role.java

这是一个基于角色的访问控制程序

/*
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
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 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
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 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
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 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing
 * Applications, University of Illinois, Urbana-Champaign.
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 */
package gov.nist.security.rbac;

import java.util.*;
/** A default implementation of the IRole interface. */
public class Role extends AbstractRole {
  /** The "name" attribute key of this role. */
  public static final String NAME = "name";
  /** An unmodifiable set of permissions assigned to this role.*/
  public final Set permSet;
  /** An unmodifiable map of role attributes, such as name, desc, password, etc. */
  public final Map attr;
  /** Maximum number of user members of this role. */
  public final int maxMembers;
  /** The current set of users assigned with this role. */
  private Set assignedUsers = Collections.synchronizedSet(new HashSet());
  /** Constructs with the given permission. */
  public Role(IPermission perm) {
    this(new IPermission[]{perm}, null, 0);
  }
  /** Constructs with the given set of permissions. */
  public Role(IPermission[] perm) {
    this(perm, null, 0);
  }
  /** Constructs with the given sets of permissions and junior roles. */
  public Role(IPermission[] perm, Map attr, int maxMembers) {
    if (maxMembers < 0) {
      throw new IllegalArgumentException("maxMembers must not be less than zero.");
    }
    this.maxMembers = maxMembers;
    Set ps = new HashSet();

    for (int i=0; i < perm.length; i++) {
      ps.add(perm[i]);
    }
    this.permSet = ps;
    this.attr = Collections.unmodifiableMap(attr == null ? new HashMap() : attr);
  }
  /** Returns true iff this role is authorized with the specified permission. */
/*
  public boolean isAuthorized(IPermission perm) {
    if (perm == null
        || perm == IPermission.NO_PERMISSION
        || perm.equals(IPermission.NO_PERMISSION)) {
        return true;
    }
    if (permSet.contains(IPermission.ALL_PERMISSION)) {
      return true;
    }
    IPermissionEntry[] pe = perm.getPermissionEntries();

  outter:
    for (int i=0; i < pe.length; i++) {
      for (Iterator itr=permSet.iterator(); itr.hasNext();) {
        IPermission p = (IPermission)itr.next();
        IPermissionEntry[] pe1 = p.getPermissionEntries();
        for (int j=0; j < pe1.length; j++) {
          if (pe1[j].ge(pe[i])) {
            continue outter;
          }
        }
      }
      return false;
    }
    return true;
//    return permSet.contains(perm);
  }
*/
  /**
   * Returns the current set of permissions that have been assigned to this role.
   * For advanced permission-role review.
   */
  public IPermission[] getPermissions() {
    synchronized(permSet) {
      return (IPermission[])permSet.toArray(IPermission.ZERO_PERMISSION);
    }
  }
  /**
   * Returns the unmodifiable map of attributes of this role.
   */
  public Map getRoleAttributes() {
    return attr;
  }
  /** Convenient method to return the name of this role. */
  public String getName() {
    return (String)attr.get(NAME);
  }
  /** Returns the maximum number of users this role can be assigned to; or zero if there is no limit. */
  public int getMaxMembers () {
    return  maxMembers;
  }
  //////////// Convenient methods. ///////////
/*
  public String getDesc() {
    return (String)attr.get("desc");
  }
  public Object getAttr(String key) {
    return attr.get(key);
  }
  private void p(String s) {
    System.out.println("Role>>"+s);
  }
*/
  /**
   * Informs this role that it has just been added to the given user.
   * @return true if this role can be successfully added to the given user;
   * or false if this role has already been added.
   * @throws RbacSecurityViolation if the maximum number of user that
   * can be assigned to this role is exceeded.
   */
  public boolean roleAdded(IRbacUser user) throws RbacSecurityViolation {
    if (maxMembers > 0 && assignedUsers.size() == maxMembers) {
      throw new RbacSecurityViolation("More than "
        + maxMembers + " users cannot be assigned to role " + this.getName());
    }
    return assignedUsers.add(user);
  }
  /**
   * Informs this role that it has just been removed from the given user.
   * @return true if this role is successfully removed from the user;
   * or false if there is nothing to remove.
   */
  public boolean roleDropped(IRbacUser user) {
    return assignedUsers.remove(user);
  }
  /**
   * Returns the current set of users this role has been assigned to.
   * (A core RBAC feature.)
   */
  public IRbacUser[] getAssignedUsers () {
    synchronized(assignedUsers) {
      return  (IRbacUser[])assignedUsers.toArray(IRbacUser.ZERO_USER);
    }
  }
  /**
   * Grants the given permission to this role.
   * @return true if the grant is successful;
   * or false if the permission has already been granted.
   */
  public boolean grantPermission(IPermission perm) {
    if (perm == null) {
      return false;
    }
    synchronized(permSet) {
      return permSet.add(perm);
    }
  }
  /**
   * Revokes the given permission from this role.
   * @return true if the revokation is successful;
   * or false if there is no such permission to revoke.
   */
  public boolean revokePermission(IPermission perm) {
    synchronized(permSet) {
      return permSet.remove(perm);
    }
  }
}