package edu.stanford.rt.credential;


/**
 * @author Ninghui Li, Sandra Qiu<br>
 * 
 * Implementation of <code>LinkedRole</code> element.
 */
public class LinkedRole implements PrincipalExpression
{
	private RoleTerm roleTerm1; // required element.
	private RoleTerm roleTerm2; // required element.

    /**
     * Constructor for LinkedRole.
     */
	public LinkedRole(RoleTerm term1, RoleTerm term2)
	{
		roleTerm1 = term1;
		roleTerm2 = term2;
	}

    /**
     * Accessor method for the role terms. 
     */
    public RoleTerm getRoleTermAt(int index) {
        switch(index) {
        case 0: 
            return roleTerm1;
        case 1: 
            return roleTerm2;
        default: 
            return null;
        }
    } 

    /**
	 * @see edu.stanford.rt.credential.PrincipalExpression#toString(String)
	 */
	public String toString(String indent)
	{
		String thisIndent = indent + "  ";

		StringBuffer sb = new StringBuffer();
		sb.append(thisIndent).append("Linked Role: \n");
		sb
			.append(thisIndent + "  ")
			.append(roleTerm1.toString(thisIndent + "  "))
			.append("\n");
		sb
			.append(thisIndent + "  ")
			.append(roleTerm2.toString(thisIndent + "  "))
			.append("\n");
		return sb.toString();
	}

}