clock.java

一个完整的XACML工程,学习XACML技术的好例子!

/*
* Copyright (c) 2000-2005, University of Salford
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this 
* list of conditions and the following disclaimer.
* 
* Redistributions in binary form must reproduce the above copyright notice, 
* this list of conditions and the following disclaimer in the documentation 
* and/or other materials provided with the distribution. 
*
* Neither the name of the University of Salford nor the names of its 
* contributors may be used to endorse or promote products derived from this 
* software without specific prior written permission. 
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
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*/

package issrg.pba.rbac;

import java.util.Calendar;

/**
 * This is the abstract class that provides the RelativeValidityPeriod and 
 * decision with current time.
 * The simplest implementation just gets the system time. You may wish to 
 * provide a secure
 * clock, obtaining the time from a time-stamping authority.
 *
 * <p>The latch method is used to get current time that will be used in 
 * subsequent calls
 * to getTime method. This use ensures that the time will remain the same 
 * during long calculations. This is needed when making decisions to ensure 
 * that "current 
 * time" is the same
 * during the whole process.
 *
 * @author A.Otenko
 */

public abstract class Clock extends Time {

  /**
   * This array is created once at construction time to save time each time 
   * getEvaluationTime is called
   */
  private final int [] time = new int[6]; // day of week is not implemented yet, so array size is 6, not 7

  /**
   * This method gets the actual time and keeps it for later reference. 
   * Subsequent
   * calls to getTime will return the same value (needed in operations extended 
   * in time).
   *
   * @return the current time
   */
  public abstract java.util.Date latch();

  /**
   * This method returns the time returned by the last call to latch, so all 
   * calculations
   * will be consistent.
   *
   * @return the time returned by the last call to latch
   */
  public abstract java.util.Date getTime();

  /**
   * This method calls getTime() and converts it into the array of integers, so 
   * it can
   * be compared by the TimeInterpreter.
   *
   * <p>Returns an array of integers representing the year, month, day
   * hour, minute, second. If the value of the array element
   * is -1, then the value is not specified ("don't care" when comparing)
   *
   * @return array of integers, each element standing for y,m,d,h,m,s
   */
  public int [] getEvaluationTime(){
    Calendar c=new java.util.GregorianCalendar(); // initialised with current day and time
    c.setTime(getTime());

    time[0]=c.get(Calendar.YEAR);
    time[1]=c.get(Calendar.MONTH);
    time[2]=c.get(Calendar.DAY_OF_MONTH);
    //time[3]=c.get(Calendar.DAY_OF_WEEK); // day of week not implemented yet

    time[/*4*/3]=c.get(Calendar.HOUR_OF_DAY);
    time[/*5*/4]=c.get(Calendar.MINUTE);
    time[/*6*/5]=c.get(Calendar.SECOND);

    return time;
  }

}