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Préférences
Moteurs de recherche
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JavaTM 2 Platform Std. Ed. v1.6.0
java.util
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Constructor Summary | |
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Dictionary()
Sole constructor. |
Method Summary | |
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abstract Enumeration<V> |
elements()
Returns an enumeration of the values in this dictionary. |
abstract V |
get(Object key)
Returns the value to which the key is mapped in this dictionary. |
abstract boolean |
isEmpty()
Tests if this dictionary maps no keys to value. |
abstract Enumeration<K> |
keys()
Returns an enumeration of the keys in this dictionary. |
abstract V |
put(K key,
V value)
Maps the specified key to the specified
value in this dictionary. |
abstract V |
remove(Object key)
Removes the key (and its corresponding
value ) from this dictionary. |
abstract int |
size()
Returns the number of entries (distinct keys) in this dictionary. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public Dictionary()
Method Detail |
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public abstract int size()
public abstract boolean isEmpty()
true
if this dictionary maps no keys to values;
false
otherwise.public abstract Enumeration<K> keys()
elements()
,
Enumeration
public abstract Enumeration<V> elements()
keys()
,
Enumeration
public abstract V get(Object key)
key
- a key in this dictionary.
null
if the key is not mapped to any value in
this dictionary.
NullPointerException
- if the key is null.put(java.lang.Object, java.lang.Object)
public abstract V put(K key, V value)
key
to the specified
value
in this dictionary. Neither the key nor the
value can be null
.
If this dictionary already contains an entry for the specified key, the value already in this dictionary for that key is returned, after modifying the entry to contain the new element.
If this dictionary does not already have an entry for the specified key, an entry is created for the specified key and value, and null is returned.
The value
can be retrieved by calling the
get
method with a key
that is equal to
the original key
.
key
- the hashtable key.value
- the value.
key
was mapped
in this dictionary, or null
if the key did not
have a previous mapping.
NullPointerException
- if the key
or
value
is null
.Object.equals(java.lang.Object)
,
get(java.lang.Object)
public abstract V remove(Object key)
key
(and its corresponding
value
) from this dictionary. This method does nothing
if the key
is not in this dictionary.
key
- the key that needs to be removed.
key
had been mapped in this
dictionary, or null
if the key did not have a
mapping.
NullPointerException
- if key is null.