Variable.java

package crossnum;

import java.util.Comparator;

/**
 * Represents an integer variable value, with some special functionality to support
 * the algorithm in CrossNum.
 *
 * @author dub_nerd
 *
 */
public class Variable {

    /**
     * The value of this variable.
     */
    private int value;

    /**
     * An ordinal value which can function as a label for the variable.
     */
    private int ordinal = -1;

    /**
     * Variable values may be locked against modification. If the
     * lockHolder is non-null the variable is locked.
     */
    private Object lockHolder;

    /**
     * A convenience Comparator for sorting by ordinal value
     */
    static public Comparator<Variable> sortByOrdinal = new Comparator<Variable>() {

        @Override
        public int compare(Variable o1, Variable o2) {
            return o1.getOrdinal() > o2.getOrdinal()? 1 : o1.getOrdinal() == o2.getOrdinal()? 0 : -1;
        }
    };

    /**
     * Construct a new Variable.
     *
     * @param val
     *            the variable value
     */
    public Variable(int val) {
        value = val;
    }

    // Various accessor methods

    public int getValue() {
        return value;
    }


    public void setValue(int value) {
        this.value = value;
    }


    public int getOrdinal() {
        return ordinal;
    }


    public void setOrdinal(int ord) {
        this.ordinal = ord;
    }


    public Object getLock() {
        return lockHolder;
    }


    public boolean isLocked() {
        return lockHolder != null;
    }


    public void lock(Object holder) {
        lockHolder = holder;
    }

}