Java Reference
In-Depth Information
public
public void
void remove () {
throw
throw new
new UnsupportedOperationException ( "remove" );
}
};
}
WARNING
This is just to show how the implementation of a linked list might work. Do not use the
simple LinkList class shown here; use the real one, java.util.LinkedList , shown in
action in the first example.
Mapping with Hashtable and HashMap
Problem
You need a one-way mapping from one data item to another.
Solution
Use a HashMap or the older Hashtable .
Discussion
HashMap and the older Hashtable provide a one-way mapping from one set of object refer-
ences to another. They are completely general purpose. I've used them to map Swing push
buttons (see Action Handling: Making Buttons Work ) to the URL to jump to when the button
is pushed, to map names to addresses, and to implement a simple in-memory cache in a web
server. You can map from anything to anything. In the following example, we map from
company names to addresses; the addresses here are String objects, but in real life they'd
probably be Address objects:
public
public class
class HashMapDemo
HashMapDemo {
public
public static
static void
void main ( String [] argv ) {
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