pair.