Re: How to code something in Java

ram@zedat.fu-berlin.de (Stefan Ram) writes:


  One might remove the need for the above
  call to ?p? to simplify the interface:

class P<E>
{ final E[] value;
  public P( final E ... value ){ this.value = value; }
  public int hashCode(){ return java.util.Arrays.hashCode( value ); }
  public boolean equals( final java.lang.Object value )
  { return value instanceof P ? java.util.Arrays.equals
    ( this.value,(( P )value ).value ): false; }}

interface MultiMap<K,V>
{ public void set( final V value, final K ... keys );
  public V get( final K ... keys ); }

class MultiHashMap<K,V> extends java.util.HashMap<P<K>,V>
implements MultiMap<K,V>
{ public void set( final V value, final K ... keys )
  { put( new P<K>( keys ), value ); }
  public V get( final K ... keys ){ return get( new P<K>( keys )); }}

public class Main
{ static final MultiMap<java.lang.Character,java.lang.Integer> map
  = new MultiHashMap<java.lang.Character,java.lang.Integer>();

  public static void main( final java.lang.String[] args )
  {
    map.set( 3, 'a', 'b' );
    map.set( 5, 'a', 'y' );

    java.lang.System.out.println( map.get( 'a', 'b' ));
    java.lang.System.out.println( map.get( 'a', 'y' )); }}

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