import java.lang.Integer;
import java.lang.Boolean;

/**
 * <p>
 * Implementation of ILogicVarBundle for storing no variables.
 * Preferable to just passing a null pointer for correctness-checking
 * reasons.
 * </p>
 * @author     Michael Schuresko
 * @version    %I%, %G%
 * @since      1.0
 */
class NullLogicVarBundle implements ILogicVarBundle
{


    public NullLogicVarBundle() { m_nId = -1;}
    
    public NullLogicVarBundle(int nId) { m_nId = nId; }

    public NullLogicVarBundle(NullLogicVarBundle src) {
	m_nId = src.m_nId;
    }

    /**
     * makes a copy and returns it
     */
    public ILogicVarBundle makeCopy() 
    { 
	return new NullLogicVarBundle(this); 
    }


	/**
	 * Does nothing, for the time being.
	 */
	public void init() { }
	


    /**
     * gets an Integer (wrapping an int) referred to by an object.
     * returns null if refObject is of invalid type
     * or indexes an invalid logic var.
     *
     * <i>Note: The original specification only allowed boolean
     * variables in this place.  Obviously some applications may
     * want to use collections of boolean variables to represent
     * integers over a finite fixed range, or rationals with
     * finite fixed precision over a finite fixed range.
     * This function is merely provided as a shortcut towards this end.</i>
     */
    public Integer getIntVar(Object refObject) { return null; }

    
    /**
     * Removes any values indexed by refObject
     * @param refObject remove values associated with this.
     */
    public void removeVar(Object refObject) {
    	return;
    }
    
    /**
     * inserts an integer value (see getIntvar).  Returns false
     * if this insert was not permitted
     * @see getIntVar
     */
    public boolean insertIntVar(Object refObject, int nValue) { return false; }

    /**
     * gets a Boolean (wrapping a boolean) referred to by an object.
     * returns null if refObject is of invalid type 
     * or indexes an invalid logic var.
     */
    public Boolean getBoolVar(Object refObject) { return null; }

    /**
     * inserts an boolean value (see getBoolVar).  Returns false
     * if this insert was not permitted
     * @see getBoolVar
     */
    public boolean insertBoolVar(Object refObject, boolean bValue) 
    { return false; }

    int m_nId;

    /**
     * Gets unique Id of this agent
     */
    public int getId() { return m_nId; }

    /**
     * Sets unique Id of this agent
     */
    public void setId(int nId) { m_nId = nId; }

}