abstractpermissionentry.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
 *    notice, this list of conditions and the following disclaimer.
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 * 3. The end-user documentation included with the redistribution, if
 *    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
 * 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.*;
/**
 * A permission entry base class that provides generic implemenation with no internal data set.
 */
public abstract class AbstractPermissionEntry implements IPermissionEntry, Serializable {
  /** Returns an empty string. */
  public String getOperation () {
    return  "";
  }
  /** Returns a dummy object. */
  public Object getObject () {
    return  new Object();
  }
  /**
   * Returns true iff this permission entry is greater than or equal to
   * the given permission entry in terms of access privileges.
   */
  public boolean ge(IPermissionEntry pe) {
    if (pe == null) {
      return true;
    }
    if (pe == this) {
      return true;
    }
    String op = getOperation();
    Object obj = getObject();
    String to_op = pe.getOperation();
    Object to_obj = pe.getObject();

    return (op.equals(ALL_OPERATION) || op.equals(to_op))
        && (obj.equals(ALL_OBJECT) || obj.equals(to_obj));
  }
  /** Two permission entires are equal if they have the same operation and target object. */
  public boolean equals(Object o) {
    if (o == null || !(o instanceof IPermissionEntry)) {
      return false;
    }
    if (o == this) {
      return true;
    }
    IPermissionEntry p = (IPermissionEntry)o;
    return getOperation().equals(p.getOperation()) && getObject().equals(p.getObject());
  }
  public int hashCode() {
    return getOperation().hashCode() ^ getObject().hashCode();
  }
}