| java.lang.Object
 java.util.Dictionary
| Dictionary | | abstract public class Dictionary (Code) | | The Dictionary class is the abstract parent of any
class, such as Hashtable, which maps keys to values.
Every key and every value is an object. In any one Dictionary
object, every key is associated with at most one value. Given a
Dictionary and a key, the associated element can be looked up.
Any non-null object can be used as a key and as a value.
As a rule, the equals method should be used by
implementations of this class to decide if two keys are the same.
NOTE: This class is obsolete. New implementations should
implement the Map interface, rather than extending this class.
author:
unascribed
version:
1.15, 02/02/00
See Also: java.util.Map
See Also: java.lang.Object.equals(java.lang.Object)
See Also: java.lang.Object.hashCode
See Also: java.util.Hashtable
since:
JDK1.0 |
| Constructor Summary | |
| public | Dictionary()
Sole constructor. |
| Method Summary | |
| abstract public Enumeration | elements()
Returns an enumeration of the values in this dictionary. | | abstract public Object | get(Object key)
Returns the value to which the key is mapped in this dictionary. | | abstract public boolean | isEmpty()
Tests if this dictionary maps no keys to value. | | abstract public Enumeration | keys()
Returns an enumeration of the keys in this dictionary. | | abstract public Object | put(Object key, Object value)
Maps the specified key to the specified
value in this dictionary. | | abstract public Object | remove(Object key)
Removes the key (and its corresponding
value) from this dictionary. | | abstract public int | size()
Returns the number of entries (dinstint keys) in this dictionary. |
| Dictionary | | public Dictionary()(Code) | | Sole constructor. (For invocation by subclass constructors, typically
implicit.)
|
| elements | | abstract public Enumeration elements()(Code) | | Returns an enumeration of the values in this dictionary. The general
contract for the elements method is that an
Enumeration is returned that will generate all the elements
contained in entries in this dictionary.
an enumeration of the values in this dictionary.
See Also: java.util.Dictionary.keys
See Also: java.util.Enumeration |
| get | | abstract public Object get(Object key)(Code) | | Returns the value to which the key is mapped in this dictionary.
The general contract for the isEmpty method is that if this
dictionary contains an entry for the specified key, the associated
value is returned; otherwise, null is returned.
the value to which the key is mapped in this dictionary;
Parameters:
key - a key in this dictionary.null if the key is not mapped to any value inthis dictionary.
exception:
NullPointerException - if the key is null.
See Also: java.util.Dictionary.put(java.lang.Objectjava.lang.Object) |
| isEmpty | | abstract public boolean isEmpty()(Code) | | Tests if this dictionary maps no keys to value. The general contract
for the isEmpty method is that the result is true if and only
if this dictionary contains no entries.
true if this dictionary maps no keys to values;false otherwise. |
| keys | | abstract public Enumeration keys()(Code) | | Returns an enumeration of the keys in this dictionary. The general
contract for the keys method is that an Enumeration object
is returned that will generate all the keys for which this dictionary
contains entries.
an enumeration of the keys in this dictionary.
See Also: java.util.Dictionary.elements
See Also: java.util.Enumeration |
| put | | abstract public Object put(Object key, Object value)(Code) | | Maps the specified 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.
Parameters:
key - the hashtable key.
Parameters:
value - the value. the previous value to which the key was mappedin this dictionary, or null if the key did nothave a previous mapping.
exception:
NullPointerException - if the key orvalue is null.
See Also: java.lang.Object.equals(java.lang.Object)
See Also: java.util.Dictionary.get(java.lang.Object) |
| remove | | abstract public Object remove(Object key)(Code) | | Removes the key (and its corresponding
value) from this dictionary. This method does nothing
if the key is not in this dictionary.
Parameters:
key - the key that needs to be removed. the value to which the key had been mapped in thisdictionary, or null if the key did not have amapping.
exception:
NullPointerException - if key is null. |
| size | | abstract public int size()(Code) | | Returns the number of entries (dinstint keys) in this dictionary.
the number of keys in this dictionary. |
|
|