package gw.util.concurrent;

import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 */
public class ConcurrentHashSet<K> implements Set<K> {
  private final ConcurrentMap<K, Boolean> _map;

  public ConcurrentHashSet() {
    _map = new ConcurrentHashMap<K, Boolean>();
  }

  public ConcurrentHashSet( int initialCapacity ) {
    _map = new ConcurrentHashMap<K, Boolean>( initialCapacity );
  }

  public ConcurrentHashSet( Set<K> set ) {
    _map = new ConcurrentHashMap<K, Boolean>( set.size() );
    for( K value: set ) {
      _map.put( value, Boolean.TRUE );
    }
  }

  public int size() {
    return _map.size();
  }

  public boolean isEmpty() {
    return _map.isEmpty();
  }

  public boolean contains( Object o ) {
    return _map.containsKey( o );
  }

  public Iterator<K> iterator() {
    return _map.keySet().iterator();
  }

  public Object[] toArray() {
    return _map.keySet().toArray();
  }

  public <T> T[] toArray( T[] a ) {
    return _map.keySet().toArray( a );
  }

  public boolean add( K o ) {
    return _map.putIfAbsent( o, Boolean.TRUE ) == null;
  }

  public boolean remove( Object o ) {
    return _map.keySet().remove( o );
  }

  public boolean containsAll( Collection<?> c ) {
    return _map.keySet().containsAll( c );
  }

  public boolean addAll( Collection<? extends K> c ) {
    boolean ret = false;
    for( K value: c ) {
      ret |= add( value );
    }

    return ret;
  }

  public boolean retainAll( Collection<?> c ) {
    return _map.keySet().retainAll( c );
  }

  public boolean removeAll( Collection<?> c ) {
    return _map.keySet().removeAll( c );
  }

  public void clear() {
    _map.clear();
  }

  @Override
  public String toString() {
    return _map.keySet().toString();
  }
}