package OT;

import java.util.*;

/**
 * Abstract constraint.
 * @version 1999-03-31
 * @author Andrea Heiberg, University of Arizona
*/
public abstract class Constraint implements Cloneable {
	protected boolean global;
	protected Edge edge;
	protected FeatureType featureType1;
	protected FeatureType featureType2;
	
	public Constraint(FeatureType featureType1, FeatureType featureType2, Edge edge, boolean global) {
		this.featureType1 = featureType1;
		this.featureType2 = featureType2;
		this.edge = edge;
		this.global = global;
	} //end constructor
	
	/** Culls Gen operations as appropriate for this constraint. **/ 
	abstract Gen cullGen(Gen gen);
	
	/** Calculates the number of times that candidate violates this constraint. */
	abstract Integer evaluate(Representation candidate, Representation input);

	/** Returns the optimal candidates on this constraint from currentCandidates. **/
	public Vector getOptimalCandidates(Vector currentCandidates, RepresentationSet allCandidates) {
		Vector newOptimalCandidates = new Vector();
		int violations;
		int candidateViolations;

		Vector optimalCandidates = (Vector)currentCandidates.clone();

		//if there is only one candidate, it's the optimal candidate
		if (optimalCandidates.size()>1) {
				violations = 1000000; //set to a really big number
				for (Enumeration e = optimalCandidates.elements(); e.hasMoreElements();) {
					String key = (String)e.nextElement();
					Representation candidate = (Representation)allCandidates.get(key);
					candidateViolations = candidate.getViolations(this).intValue();
					if (candidateViolations==-1) {
						candidate.debug.write(this + ", c" + key + ": " + candidateViolations);
					} else if (candidateViolations==violations) {
						//tie; add to set
						newOptimalCandidates.addElement(key);
					} else if (candidateViolations < violations) {
						//this one is better than the ones we're already collected
						newOptimalCandidates.removeAllElements();
						newOptimalCandidates.addElement(key);
						violations = candidateViolations;
					} //end if
				} //end for
				optimalCandidates = (Vector)newOptimalCandidates.clone();
		} //end if

		optimalCandidates.trimToSize();
		return optimalCandidates;
	} //end getOptimalCandidates
	
}