/*
 * Solution.java
 */
package janet.applications.branchandbound;
import  janet.applications.branchandbound.Q;
import  janet.services.*;
import java.util.*;

/** The interface of an object that represents a solution to a branch & bound
 * search.
 * @author Peter Cappello
 * @version 1.0
 */
public interface Solution extends java.io.Serializable
{            
    /** returns an LinkedList of the Solution objects that are the children of
     * this Solution.
     * @param problem An object that represents the input of this branch & bound 
	 * search.
     * For example, in a traveling salesman problem, it could be a distance matrix.
     * @param upperBound The best known cost of a Solution for this problem.
     * @return an Q of [partial] Solution objects that represent the children
     * of the node in the search tree represented by this [partial] Solution.
     */    
    public Q getChildren( Object problem, int upperBound );
    
    /** returns the lower bound on the cost of any complete Solution that is an
     * extension of this partial Solution.
     * @return the lower bound on the cost of any complete Solution that is an
     * extension of this partial Solution.
     */    
    public int getLowerBound();
        
    /** returns true if and only if this solution should be explored directly by
     * a Host (as opposed to being further decomposed).
     * @return true if and only if this solution should be explored directly by
     * a Host (as opposed to being further decomposed).
     * @param myTask a reference to the task encapsulating this partial solution.
     * This may be used when the question of whether or not the solution
     * is atomic depends on task properties, such as whether this task
     * has been assigned more than once (suggesting that it may be big).
     */    
    public boolean isAtomic( Task myTask );
    
    /** returns true if and only if the partial Solution is, in fact, complete.
     * @return true if and only if the partial Solution is, in fact, complete.
     */    
    public boolean isComplete();

    /** returns a String representation of this partial solution.
     * @return a String representation of this partial solution.
     */    
    public String toString();
}