source: fedd/abac-src/rtml/src/edu/stanford/rt/credential/RoleIntersection.java @ af51a97

package edu.stanford.rt.credential;

import java.util.*;

/**
 * @author Ninghui Li, Sandra Qiu<br>
 * 
 * Implementation of <code>IntersectionContainment</code> element.
 * 
 */
public class RoleIntersection implements PrincipalExpression
{
    /**
     * list of members in this intersection.
     */
        private ArrayList parts; // required element.

    /**
     * Constuctor for an empty RoleIntersection.
     */
        public RoleIntersection()
        {
                parts = new ArrayList();
        }

    /**
     * Constructor for RoleIntersection
     */
        public RoleIntersection(List p)
        {
                if (p == null || p.size() == 0)
                        throw new IllegalArgumentException("RoleIntersection: empty parts.");
                // copy over 
                parts = new ArrayList();
                Iterator it = p.iterator();
                while (it.hasNext())
                {
                        Object pr = it.next();
                        if (!(pr instanceof RoleTerm) && !(pr instanceof Role))
                                throw new IllegalArgumentException("RoleIntersection: wrong element type");
                        parts.add(pr);
                }
        }

        /**
         * Method getParts.
     * returns an unmodifiable view of the members.
         * @return List
         */
        public List getParts()
        {
                return Collections.unmodifiableList(parts);
        }

        /**
         * Method and.
     *  AND operation.
         * @param part
         * @throws CredException
         */
        public void and(Object part) throws CredException
        {
                if (!(part instanceof RoleTerm) && !(part instanceof Role))
                        throw new CredException("Illegal part type");

                // add this new part to the set.
                if (!parts.contains(part))
                        parts.add(part);

        }

        /* (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 Intersection: \n");
                for (int i = 0; i < parts.size(); i++)
                {
                        if ((parts.get(i)) instanceof Role)
                        {
                                sb.append(
                                        ((Role) parts.get(i)).toString(
                                                thisIndent + "  "));
                        }
                        else if ((parts.get(i)) instanceof RoleTerm)
                        {
                                sb.append(
                                        ((RoleTerm) parts.get(i)).toString(
                                                thisIndent + "  "));
                        }
                        sb.append("\n");
                }
                return sb.toString();
        }

}