package cz.cuni.amis.utils;
   
   /**
    * N-argument key - used to store multiple keys within one object to provide n-argument key for maps.
    * <p><p>
    * The keys are not commutative! If you need to have commutativity for key's parameters use {@link NKeyCommutative}.
    *
    * @author jgemrot
    */
  public class NKey {
  
  	private Object[] keys;
  	private int hashCode;
  
  	/**
  	 * Should be used by descendants together with init()
  	 */
  	protected NKey() {
  
  	}
  
  	public NKey(Object... keys) {
  		init(keys);
  	}
  
  	protected void init(Object[] keys) {
  		this.keys = keys;
  		HashCode hc = new HashCode();
  		for (Object key : keys) {
  			hc.add(key);
  		}
  		this.hashCode = hc.getHash();
  	}
  
  	@Override
  	public int hashCode() {
  		return this.hashCode;
  	}
  
  	@Override
  	public boolean equals(Object obj) {
  		if (obj == null) return false;
  		if (obj.hashCode() != hashCode()) return false;
  		if (!(obj instanceof NKey)) return false;
  		NKey key = (NKey)obj;
  		if (getCount() != key.getCount()) return false;
  		for (int i = 0; i < getCount(); ++i) {
  			if (!SafeEquals.equals(keys[i], key.getKey(i))) return false;
  		}
  		return true;
  	}
  
  	public int getCount() {
  		return keys.length;
  	}
  
  	public Object getKey(int index) {
  		return keys[index];
  	}
  
  	@Override
  	public String toString() {
  		StringBuffer sb = new StringBuffer();
  		sb.append("NKey[");
  		if (keys.length > 0) {
  			sb.append(keys[0]);
  			for (int i = 1; i < keys.length; ++i) {
  				sb.append(", ");
  				sb.append(keys[i]);
  			}
  		}
  		sb.append("]");
  		return sb.toString();
  	}
  
  }