java.util
Class Dictionary<K,V>
A Dictionary maps keys to values;
how it does that is
implementation-specific.
This is an abstract class which has really gone by the wayside.
People at Javasoft are probably embarrassed by it. At this point,
it might as well be an interface rather than a class, but it remains
this poor, laughable skeleton for the sake of backwards compatibility.
At any rate, this was what came before the
Map interface
in the Collections framework.
Dictionary()- Sole constructor (often called implicitly).
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abstract Enumeration | elements()- Returns an Enumeration of the values in this Dictionary.
|
abstract V | get(Object key)- Returns the value associated with the supplied key, or null
if no such value exists.
|
abstract boolean | isEmpty()- Returns true when there are no elements in this Dictionary.
|
abstract Enumeration | keys()- Returns an Enumeration of the keys in this Dictionary
|
abstract V | put(K key, V value)- Inserts a new value into this Dictionary, located by the
supplied key.
|
abstract V | remove(Object key)- Removes from the Dictionary the value located by the given key.
|
abstract int | size()- Returns the number of values currently in this Dictionary.
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clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
Dictionary
public Dictionary()
Sole constructor (often called implicitly).
elements
public abstract Enumeration elements()
Returns an Enumeration of the values in this Dictionary.
- an Enumeration of the values
get
public abstract V get(Object key)
Returns the value associated with the supplied key, or null
if no such value exists. Since Dictionaries are not allowed null keys
or elements, a null result always means the key is not present.
key - the key to use to fetch the value
isEmpty
public abstract boolean isEmpty()
Returns true when there are no elements in this Dictionary.
keys
public abstract Enumeration keys()
Returns an Enumeration of the keys in this Dictionary
- an Enumeration of the keys
put
public abstract V put(K key,
V value) Inserts a new value into this Dictionary, located by the
supplied key. Dictionary does not support null keys or values, so
a null return can safely be interpreted as adding a new key.
key - the key which locates the valuevalue - the value to put into the Dictionary
- the previous value of the key, or null if there was none
remove
public abstract V remove(Object key)
Removes from the Dictionary the value located by the given key. A null
return safely means that the key was not mapped in the Dictionary.
key - the key used to locate the value to be removed
- the value associated with the removed key
size
public abstract int size()
Returns the number of values currently in this Dictionary.
- the number of keys in the Dictionary
Dictionary.java -- an abstract (and essentially worthless)
class which is Hashtable's superclass
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