package cz.cuni.amis.utils.flag.connective;
   
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.HashSet;
   import java.util.List;
   import java.util.Set;
   
   import cz.cuni.amis.utils.HashCode;
  import cz.cuni.amis.utils.flag.Flag;
  
  /**
   * Used to create logical expression out of different flags. (Warning: spagetthi code ahead!)
   * @author Jimmy
   */
  public abstract class Connective extends Flag<Boolean> {
  	
  	protected List<ConnectiveListener> listeners = new ArrayList<ConnectiveListener>();
  	
  	protected int[] truthValue = new int[]{0};
  	
  	protected Set<Flag<Boolean>> flags = new HashSet<Flag<Boolean>>();
  	
  	private int hashCode = 0;
  	
  	public Connective(Flag<Boolean> flag1, Flag<Boolean> flag2) {
  		this(new Flag[]{flag1, flag2});
  	}
  
  	public Connective(Flag<Boolean>[] flags) {
  		if (flags.length > Integer.SIZE) throw new IllegalArgumentException("Can't have connective with more then " + Integer.SIZE + " arguments (int bit count).");
  		synchronized(truthValue) {
  			int i = 0;
  			Arrays.sort(flags);
  			HashCode hc = new HashCode();
  			for (Flag<Boolean> flag : flags) {
  				this.flags.add(flag);
  				hc.add(flag);
  				ConnectiveListener listener = new ConnectiveListener(this, flag, i);
  				listeners.add(listener);
  				++i;			
  			}
  			hashCode = hc.getHash();
  		}
  	}
  	
  	public int hashCode() {
  		return hashCode;
  	}
  	
  	protected abstract void truthValueChanged();
  
  }