abstractrole.java

这是一个基于角色的访问控制程序

/*
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
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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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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <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.io.*;
import  java.util.*;

/**
 * A role base class that provides generic implemenation with no internal data set.
 */
public class AbstractRole implements IRole, Serializable {
  /** 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;
    }
    return new Permission(getPermissions()).ge(perm);
  }
  /** Returns true iff this role is authorized with the specified permissions. */
  public boolean isAuthorized (IPermission[] perm) {
    if (perm == null) {
        return true;
    }
    return new Permission(getPermissions()).ge(new Permission(perm));
  }
  /** Always returns zero. */
  public int getMaxMembers () {
    return  0;
  }
  /** Always returns a null set of user. */
  public IRbacUser[] getAssignedUsers () {
    return  IRbacUser.ZERO_USER;
  }
  /** Always returns a null set of permission. */
  public IPermission[] getPermissions () {
    return  IPermission.ZERO_PERMISSION;
  }
  /** Always returns a non-modifiable empty set of attributes. */
  public Map getRoleAttributes () {
    return  Collections.unmodifiableMap(new HashMap());
  }
  /** Two roles are equal if they have the same set of attributes and permissions. */
  public boolean equals (Object o) {
    if (o == null || !(o instanceof IRole)) {
      return  false;
    }
    if (o == this) {
      return true;
    }
    IRole r = (IRole)o;
    Map attr = getRoleAttributes();
    IPermission[] p = getPermissions();
    Map to_attr = r.getRoleAttributes();
    IPermission[] to_p = r.getPermissions();
    if (!attr.equals(to_attr))
      return  false;
    if (p.length != to_p.length)
      return  false;
  outter:
    for (int i = 0; i < p.length; i++) {
      IPermission pi = p[i];

      for (int j = 0; j < to_p.length; j++) {
        IPermission pj = to_p[j];

        if (pi.equals(pj)) {
          continue outter;
        }
      }
      return false;
    }
    return  true;
  }

  public int hashCode () {
    int hash = getRoleAttributes().hashCode();
    IPermission[] p = getPermissions();
    if (p != null) {
      for (int i=0; i < p.length; i++) {
        hash ^= p[i].hashCode();
      }
    }
    return hash;
  }
  /**
   * Returns true iff the access privilege this role is
   * greater than or equal to that of the given role.
   */
  public boolean ge(IRole r) {
    if (r == null || r == this) {
      return true;
    }
    IPermission[] p = getPermissions();
    IPermission[] to_p = r.getPermissions();
  outter:
    for (int i = 0; i < to_p.length; i++) {
      IPermission pi = to_p[i];

      for (int j = 0; j < p.length; j++) {
        IPermission pj = p[j];

        if (pj.ge(pi)) {
          continue outter;
        }
      }
      return false;
    }
    return  true;
  }
  public String toString() {
    StringBuffer sb = new StringBuffer();
    Map map = getRoleAttributes();

    for (Iterator itr=map.entrySet().iterator(); itr.hasNext();) {
      Map.Entry entry = (Map.Entry)itr.next();
      sb.append("\n");
      sb.append(entry.getKey().toString());
      sb.append("=");
      sb.append(entry.getValue().toString());
    }
    IPermission[] p = getPermissions();
    for (int i=0; i < p.length; i++) {
      sb.append("\n");
      sb.append(p[i].toString());
    }
    return sb.toString();
  }
  /** Always returns false. */
  public boolean roleAdded(IRbacUser user) throws RbacSecurityViolation {
    return false;
  }
  /** Always returns false. */
  public boolean roleDropped(IRbacUser user) {
    return false;
  }
  /** Always returns false. */
  public boolean grantPermission(IPermission perm) {
    return false;
  }
  /** Always returns false. */
  public boolean revokePermission(IPermission perm) {
    return false;
  }
}