itemset.java

粗糙集遗传算法例程

import java.io.*;
import java.lang.*;
import java.util.*;

public class ItemSet extends HashSet
{
  ItemSet()
  {   
    super();
  }

  ItemSet( Collection c )
  {
    super(c);
  }
/* Removed for extends TreeSet
  public boolean equals( Object o )
  {
    if( o instanceof ItemSet )
      return( (this.difference((ItemSet)o)).size() == 0 );
    else
      return( super.equals(o) );
  }
*/
/*
  public Iterator begin()
  {
    return this.iterator();
  }
*/
  public ItemSet union(Collection c)
  {
    ItemSet set = new ItemSet(this);
//    set.addAll( ((ItemSet)c).difference(this) );
      set.addAll( c );
  return set;
  }  

  public void unionWith(Collection c)
  {
    this.addAll(c);
  }

  public ItemSet difference(Collection s)
  {
    ItemSet set = new ItemSet(this);
    set.removeAll(s);
  return set;
  }

  public ItemSet intersection(Collection s)
  {
    ItemSet set = new ItemSet(this);
    set.retainAll(s);
  return set;
  }

  public boolean subsetOf(Collection c)
  {
    return( c.containsAll(this) );
  }    

  public void copy(Collection c)
  {
    this.union(c);
  }
/* Removed fore treeset
  public boolean add(Object c)
  {
    if( this.contains(c) )
      return false;
    else
      return( super.add(c) );
  }
*/
}