package edu.stanford.rt.credential;
/**
 * @author Ninghui Li, Sandra Qiu<br>
 * 
 * Implementation of <code>Role</code> object in RTML.
 * A role consists of 2 parts: a principal and a role term. 
 */
public class Role implements PrincipalExpression
{
	private Principal principal; // required element.
	private RoleTerm roleTerm; // required element.
	/**
	 * Constructor for Role.
	 */
	public Role(Principal principal, RoleTerm roleTerm)
	{
		this.principal = principal;
		this.roleTerm = roleTerm;
	}
	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode()
	{
		return getPrincipal().hashCode() * 2 + getName().hashCode();
	}
	/**
	 * Two roles are equal if both their principals are equal and 
	 * the role names are equal.
	 * 
	 */
	public boolean equals(Object o)
	{
		return (o instanceof Role)
			&& getPrincipal().equals(((Role) o).getPrincipal())
			&& getName().equals(((Role) o).getName());
	}
	/**
	 * Returns the principal.
	 * @return Principal
	 */
	public Principal getPrincipal()
	{
		return principal;
	}
	/**
	 * Returns the roleTerm.
	 * @return RoleTerm
	 */
	public RoleTerm getRoleTerm()
	{
		return roleTerm;
	}
	/**
	 * Method getRoleDeclaration.
	 * @return RoleDeclaration
	 * 		The corresponding role declaration.
	 */
	public RoleDeclaration getRoleDeclaration()
	{
		return roleTerm.getRoleDeclaration();
	}
	/**
	 * Method getName.
	 * @return String
	 * 		The role name.
	 */
	public String getName()
	{
		return roleTerm.getRoleDeclaration().getName();
	}
	/* (non-Javadoc)
	 * @see edu.stanford.rt.credential.PrincipalExpression#toString(String)
	 */
	public String toString(String indent)
	{
		String thisIndent = indent + "  ";

		StringBuffer sb = new StringBuffer();
		sb.append(thisIndent).append("Role: \n");
		if (principal != null)
			sb.append(principal.toString(thisIndent + "  ")).append(
				"\n");
		sb.append(roleTerm.toString(thisIndent + "  ")).append("\n");
		return sb.toString();
	}
}